Roger.

[image: IMG_20230220_230829904.jpg] That is what it looks like to me. Excuse the rubbish photo, I only have a phone with me. This is my attempt to model what I see. [image: image.png] On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: > I've never seen a higbee end either. But I've also never seen a machine > screw with a tapered thread like you are describing. You have screws where > there is a full thread that gradually disappears by decreasing radius into > the shaft, and it's not because of a small bevel on the end? Mine all have > the shaft beveled. > > On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: > >> Yes. The only things I have bevelled are leadscrews and studding cut to >> length that I bevel myself on a grinder. I have never seen a higbee end. >> >> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> wrote: >> >>> You have machine screws where the threads taper at the ends? Like I >>> said...mine don't do that. The end is just beveled. >>> >>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> wrote: >>> >>>> I do it over half a turn because that is what my machine screws look >>>> like they do and that is what I am trying to realistically draw. >>>> >>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>>> So lineiar decrease in diameter of the thread? Something like >>>>> this? I have two views for clarity: >>>>> >>>>> [image: image.png] >>>>> >>>>> >>>>> [image: image.png] >>>>> Why would you want to extend the taper for a full half-turn. My >>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>> wonder if really very short is best. Doesn't the section where the >>>>> diameter of the thread is reduced enable you to hop over it to >>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>> success here: you can't hop into the next thread because you have a full >>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>> know what they're doing? Their standard doesn't specify this, but in >>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>> size of the threads, and nothing to do with angle, though. >>>>> >>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> Tapered by making the thread diameter decrease until it is below the >>>>>> minor diameter and disappears. I do it linearly over half a turn but your >>>>>> bottle example was much less. >>>>>> >>>>>> Higbee removes the crests instead because the thread is already >>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>> >>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>> wrote: >>>>>> >>>>>>> So "simply tapered" is not well-defined. Tapered how, and over what >>>>>>> length? In both directions or just one? And why is that clearly >>>>>>> optimal. >>>>>>> >>>>>>> >>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> wrote: >>>>>>> >>>>>>>> Thinking some more about it, I think higbee only makes sense when >>>>>>>> you have a thread already made and you want to clean up the end. The >>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>> >>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff <R.E.Wolff@bitwizard.nl> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano wrote: >>>>>>>>> > I looked for info on how screws are made and it sounds like the >>>>>>>>> > normal way is indeed to press them between a pair of flat dies. >>>>>>>>> > This process could not make a higbee end. >>>>>>>>> >>>>>>>>> I checked out your link, because I didn't think the shape of a >>>>>>>>> screw >>>>>>>>> could be pressed between two dies. >>>>>>>>> >>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In hindsight >>>>>>>>> The hint was there with the /flat/ dies, but for sure they cannot >>>>>>>>> be >>>>>>>>> FLAT because that'd make them "cylindrical" instead of a screw. >>>>>>>>> >>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of a big >>>>>>>>> wheel (*)) so that you can rotate them. rotate them in opposite >>>>>>>>> directions so that the screws remain stationary. Then turn one >>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>> between >>>>>>>>> the two big dies after enough of an impression has been made. Feed >>>>>>>>> a >>>>>>>>> new pre-screw in due time. I'd think one machine can then thread >>>>>>>>> 36000 >>>>>>>>> screws per hour easily.) >>>>>>>>> >>>>>>>>> Roger. >>>>>>>>> >>>>>>>>> (*) You can calculate the size of the required wheel by knowing >>>>>>>>> howmany rotations of the screw you want between the dies (i.e. >>>>>>>>> length >>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>> >>>>>>>>> -- >>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>> +31-15-2049110 ** >>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>> 27239233 ** >>>>>>>>> f equals m times a. When your f is steady, and your m is going down >>>>>>>>> your a is going up. -- Chris Hadfield about flying up the space >>>>>>>>> shuttle. >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

The pic is a alas too rubbish for me to tell what' going on, but it looks like it might be like my screws, which have a beveled end, not the feature you're describing. Note that it's a small bevel, like the size of one thread, so it has the effect of cutting off part of the thread and could produce the illusion of an intentional taper like you're describing. I inspected my screws under 10x magnification to figure out what was going on. On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: > [image: IMG_20230220_230829904.jpg] > That is what it looks like to me. Excuse the rubbish photo, I only have a > phone with me. > > This is my attempt to model what I see. > > [image: image.png] > > > > > > On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: > >> I've never seen a higbee end either. But I've also never seen a machine >> screw with a tapered thread like you are describing. You have screws where >> there is a full thread that gradually disappears by decreasing radius into >> the shaft, and it's not because of a small bevel on the end? Mine all have >> the shaft beveled. >> >> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >> >>> Yes. The only things I have bevelled are leadscrews and studding cut to >>> length that I bevel myself on a grinder. I have never seen a higbee end. >>> >>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>>> You have machine screws where the threads taper at the ends? Like I >>>> said...mine don't do that. The end is just beveled. >>>> >>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> wrote: >>>> >>>>> I do it over half a turn because that is what my machine screws look >>>>> like they do and that is what I am trying to realistically draw. >>>>> >>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> wrote: >>>>> >>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>> this? I have two views for clarity: >>>>>> >>>>>> [image: image.png] >>>>>> >>>>>> >>>>>> [image: image.png] >>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>> wonder if really very short is best. Doesn't the section where the >>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>> success here: you can't hop into the next thread because you have a full >>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>> size of the threads, and nothing to do with angle, though. >>>>>> >>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> wrote: >>>>>> >>>>>>> Tapered by making the thread diameter decrease until it is below the >>>>>>> minor diameter and disappears. I do it linearly over half a turn but your >>>>>>> bottle example was much less. >>>>>>> >>>>>>> Higbee removes the crests instead because the thread is already >>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>> >>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> So "simply tapered" is not well-defined. Tapered how, and over >>>>>>>> what length? In both directions or just one? And why is that clearly >>>>>>>> optimal. >>>>>>>> >>>>>>>> >>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Thinking some more about it, I think higbee only makes sense when >>>>>>>>> you have a thread already made and you want to clean up the end. The >>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>> >>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff <R.E.Wolff@bitwizard.nl> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano wrote: >>>>>>>>>> > I looked for info on how screws are made and it sounds like the >>>>>>>>>> > normal way is indeed to press them between a pair of flat dies. >>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>> >>>>>>>>>> I checked out your link, because I didn't think the shape of a >>>>>>>>>> screw >>>>>>>>>> could be pressed between two dies. >>>>>>>>>> >>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>> hindsight >>>>>>>>>> The hint was there with the /flat/ dies, but for sure they cannot >>>>>>>>>> be >>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a screw. >>>>>>>>>> >>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of a big >>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in opposite >>>>>>>>>> directions so that the screws remain stationary. Then turn one >>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>> between >>>>>>>>>> the two big dies after enough of an impression has been made. >>>>>>>>>> Feed a >>>>>>>>>> new pre-screw in due time. I'd think one machine can then thread >>>>>>>>>> 36000 >>>>>>>>>> screws per hour easily.) >>>>>>>>>> >>>>>>>>>> Roger. >>>>>>>>>> >>>>>>>>>> (*) You can calculate the size of the required wheel by knowing >>>>>>>>>> howmany rotations of the screw you want between the dies (i.e. >>>>>>>>>> length >>>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>> +31-15-2049110 ** >>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>> 27239233 ** >>>>>>>>>> f equals m times a. When your f is steady, and your m is going >>>>>>>>>> down >>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the space >>>>>>>>>> shuttle. >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

The last part of the thread tapers down to the minor diameter just where the screw ends. You can see the crest is still intact but the diameter is smaller in the photo. Bevelling removes the crest of the last threads and looks different. [image: image.png] On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: > The pic is a alas too rubbish for me to tell what' going on, but it looks > like it might be like my screws, which have a beveled end, not the feature > you're describing. Note that it's a small bevel, like the size of one > thread, so it has the effect of cutting off part of the thread and could > produce the illusion of an intentional taper like you're describing. I > inspected my screws under 10x magnification to figure out what was going > on. > > On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: > >> [image: IMG_20230220_230829904.jpg] >> That is what it looks like to me. Excuse the rubbish photo, I only have a >> phone with me. >> >> This is my attempt to model what I see. >> >> [image: image.png] >> >> >> >> >> >> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: >> >>> I've never seen a higbee end either. But I've also never seen a machine >>> screw with a tapered thread like you are describing. You have screws where >>> there is a full thread that gradually disappears by decreasing radius into >>> the shaft, and it's not because of a small bevel on the end? Mine all have >>> the shaft beveled. >>> >>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >>> >>>> Yes. The only things I have bevelled are leadscrews and studding cut to >>>> length that I bevel myself on a grinder. I have never seen a higbee end. >>>> >>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>>> You have machine screws where the threads taper at the ends? Like I >>>>> said...mine don't do that. The end is just beveled. >>>>> >>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> I do it over half a turn because that is what my machine screws look >>>>>> like they do and that is what I am trying to realistically draw. >>>>>> >>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>> wrote: >>>>>> >>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>> this? I have two views for clarity: >>>>>>> >>>>>>> [image: image.png] >>>>>>> >>>>>>> >>>>>>> [image: image.png] >>>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>> >>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> wrote: >>>>>>> >>>>>>>> Tapered by making the thread diameter decrease until it is below >>>>>>>> the minor diameter and disappears. I do it linearly over half a turn but >>>>>>>> your bottle example was much less. >>>>>>>> >>>>>>>> Higbee removes the crests instead because the thread is already >>>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>> >>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and over >>>>>>>>> what length? In both directions or just one? And why is that clearly >>>>>>>>> optimal. >>>>>>>>> >>>>>>>>> >>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Thinking some more about it, I think higbee only makes sense when >>>>>>>>>> you have a thread already made and you want to clean up the end. The >>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>> >>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>> >>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano wrote: >>>>>>>>>>> > I looked for info on how screws are made and it sounds like the >>>>>>>>>>> > normal way is indeed to press them between a pair of flat dies. >>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>> >>>>>>>>>>> I checked out your link, because I didn't think the shape of a >>>>>>>>>>> screw >>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>> >>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>> hindsight >>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>> cannot be >>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a screw. >>>>>>>>>>> >>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of a >>>>>>>>>>> big >>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in opposite >>>>>>>>>>> directions so that the screws remain stationary. Then turn one >>>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>>> between >>>>>>>>>>> the two big dies after enough of an impression has been made. >>>>>>>>>>> Feed a >>>>>>>>>>> new pre-screw in due time. I'd think one machine can then thread >>>>>>>>>>> 36000 >>>>>>>>>>> screws per hour easily.) >>>>>>>>>>> >>>>>>>>>>> Roger. >>>>>>>>>>> >>>>>>>>>>> (*) You can calculate the size of the required wheel by knowing >>>>>>>>>>> howmany rotations of the screw you want between the dies (i.e. >>>>>>>>>>> length >>>>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>>> 27239233 ** >>>>>>>>>>> f equals m times a. When your f is steady, and your m is going >>>>>>>>>>> down >>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the space >>>>>>>>>>> shuttle. >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

Here is a slightly better picture of a screw I also took here when there was daylight, [image: IMG_20210115_123701878.jpg] On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: > The last part of the thread tapers down to the minor diameter just where > the screw ends. You can see the crest is still intact but the diameter is > smaller in the photo. > > Bevelling removes the crest of the last threads and looks different. > > [image: image.png] > > On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: > >> The pic is a alas too rubbish for me to tell what' going on, but it looks >> like it might be like my screws, which have a beveled end, not the feature >> you're describing. Note that it's a small bevel, like the size of one >> thread, so it has the effect of cutting off part of the thread and could >> produce the illusion of an intentional taper like you're describing. I >> inspected my screws under 10x magnification to figure out what was going >> on. >> >> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >> >>> [image: IMG_20230220_230829904.jpg] >>> That is what it looks like to me. Excuse the rubbish photo, I only have >>> a phone with me. >>> >>> This is my attempt to model what I see. >>> >>> [image: image.png] >>> >>> >>> >>> >>> >>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>>> I've never seen a higbee end either. But I've also never seen a >>>> machine screw with a tapered thread like you are describing. You have >>>> screws where there is a full thread that gradually disappears by decreasing >>>> radius into the shaft, and it's not because of a small bevel on the end? >>>> Mine all have the shaft beveled. >>>> >>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >>>> >>>>> Yes. The only things I have bevelled are leadscrews and studding cut >>>>> to length that I bevel myself on a grinder. I have never seen a higbee end. >>>>> >>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> wrote: >>>>> >>>>>> You have machine screws where the threads taper at the ends? Like I >>>>>> said...mine don't do that. The end is just beveled. >>>>>> >>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> wrote: >>>>>> >>>>>>> I do it over half a turn because that is what my machine screws look >>>>>>> like they do and that is what I am trying to realistically draw. >>>>>>> >>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>>> this? I have two views for clarity: >>>>>>>> >>>>>>>> [image: image.png] >>>>>>>> >>>>>>>> >>>>>>>> [image: image.png] >>>>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>> >>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Tapered by making the thread diameter decrease until it is below >>>>>>>>> the minor diameter and disappears. I do it linearly over half a turn but >>>>>>>>> your bottle example was much less. >>>>>>>>> >>>>>>>>> Higbee removes the crests instead because the thread is already >>>>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>> >>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and over >>>>>>>>>> what length? In both directions or just one? And why is that clearly >>>>>>>>>> optimal. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> Thinking some more about it, I think higbee only makes sense >>>>>>>>>>> when you have a thread already made and you want to clean up the end. The >>>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>>> >>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>> >>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano wrote: >>>>>>>>>>>> > I looked for info on how screws are made and it sounds like >>>>>>>>>>>> the >>>>>>>>>>>> > normal way is indeed to press them between a pair of flat >>>>>>>>>>>> dies. >>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>> >>>>>>>>>>>> I checked out your link, because I didn't think the shape of a >>>>>>>>>>>> screw >>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>> >>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>> hindsight >>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>> cannot be >>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a screw. >>>>>>>>>>>> >>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of a >>>>>>>>>>>> big >>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in opposite >>>>>>>>>>>> directions so that the screws remain stationary. Then turn one >>>>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>>>> between >>>>>>>>>>>> the two big dies after enough of an impression has been made. >>>>>>>>>>>> Feed a >>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>> thread 36000 >>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>> >>>>>>>>>>>> Roger. >>>>>>>>>>>> >>>>>>>>>>>> (*) You can calculate the size of the required wheel by knowing >>>>>>>>>>>> howmany rotations of the screw you want between the dies (i.e. >>>>>>>>>>>> length >>>>>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>>>> 27239233 ** >>>>>>>>>>>> f equals m times a. When your f is steady, and your m is going >>>>>>>>>>>> down >>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>> space shuttle. >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> >

     Roger.

I still can't tell what's going on in your pic, but your model image of beveling is wrong. It's got a crazy huge bevel that touches several threads. The bevel only hits one thread most of the time. Beveling looks a lot like your second pic. Here is beveling. It looks sort of like a decreasing crest height, but it is something different. (Now that I think about it, I'm really not sure what your thread model is. You think you have screws where the thread form shrinks in diameter but stays the same width? How would that be manufactured?) [image: image.png] On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: > Here is a slightly better picture of a screw I also took here when there > was daylight, > > [image: IMG_20210115_123701878.jpg] > > On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: > >> The last part of the thread tapers down to the minor diameter just where >> the screw ends. You can see the crest is still intact but the diameter is >> smaller in the photo. >> >> Bevelling removes the crest of the last threads and looks different. >> >> [image: image.png] >> >> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: >> >>> The pic is a alas too rubbish for me to tell what' going on, but it >>> looks like it might be like my screws, which have a beveled end, not the >>> feature you're describing. Note that it's a small bevel, like the size of >>> one thread, so it has the effect of cutting off part of the thread and >>> could produce the illusion of an intentional taper like you're describing. >>> I inspected my screws under 10x magnification to figure out what was going >>> on. >>> >>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >>> >>>> [image: IMG_20230220_230829904.jpg] >>>> That is what it looks like to me. Excuse the rubbish photo, I only have >>>> a phone with me. >>>> >>>> This is my attempt to model what I see. >>>> >>>> [image: image.png] >>>> >>>> >>>> >>>> >>>> >>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>>> I've never seen a higbee end either. But I've also never seen a >>>>> machine screw with a tapered thread like you are describing. You have >>>>> screws where there is a full thread that gradually disappears by decreasing >>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>> Mine all have the shaft beveled. >>>>> >>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> Yes. The only things I have bevelled are leadscrews and studding cut >>>>>> to length that I bevel myself on a grinder. I have never seen a higbee end. >>>>>> >>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>> wrote: >>>>>> >>>>>>> You have machine screws where the threads taper at the ends? Like I >>>>>>> said...mine don't do that. The end is just beveled. >>>>>>> >>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> wrote: >>>>>>> >>>>>>>> I do it over half a turn because that is what my machine screws >>>>>>>> look like they do and that is what I am trying to realistically draw. >>>>>>>> >>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>>>> this? I have two views for clarity: >>>>>>>>> >>>>>>>>> [image: image.png] >>>>>>>>> >>>>>>>>> >>>>>>>>> [image: image.png] >>>>>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>> >>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Tapered by making the thread diameter decrease until it is below >>>>>>>>>> the minor diameter and disappears. I do it linearly over half a turn but >>>>>>>>>> your bottle example was much less. >>>>>>>>>> >>>>>>>>>> Higbee removes the crests instead because the thread is already >>>>>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>> >>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and over >>>>>>>>>>> what length? In both directions or just one? And why is that clearly >>>>>>>>>>> optimal. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> Thinking some more about it, I think higbee only makes sense >>>>>>>>>>>> when you have a thread already made and you want to clean up the end. The >>>>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>>>> >>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano wrote: >>>>>>>>>>>>> > I looked for info on how screws are made and it sounds like >>>>>>>>>>>>> the >>>>>>>>>>>>> > normal way is indeed to press them between a pair of flat >>>>>>>>>>>>> dies. >>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>> >>>>>>>>>>>>> I checked out your link, because I didn't think the shape of a >>>>>>>>>>>>> screw >>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>> >>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>> hindsight >>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>>> cannot be >>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a screw. >>>>>>>>>>>>> >>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of a >>>>>>>>>>>>> big >>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in opposite >>>>>>>>>>>>> directions so that the screws remain stationary. Then turn one >>>>>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>>>>> between >>>>>>>>>>>>> the two big dies after enough of an impression has been made. >>>>>>>>>>>>> Feed a >>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>> >>>>>>>>>>>>> Roger. >>>>>>>>>>>>> >>>>>>>>>>>>> (*) You can calculate the size of the required wheel by knowing >>>>>>>>>>>>> howmany rotations of the screw you want between the dies (i.e. >>>>>>>>>>>>> length >>>>>>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>>>>>> >>>>>>>>>>>>> -- >>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>>>>> 27239233 ** >>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is going >>>>>>>>>>>>> down >>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>>> space shuttle. >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

It stays the same pitch but the visible width reduces because the wider part is below the surface. Bevelling makes a sharp edge but my screws don't have a sharp edge. The picture I posted was of leads screws, which do have bevelled ends and multistarts. On Tue, 21 Feb 2023 at 00:43, Adrian Mariano <avm4@cornell.edu> wrote: > I still can't tell what's going on in your pic, but your model image of > beveling is wrong. It's got a crazy huge bevel that touches several > threads. The bevel only hits one thread most of the time. Beveling looks > a lot like your second pic. Here is beveling. It looks sort of like a > decreasing crest height, but it is something different. (Now that I think > about it, I'm really not sure what your thread model is. You think you > have screws where the thread form shrinks in diameter but stays the same > width? How would that be manufactured?) > > [image: image.png] > > > On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: > >> Here is a slightly better picture of a screw I also took here when there >> was daylight, >> >> [image: IMG_20210115_123701878.jpg] >> >> On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: >> >>> The last part of the thread tapers down to the minor diameter just where >>> the screw ends. You can see the crest is still intact but the diameter is >>> smaller in the photo. >>> >>> Bevelling removes the crest of the last threads and looks different. >>> >>> [image: image.png] >>> >>> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>>> The pic is a alas too rubbish for me to tell what' going on, but it >>>> looks like it might be like my screws, which have a beveled end, not the >>>> feature you're describing. Note that it's a small bevel, like the size of >>>> one thread, so it has the effect of cutting off part of the thread and >>>> could produce the illusion of an intentional taper like you're describing. >>>> I inspected my screws under 10x magnification to figure out what was going >>>> on. >>>> >>>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >>>> >>>>> [image: IMG_20230220_230829904.jpg] >>>>> That is what it looks like to me. Excuse the rubbish photo, I only >>>>> have a phone with me. >>>>> >>>>> This is my attempt to model what I see. >>>>> >>>>> [image: image.png] >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> wrote: >>>>> >>>>>> I've never seen a higbee end either. But I've also never seen a >>>>>> machine screw with a tapered thread like you are describing. You have >>>>>> screws where there is a full thread that gradually disappears by decreasing >>>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>>> Mine all have the shaft beveled. >>>>>> >>>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >>>>>> >>>>>>> Yes. The only things I have bevelled are leadscrews and studding cut >>>>>>> to length that I bevel myself on a grinder. I have never seen a higbee end. >>>>>>> >>>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> You have machine screws where the threads taper at the ends? Like >>>>>>>> I said...mine don't do that. The end is just beveled. >>>>>>>> >>>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> I do it over half a turn because that is what my machine screws >>>>>>>>> look like they do and that is what I am trying to realistically draw. >>>>>>>>> >>>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>>>>> this? I have two views for clarity: >>>>>>>>>> >>>>>>>>>> [image: image.png] >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> [image: image.png] >>>>>>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>>> >>>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> Tapered by making the thread diameter decrease until it is below >>>>>>>>>>> the minor diameter and disappears. I do it linearly over half a turn but >>>>>>>>>>> your bottle example was much less. >>>>>>>>>>> >>>>>>>>>>> Higbee removes the crests instead because the thread is already >>>>>>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>>>>>> the tool radius. See https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>>> >>>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and over >>>>>>>>>>>> what length? In both directions or just one? And why is that clearly >>>>>>>>>>>> optimal. >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Thinking some more about it, I think higbee only makes sense >>>>>>>>>>>>> when you have a thread already made and you want to clean up the end. The >>>>>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano >>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>> > I looked for info on how screws are made and it sounds like >>>>>>>>>>>>>> the >>>>>>>>>>>>>> > normal way is indeed to press them between a pair of flat >>>>>>>>>>>>>> dies. >>>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>>> >>>>>>>>>>>>>> I checked out your link, because I didn't think the shape of >>>>>>>>>>>>>> a screw >>>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>>> hindsight >>>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>>>> cannot be >>>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a >>>>>>>>>>>>>> screw. >>>>>>>>>>>>>> >>>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of >>>>>>>>>>>>>> a big >>>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in >>>>>>>>>>>>>> opposite >>>>>>>>>>>>>> directions so that the screws remain stationary. Then turn >>>>>>>>>>>>>> one >>>>>>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>>>>>> between >>>>>>>>>>>>>> the two big dies after enough of an impression has been made. >>>>>>>>>>>>>> Feed a >>>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>>> >>>>>>>>>>>>>> Roger. >>>>>>>>>>>>>> >>>>>>>>>>>>>> (*) You can calculate the size of the required wheel by >>>>>>>>>>>>>> knowing >>>>>>>>>>>>>> howmany rotations of the screw you want between the dies >>>>>>>>>>>>>> (i.e. length >>>>>>>>>>>>>> of the trajectory from original cylinder to "finished screw" ) >>>>>>>>>>>>>> >>>>>>>>>>>>>> -- >>>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>>>>>> 27239233 ** >>>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is >>>>>>>>>>>>>> going down >>>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>>>> space shuttle. >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

To manufacture it I assume they press the screw between dies that have a taper at the bottom. On Tue, 21 Feb 2023 at 01:08, nop head <nop.head@gmail.com> wrote: > It stays the same pitch but the visible width reduces because the wider > part is below the surface. > > Bevelling makes a sharp edge but my screws don't have a sharp edge. The > picture I posted was of leads screws, which do have bevelled ends and > multistarts. > > On Tue, 21 Feb 2023 at 00:43, Adrian Mariano <avm4@cornell.edu> wrote: > >> I still can't tell what's going on in your pic, but your model image of >> beveling is wrong. It's got a crazy huge bevel that touches several >> threads. The bevel only hits one thread most of the time. Beveling looks >> a lot like your second pic. Here is beveling. It looks sort of like a >> decreasing crest height, but it is something different. (Now that I think >> about it, I'm really not sure what your thread model is. You think you >> have screws where the thread form shrinks in diameter but stays the same >> width? How would that be manufactured?) >> >> [image: image.png] >> >> >> On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: >> >>> Here is a slightly better picture of a screw I also took here when there >>> was daylight, >>> >>> [image: IMG_20210115_123701878.jpg] >>> >>> On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: >>> >>>> The last part of the thread tapers down to the minor diameter just >>>> where the screw ends. You can see the crest is still intact but the >>>> diameter is smaller in the photo. >>>> >>>> Bevelling removes the crest of the last threads and looks different. >>>> >>>> [image: image.png] >>>> >>>> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>>> The pic is a alas too rubbish for me to tell what' going on, but it >>>>> looks like it might be like my screws, which have a beveled end, not the >>>>> feature you're describing. Note that it's a small bevel, like the size of >>>>> one thread, so it has the effect of cutting off part of the thread and >>>>> could produce the illusion of an intentional taper like you're describing. >>>>> I inspected my screws under 10x magnification to figure out what was going >>>>> on. >>>>> >>>>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> [image: IMG_20230220_230829904.jpg] >>>>>> That is what it looks like to me. Excuse the rubbish photo, I only >>>>>> have a phone with me. >>>>>> >>>>>> This is my attempt to model what I see. >>>>>> >>>>>> [image: image.png] >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> >>>>>> wrote: >>>>>> >>>>>>> I've never seen a higbee end either. But I've also never seen a >>>>>>> machine screw with a tapered thread like you are describing. You have >>>>>>> screws where there is a full thread that gradually disappears by decreasing >>>>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>>>> Mine all have the shaft beveled. >>>>>>> >>>>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> wrote: >>>>>>> >>>>>>>> Yes. The only things I have bevelled are leadscrews and studding >>>>>>>> cut to length that I bevel myself on a grinder. I have never seen a higbee >>>>>>>> end. >>>>>>>> >>>>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> You have machine screws where the threads taper at the ends? Like >>>>>>>>> I said...mine don't do that. The end is just beveled. >>>>>>>>> >>>>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> I do it over half a turn because that is what my machine screws >>>>>>>>>> look like they do and that is what I am trying to realistically draw. >>>>>>>>>> >>>>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>>>>>> this? I have two views for clarity: >>>>>>>>>>> >>>>>>>>>>> [image: image.png] >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> [image: image.png] >>>>>>>>>>> Why would you want to extend the taper for a full half-turn. My >>>>>>>>>>> correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>>>> >>>>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> Tapered by making the thread diameter decrease until it is >>>>>>>>>>>> below the minor diameter and disappears. I do it linearly over half a turn >>>>>>>>>>>> but your bottle example was much less. >>>>>>>>>>>> >>>>>>>>>>>> Higbee removes the crests instead because the thread is already >>>>>>>>>>>> formed at the nominal diameter. It can either ramp down gradually or be >>>>>>>>>>>> completely removed with a rotary milling tool leaving a short ramp due to >>>>>>>>>>>> the tool radius. See >>>>>>>>>>>> https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>>>> >>>>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and >>>>>>>>>>>>> over what length? In both directions or just one? And why is that >>>>>>>>>>>>> clearly optimal. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> Thinking some more about it, I think higbee only makes sense >>>>>>>>>>>>>> when you have a thread already made and you want to clean up the end. The >>>>>>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> > I looked for info on how screws are made and it sounds >>>>>>>>>>>>>>> like the >>>>>>>>>>>>>>> > normal way is indeed to press them between a pair of flat >>>>>>>>>>>>>>> dies. >>>>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> I checked out your link, because I didn't think the shape of >>>>>>>>>>>>>>> a screw >>>>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>>>> hindsight >>>>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>>>>> cannot be >>>>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a >>>>>>>>>>>>>>> screw. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside of >>>>>>>>>>>>>>> a big >>>>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in >>>>>>>>>>>>>>> opposite >>>>>>>>>>>>>>> directions so that the screws remain stationary. Then turn >>>>>>>>>>>>>>> one >>>>>>>>>>>>>>> slightly faster so that after enough rotations it drops down >>>>>>>>>>>>>>> between >>>>>>>>>>>>>>> the two big dies after enough of an impression has been >>>>>>>>>>>>>>> made. Feed a >>>>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Roger. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> (*) You can calculate the size of the required wheel by >>>>>>>>>>>>>>> knowing >>>>>>>>>>>>>>> howmany rotations of the screw you want between the dies >>>>>>>>>>>>>>> (i.e. length >>>>>>>>>>>>>>> of the trajectory from original cylinder to "finished screw" >>>>>>>>>>>>>>> ) >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. KVK: >>>>>>>>>>>>>>> 27239233 ** >>>>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is >>>>>>>>>>>>>>> going down >>>>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>>>>> space shuttle. >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> >

     Roger.

Wouldn't you need a die that had inverse threads that got wider and wider? On Mon, Feb 20, 2023 at 8:11 PM nop head <nop.head@gmail.com> wrote: > To manufacture it I assume they press the screw between dies that have a > taper at the bottom. > > On Tue, 21 Feb 2023 at 01:08, nop head <nop.head@gmail.com> wrote: > >> It stays the same pitch but the visible width reduces because the wider >> part is below the surface. >> >> Bevelling makes a sharp edge but my screws don't have a sharp edge. The >> picture I posted was of leads screws, which do have bevelled ends and >> multistarts. >> >> On Tue, 21 Feb 2023 at 00:43, Adrian Mariano <avm4@cornell.edu> wrote: >> >>> I still can't tell what's going on in your pic, but your model image of >>> beveling is wrong. It's got a crazy huge bevel that touches several >>> threads. The bevel only hits one thread most of the time. Beveling looks >>> a lot like your second pic. Here is beveling. It looks sort of like a >>> decreasing crest height, but it is something different. (Now that I think >>> about it, I'm really not sure what your thread model is. You think you >>> have screws where the thread form shrinks in diameter but stays the same >>> width? How would that be manufactured?) >>> >>> [image: image.png] >>> >>> >>> On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: >>> >>>> Here is a slightly better picture of a screw I also took here when >>>> there was daylight, >>>> >>>> [image: IMG_20210115_123701878.jpg] >>>> >>>> On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: >>>> >>>>> The last part of the thread tapers down to the minor diameter just >>>>> where the screw ends. You can see the crest is still intact but the >>>>> diameter is smaller in the photo. >>>>> >>>>> Bevelling removes the crest of the last threads and looks different. >>>>> >>>>> [image: image.png] >>>>> >>>>> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> wrote: >>>>> >>>>>> The pic is a alas too rubbish for me to tell what' going on, but it >>>>>> looks like it might be like my screws, which have a beveled end, not the >>>>>> feature you're describing. Note that it's a small bevel, like the size of >>>>>> one thread, so it has the effect of cutting off part of the thread and >>>>>> could produce the illusion of an intentional taper like you're describing. >>>>>> I inspected my screws under 10x magnification to figure out what was going >>>>>> on. >>>>>> >>>>>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >>>>>> >>>>>>> [image: IMG_20230220_230829904.jpg] >>>>>>> That is what it looks like to me. Excuse the rubbish photo, I only >>>>>>> have a phone with me. >>>>>>> >>>>>>> This is my attempt to model what I see. >>>>>>> >>>>>>> [image: image.png] >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> I've never seen a higbee end either. But I've also never seen a >>>>>>>> machine screw with a tapered thread like you are describing. You have >>>>>>>> screws where there is a full thread that gradually disappears by decreasing >>>>>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>>>>> Mine all have the shaft beveled. >>>>>>>> >>>>>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Yes. The only things I have bevelled are leadscrews and studding >>>>>>>>> cut to length that I bevel myself on a grinder. I have never seen a higbee >>>>>>>>> end. >>>>>>>>> >>>>>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> You have machine screws where the threads taper at the ends? >>>>>>>>>> Like I said...mine don't do that. The end is just beveled. >>>>>>>>>> >>>>>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> I do it over half a turn because that is what my machine screws >>>>>>>>>>> look like they do and that is what I am trying to realistically draw. >>>>>>>>>>> >>>>>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> So lineiar decrease in diameter of the thread? Something like >>>>>>>>>>>> this? I have two views for clarity: >>>>>>>>>>>> >>>>>>>>>>>> [image: image.png] >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> [image: image.png] >>>>>>>>>>>> Why would you want to extend the taper for a full half-turn. >>>>>>>>>>>> My correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>>>>> >>>>>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Tapered by making the thread diameter decrease until it is >>>>>>>>>>>>> below the minor diameter and disappears. I do it linearly over half a turn >>>>>>>>>>>>> but your bottle example was much less. >>>>>>>>>>>>> >>>>>>>>>>>>> Higbee removes the crests instead because the thread is >>>>>>>>>>>>> already formed at the nominal diameter. It can either ramp down gradually >>>>>>>>>>>>> or be completely removed with a rotary milling tool leaving a short ramp >>>>>>>>>>>>> due to the tool radius. See >>>>>>>>>>>>> https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and >>>>>>>>>>>>>> over what length? In both directions or just one? And why is that >>>>>>>>>>>>>> clearly optimal. >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> Thinking some more about it, I think higbee only makes sense >>>>>>>>>>>>>>> when you have a thread already made and you want to clean up the end. The >>>>>>>>>>>>>>> optimal end shape is simply tapered when you can mould it or 3D print it. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano >>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>> > I looked for info on how screws are made and it sounds >>>>>>>>>>>>>>>> like the >>>>>>>>>>>>>>>> > normal way is indeed to press them between a pair of flat >>>>>>>>>>>>>>>> dies. >>>>>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I checked out your link, because I didn't think the shape >>>>>>>>>>>>>>>> of a screw >>>>>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>>>>> hindsight >>>>>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>>>>>> cannot be >>>>>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a >>>>>>>>>>>>>>>> screw. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside >>>>>>>>>>>>>>>> of a big >>>>>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in >>>>>>>>>>>>>>>> opposite >>>>>>>>>>>>>>>> directions so that the screws remain stationary. Then turn >>>>>>>>>>>>>>>> one >>>>>>>>>>>>>>>> slightly faster so that after enough rotations it drops >>>>>>>>>>>>>>>> down between >>>>>>>>>>>>>>>> the two big dies after enough of an impression has been >>>>>>>>>>>>>>>> made. Feed a >>>>>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Roger. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> (*) You can calculate the size of the required wheel by >>>>>>>>>>>>>>>> knowing >>>>>>>>>>>>>>>> howmany rotations of the screw you want between the dies >>>>>>>>>>>>>>>> (i.e. length >>>>>>>>>>>>>>>> of the trajectory from original cylinder to "finished >>>>>>>>>>>>>>>> screw" ) >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. >>>>>>>>>>>>>>>> KVK: 27239233 ** >>>>>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is >>>>>>>>>>>>>>>> going down >>>>>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>>>>>> space shuttle. >>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

Yes it would need to get wider so the gap gets smaller. It would be difficult to make with a lathe or a circular die, hence why I think higbee exists. You need a rotary tool in the toolpost to make the abrupt version but the gradual ramp down can be created with a flat nosed grooving tool on a CNC lathe. I have a CNC lathe at my summer residence so I might have a go sometime. The last thread I CNC cut I started with a chamfer before single point threading. But with a chamfer you get a thin edge where the chamfer intersects the threads crest. On Tue, 21 Feb 2023 at 01:51, Adrian Mariano <avm4@cornell.edu> wrote: > Wouldn't you need a die that had inverse threads that got wider and > wider? > > On Mon, Feb 20, 2023 at 8:11 PM nop head <nop.head@gmail.com> wrote: > >> To manufacture it I assume they press the screw between dies that have a >> taper at the bottom. >> >> On Tue, 21 Feb 2023 at 01:08, nop head <nop.head@gmail.com> wrote: >> >>> It stays the same pitch but the visible width reduces because the wider >>> part is below the surface. >>> >>> Bevelling makes a sharp edge but my screws don't have a sharp edge. The >>> picture I posted was of leads screws, which do have bevelled ends and >>> multistarts. >>> >>> On Tue, 21 Feb 2023 at 00:43, Adrian Mariano <avm4@cornell.edu> wrote: >>> >>>> I still can't tell what's going on in your pic, but your model image of >>>> beveling is wrong. It's got a crazy huge bevel that touches several >>>> threads. The bevel only hits one thread most of the time. Beveling looks >>>> a lot like your second pic. Here is beveling. It looks sort of like a >>>> decreasing crest height, but it is something different. (Now that I think >>>> about it, I'm really not sure what your thread model is. You think you >>>> have screws where the thread form shrinks in diameter but stays the same >>>> width? How would that be manufactured?) >>>> >>>> [image: image.png] >>>> >>>> >>>> On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: >>>> >>>>> Here is a slightly better picture of a screw I also took here when >>>>> there was daylight, >>>>> >>>>> [image: IMG_20210115_123701878.jpg] >>>>> >>>>> On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> The last part of the thread tapers down to the minor diameter just >>>>>> where the screw ends. You can see the crest is still intact but the >>>>>> diameter is smaller in the photo. >>>>>> >>>>>> Bevelling removes the crest of the last threads and looks different. >>>>>> >>>>>> [image: image.png] >>>>>> >>>>>> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> >>>>>> wrote: >>>>>> >>>>>>> The pic is a alas too rubbish for me to tell what' going on, but it >>>>>>> looks like it might be like my screws, which have a beveled end, not the >>>>>>> feature you're describing. Note that it's a small bevel, like the size of >>>>>>> one thread, so it has the effect of cutting off part of the thread and >>>>>>> could produce the illusion of an intentional taper like you're describing. >>>>>>> I inspected my screws under 10x magnification to figure out what was going >>>>>>> on. >>>>>>> >>>>>>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> wrote: >>>>>>> >>>>>>>> [image: IMG_20230220_230829904.jpg] >>>>>>>> That is what it looks like to me. Excuse the rubbish photo, I only >>>>>>>> have a phone with me. >>>>>>>> >>>>>>>> This is my attempt to model what I see. >>>>>>>> >>>>>>>> [image: image.png] >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> I've never seen a higbee end either. But I've also never seen a >>>>>>>>> machine screw with a tapered thread like you are describing. You have >>>>>>>>> screws where there is a full thread that gradually disappears by decreasing >>>>>>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>>>>>> Mine all have the shaft beveled. >>>>>>>>> >>>>>>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Yes. The only things I have bevelled are leadscrews and studding >>>>>>>>>> cut to length that I bevel myself on a grinder. I have never seen a higbee >>>>>>>>>> end. >>>>>>>>>> >>>>>>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> You have machine screws where the threads taper at the ends? >>>>>>>>>>> Like I said...mine don't do that. The end is just beveled. >>>>>>>>>>> >>>>>>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> I do it over half a turn because that is what my machine screws >>>>>>>>>>>> look like they do and that is what I am trying to realistically draw. >>>>>>>>>>>> >>>>>>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> So lineiar decrease in diameter of the thread? Something >>>>>>>>>>>>> like this? I have two views for clarity: >>>>>>>>>>>>> >>>>>>>>>>>>> [image: image.png] >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> [image: image.png] >>>>>>>>>>>>> Why would you want to extend the taper for a full half-turn. >>>>>>>>>>>>> My correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> Tapered by making the thread diameter decrease until it is >>>>>>>>>>>>>> below the minor diameter and disappears. I do it linearly over half a turn >>>>>>>>>>>>>> but your bottle example was much less. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Higbee removes the crests instead because the thread is >>>>>>>>>>>>>> already formed at the nominal diameter. It can either ramp down gradually >>>>>>>>>>>>>> or be completely removed with a rotary milling tool leaving a short ramp >>>>>>>>>>>>>> due to the tool radius. See >>>>>>>>>>>>>> https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano < >>>>>>>>>>>>>> avm4@cornell.edu> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and >>>>>>>>>>>>>>> over what length? In both directions or just one? And why is that >>>>>>>>>>>>>>> clearly optimal. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head <nop.head@gmail.com> >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Thinking some more about it, I think higbee only makes >>>>>>>>>>>>>>>> sense when you have a thread already made and you want to clean up the end. >>>>>>>>>>>>>>>> The optimal end shape is simply tapered when you can mould it or 3D print >>>>>>>>>>>>>>>> it. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano >>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>> > I looked for info on how screws are made and it sounds >>>>>>>>>>>>>>>>> like the >>>>>>>>>>>>>>>>> > normal way is indeed to press them between a pair of >>>>>>>>>>>>>>>>> flat dies. >>>>>>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> I checked out your link, because I didn't think the shape >>>>>>>>>>>>>>>>> of a screw >>>>>>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>>>>>> hindsight >>>>>>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure they >>>>>>>>>>>>>>>>> cannot be >>>>>>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a >>>>>>>>>>>>>>>>> screw. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside >>>>>>>>>>>>>>>>> of a big >>>>>>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in >>>>>>>>>>>>>>>>> opposite >>>>>>>>>>>>>>>>> directions so that the screws remain stationary. Then >>>>>>>>>>>>>>>>> turn one >>>>>>>>>>>>>>>>> slightly faster so that after enough rotations it drops >>>>>>>>>>>>>>>>> down between >>>>>>>>>>>>>>>>> the two big dies after enough of an impression has been >>>>>>>>>>>>>>>>> made. Feed a >>>>>>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Roger. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> (*) You can calculate the size of the required wheel by >>>>>>>>>>>>>>>>> knowing >>>>>>>>>>>>>>>>> howmany rotations of the screw you want between the dies >>>>>>>>>>>>>>>>> (i.e. length >>>>>>>>>>>>>>>>> of the trajectory from original cylinder to "finished >>>>>>>>>>>>>>>>> screw" ) >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ ** >>>>>>>>>>>>>>>>> +31-15-2049110 ** >>>>>>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. >>>>>>>>>>>>>>>>> KVK: 27239233 ** >>>>>>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is >>>>>>>>>>>>>>>>> going down >>>>>>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up the >>>>>>>>>>>>>>>>> space shuttle. >>>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> OpenSCAD mailing list >>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>> >>>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>>> OpenSCAD mailing list >>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>> >>> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

     Roger.

Actually the die top surfaces would be parallel as the minor diameter doesn't change. The depth of the groves would have to decrease at the end. On Tue, 21 Feb 2023 at 08:29, nop head <nop.head@gmail.com> wrote: > Yes it would need to get wider so the gap gets smaller. > > It would be difficult to make with a lathe or a circular die, hence why I > think higbee exists. You need a rotary tool in the toolpost to make the > abrupt version but the gradual ramp down can be created with a flat nosed > grooving tool on a CNC lathe. > > I have a CNC lathe at my summer residence so I might have a go sometime. > The last thread I CNC cut I started with a chamfer before single point > threading. But with a chamfer you get a thin edge where the chamfer > intersects the threads crest. > > On Tue, 21 Feb 2023 at 01:51, Adrian Mariano <avm4@cornell.edu> wrote: > >> Wouldn't you need a die that had inverse threads that got wider and >> wider? >> >> On Mon, Feb 20, 2023 at 8:11 PM nop head <nop.head@gmail.com> wrote: >> >>> To manufacture it I assume they press the screw between dies that have a >>> taper at the bottom. >>> >>> On Tue, 21 Feb 2023 at 01:08, nop head <nop.head@gmail.com> wrote: >>> >>>> It stays the same pitch but the visible width reduces because the wider >>>> part is below the surface. >>>> >>>> Bevelling makes a sharp edge but my screws don't have a sharp edge. The >>>> picture I posted was of leads screws, which do have bevelled ends and >>>> multistarts. >>>> >>>> On Tue, 21 Feb 2023 at 00:43, Adrian Mariano <avm4@cornell.edu> wrote: >>>> >>>>> I still can't tell what's going on in your pic, but your model image >>>>> of beveling is wrong. It's got a crazy huge bevel that touches several >>>>> threads. The bevel only hits one thread most of the time. Beveling looks >>>>> a lot like your second pic. Here is beveling. It looks sort of like a >>>>> decreasing crest height, but it is something different. (Now that I think >>>>> about it, I'm really not sure what your thread model is. You think you >>>>> have screws where the thread form shrinks in diameter but stays the same >>>>> width? How would that be manufactured?) >>>>> >>>>> [image: image.png] >>>>> >>>>> >>>>> On Mon, Feb 20, 2023 at 6:40 PM nop head <nop.head@gmail.com> wrote: >>>>> >>>>>> Here is a slightly better picture of a screw I also took here when >>>>>> there was daylight, >>>>>> >>>>>> [image: IMG_20210115_123701878.jpg] >>>>>> >>>>>> On Mon, 20 Feb 2023 at 23:30, nop head <nop.head@gmail.com> wrote: >>>>>> >>>>>>> The last part of the thread tapers down to the minor diameter just >>>>>>> where the screw ends. You can see the crest is still intact but the >>>>>>> diameter is smaller in the photo. >>>>>>> >>>>>>> Bevelling removes the crest of the last threads and looks different. >>>>>>> >>>>>>> [image: image.png] >>>>>>> >>>>>>> On Mon, 20 Feb 2023 at 23:23, Adrian Mariano <avm4@cornell.edu> >>>>>>> wrote: >>>>>>> >>>>>>>> The pic is a alas too rubbish for me to tell what' going on, but it >>>>>>>> looks like it might be like my screws, which have a beveled end, not the >>>>>>>> feature you're describing. Note that it's a small bevel, like the size of >>>>>>>> one thread, so it has the effect of cutting off part of the thread and >>>>>>>> could produce the illusion of an intentional taper like you're describing. >>>>>>>> I inspected my screws under 10x magnification to figure out what was going >>>>>>>> on. >>>>>>>> >>>>>>>> On Mon, Feb 20, 2023 at 6:17 PM nop head <nop.head@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> [image: IMG_20230220_230829904.jpg] >>>>>>>>> That is what it looks like to me. Excuse the rubbish photo, I only >>>>>>>>> have a phone with me. >>>>>>>>> >>>>>>>>> This is my attempt to model what I see. >>>>>>>>> >>>>>>>>> [image: image.png] >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Mon, 20 Feb 2023 at 23:06, Adrian Mariano <avm4@cornell.edu> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> I've never seen a higbee end either. But I've also never seen a >>>>>>>>>> machine screw with a tapered thread like you are describing. You have >>>>>>>>>> screws where there is a full thread that gradually disappears by decreasing >>>>>>>>>> radius into the shaft, and it's not because of a small bevel on the end? >>>>>>>>>> Mine all have the shaft beveled. >>>>>>>>>> >>>>>>>>>> On Mon, Feb 20, 2023 at 6:02 PM nop head <nop.head@gmail.com> >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> Yes. The only things I have bevelled are leadscrews and studding >>>>>>>>>>> cut to length that I bevel myself on a grinder. I have never seen a higbee >>>>>>>>>>> end. >>>>>>>>>>> >>>>>>>>>>> On Mon, 20 Feb 2023 at 22:37, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> You have machine screws where the threads taper at the ends? >>>>>>>>>>>> Like I said...mine don't do that. The end is just beveled. >>>>>>>>>>>> >>>>>>>>>>>> On Mon, Feb 20, 2023 at 5:33 PM nop head <nop.head@gmail.com> >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> I do it over half a turn because that is what my machine >>>>>>>>>>>>> screws look like they do and that is what I am trying to realistically draw. >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, 20 Feb 2023 at 22:28, Adrian Mariano <avm4@cornell.edu> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> So lineiar decrease in diameter of the thread? Something >>>>>>>>>>>>>> like this? I have two views for clarity: >>>>>>>>>>>>>> >>>>>>>>>>>>>> [image: image.png] >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> [image: image.png] >>>>>>>>>>>>>> Why would you want to extend the taper for a full half-turn. >>>>>>>>>>>>>> My correspondent was a little self-inconsistent, but suggested a *much* >>>>>>>>>>>>>> shorter length, and it seems like a shorter length is better. In fact, I >>>>>>>>>>>>>> wonder if really very short is best. Doesn't the section where the >>>>>>>>>>>>>> diameter of the thread is reduced enable you to hop over it to >>>>>>>>>>>>>> crossthread? It seems like the abrupt end of the threads is the key to >>>>>>>>>>>>>> success here: you can't hop into the next thread because you have a full >>>>>>>>>>>>>> thread in the way. That's why I wonder if tapering is even a good idea as >>>>>>>>>>>>>> compared to a more abrupt stop. On the other hand, maybe the bottle makers >>>>>>>>>>>>>> know what they're doing? Their standard doesn't specify this, but in >>>>>>>>>>>>>> their drawings it looks like about a quarter of a right angle, so ~20 >>>>>>>>>>>>>> degrees. My correspondent seemed to think it should depend on the pitch >>>>>>>>>>>>>> size of the threads, and nothing to do with angle, though. >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 5:00 PM nop head <nop.head@gmail.com> >>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> Tapered by making the thread diameter decrease until it is >>>>>>>>>>>>>>> below the minor diameter and disappears. I do it linearly over half a turn >>>>>>>>>>>>>>> but your bottle example was much less. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Higbee removes the crests instead because the thread is >>>>>>>>>>>>>>> already formed at the nominal diameter. It can either ramp down gradually >>>>>>>>>>>>>>> or be completely removed with a rotary milling tool leaving a short ramp >>>>>>>>>>>>>>> due to the tool radius. See >>>>>>>>>>>>>>> https://www.youtube.com/watch?v=MUojDLAaBiE >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 21:49, Adrian Mariano < >>>>>>>>>>>>>>> avm4@cornell.edu> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> So "simply tapered" is not well-defined. Tapered how, and >>>>>>>>>>>>>>>> over what length? In both directions or just one? And why is that >>>>>>>>>>>>>>>> clearly optimal. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 9:55 AM nop head < >>>>>>>>>>>>>>>> nop.head@gmail.com> wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Thinking some more about it, I think higbee only makes >>>>>>>>>>>>>>>>> sense when you have a thread already made and you want to clean up the end. >>>>>>>>>>>>>>>>> The optimal end shape is simply tapered when you can mould it or 3D print >>>>>>>>>>>>>>>>> it. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> On Mon, 20 Feb 2023 at 14:45, Rogier Wolff < >>>>>>>>>>>>>>>>> R.E.Wolff@bitwizard.nl> wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> On Mon, Feb 20, 2023 at 06:37:37AM -0500, Adrian Mariano >>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>> > I looked for info on how screws are made and it sounds >>>>>>>>>>>>>>>>>> like the >>>>>>>>>>>>>>>>>> > normal way is indeed to press them between a pair of >>>>>>>>>>>>>>>>>> flat dies. >>>>>>>>>>>>>>>>>> > This process could not make a higbee end. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> I checked out your link, because I didn't think the shape >>>>>>>>>>>>>>>>>> of a screw >>>>>>>>>>>>>>>>>> could be pressed between two dies. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Turns out the ROLL the pre-screw between the two dies. In >>>>>>>>>>>>>>>>>> hindsight >>>>>>>>>>>>>>>>>> The hint was there with the /flat/ dies, but for sure >>>>>>>>>>>>>>>>>> they cannot be >>>>>>>>>>>>>>>>>> FLAT because that'd make them "cylindrical" instead of a >>>>>>>>>>>>>>>>>> screw. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> (If I'm honest... I'd make the dies round (on the outside >>>>>>>>>>>>>>>>>> of a big >>>>>>>>>>>>>>>>>> wheel (*)) so that you can rotate them. rotate them in >>>>>>>>>>>>>>>>>> opposite >>>>>>>>>>>>>>>>>> directions so that the screws remain stationary. Then >>>>>>>>>>>>>>>>>> turn one >>>>>>>>>>>>>>>>>> slightly faster so that after enough rotations it drops >>>>>>>>>>>>>>>>>> down between >>>>>>>>>>>>>>>>>> the two big dies after enough of an impression has been >>>>>>>>>>>>>>>>>> made. Feed a >>>>>>>>>>>>>>>>>> new pre-screw in due time. I'd think one machine can then >>>>>>>>>>>>>>>>>> thread 36000 >>>>>>>>>>>>>>>>>> screws per hour easily.) >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Roger. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> (*) You can calculate the size of the required wheel by >>>>>>>>>>>>>>>>>> knowing >>>>>>>>>>>>>>>>>> howmany rotations of the screw you want between the dies >>>>>>>>>>>>>>>>>> (i.e. length >>>>>>>>>>>>>>>>>> of the trajectory from original cylinder to "finished >>>>>>>>>>>>>>>>>> screw" ) >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>>>> ** R.E.Wolff@BitWizard.nl ** https://www.BitWizard.nl/ >>>>>>>>>>>>>>>>>> ** +31-15-2049110 ** >>>>>>>>>>>>>>>>>> ** Delftechpark 11 2628 XJ Delft, The Netherlands. >>>>>>>>>>>>>>>>>> KVK: 27239233 ** >>>>>>>>>>>>>>>>>> f equals m times a. When your f is steady, and your m is >>>>>>>>>>>>>>>>>> going down >>>>>>>>>>>>>>>>>> your a is going up. -- Chris Hadfield about flying up >>>>>>>>>>>>>>>>>> the space shuttle. >>>>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>>> >>>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>>> >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>>> >>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>>> To unsubscribe send an email to >>>>>>>>>>>> discuss-leave@lists.openscad.org >>>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> OpenSCAD mailing list >>>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> OpenSCAD mailing list >>>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> OpenSCAD mailing list >>>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OpenSCAD mailing list >>>>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>>>> >>>>>>> _______________________________________________ >>>>>> OpenSCAD mailing list >>>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>>> >>>>> _______________________________________________ >>>>> OpenSCAD mailing list >>>>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>>>> >>>> _______________________________________________ >>> OpenSCAD mailing list >>> To unsubscribe send an email to discuss-leave@lists.openscad.org >>> >> _______________________________________________ >> OpenSCAD mailing list >> To unsubscribe send an email to discuss-leave@lists.openscad.org >> >