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specifications for JIS and square/Robertson screw heads?

AM
Adrian Mariano
Wed, Sep 22, 2021 11:46 AM

I'm wondering if anybody knows a source for full specs for the JIS
cross-type screw recess or the square / Robertson recess.  I've seen
some information on the JIS, but not enough detail to actually build a
model.  In the case of square recess I've found a couple documents
that give some information but they don't indicate what the taper is,
and they give dimensions that are inconsistent with my actual square
drive hardware (drivers and screws).

I'm wondering if anybody knows a source for full specs for the JIS cross-type screw recess or the square / Robertson recess. I've seen some information on the JIS, but not enough detail to actually build a model. In the case of square recess I've found a couple documents that give some information but they don't indicate what the taper is, and they give dimensions that are inconsistent with my actual square drive hardware (drivers and screws).
L
larry
Wed, Sep 22, 2021 1:39 PM

On Wed, 2021-09-22 at 07:46 -0400, Adrian Mariano wrote:

I'm wondering if anybody knows a source for full specs for the JIS
cross-type screw recess or the square / Robertson recess.  I've seen
some information on the JIS, but not enough detail to actually build
a model.  In the case of square recess I've found a couple documents
that give some information but they don't indicate what the taper is,
and they give dimensions that are inconsistent with my actual square
drive hardware (drivers and screws).

I gather you are aware that a 'square drive' and a Robertson are
different animals. Which are you measuring?

On Wed, 2021-09-22 at 07:46 -0400, Adrian Mariano wrote: > I'm wondering if anybody knows a source for full specs for the JIS > cross-type screw recess or the square / Robertson recess. I've seen > some information on the JIS, but not enough detail to actually build > a model. In the case of square recess I've found a couple documents > that give some information but they don't indicate what the taper is, > and they give dimensions that are inconsistent with my actual square > drive hardware (drivers and screws). I gather you are aware that a 'square drive' and a Robertson are different animals. Which are you measuring?
RW
Ray West
Wed, Sep 22, 2021 2:01 PM

The wiki is a good starting point
https://en.wikipedia.org/wiki/Robertson_screwdriver but we need a sort
of modern  international Joseph Whitworth  to sort it all out. Some
suppliers/manufacturers will have cad files, e.g. McMaster-Carr, but not
sure if they go to detail of screws.

On 22/09/2021 12:46, Adrian Mariano wrote:

I'm wondering if anybody knows a source for full specs for the JIS
cross-type screw recess or the square / Robertson recess.  I've seen
some information on the JIS, but not enough detail to actually build a
model.  In the case of square recess I've found a couple documents
that give some information but they don't indicate what the taper is,
and they give dimensions that are inconsistent with my actual square
drive hardware (drivers and screws).


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The wiki is a good starting point https://en.wikipedia.org/wiki/Robertson_screwdriver but we need a sort of modern  international Joseph Whitworth  to sort it all out. Some suppliers/manufacturers will have cad files, e.g. McMaster-Carr, but not sure if they go to detail of screws. On 22/09/2021 12:46, Adrian Mariano wrote: > I'm wondering if anybody knows a source for full specs for the JIS > cross-type screw recess or the square / Robertson recess. I've seen > some information on the JIS, but not enough detail to actually build a > model. In the case of square recess I've found a couple documents > that give some information but they don't indicate what the taper is, > and they give dimensions that are inconsistent with my actual square > drive hardware (drivers and screws). > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org
AM
Adrian Mariano
Wed, Sep 22, 2021 3:50 PM

I am aware that some people claim that square drive and Robertson are
different.  It's not clear that this is true.  The supposed difference
is whether the recess is tapered.  If you like wikipedia: "A
Robertson screw, also known as a square or Scrulox screw drive, is
specified as ANSI Type III Square Center".  Sounds like one animal.
Others have suggested that there are not two different standards but
just badly made square drive screws/drivers and well made ones, a
situation one might also encounter in the land of Phillips or slotted
screws.

People are making the screws and drivers.  They seem to all work
together.  (Well, I can't speak personally about JIS, but certainly
for others, including square drive.)  I have gotten square drive stuff
from McFeelys, from McMaster, and even Home Depot, and it all works
together.  And they display the property that a screw sticks firmly
onto the driver, even with the driver pointing down.  This doesn't
happen by accident.  There must be a standard document that describes
these --- presumably the ANSI Type III Square Center document.

No, the wiki page on Square Drive (which I quoted for you above) is
not a starting point.  It leads nowhere.  Just to be clear, this is
what a spec document looks like:

https://www.fasteners.eu/tech-info/ISO/4757/

It has for Phillips all the dimensions and angles you need to define
the shape of the recess.  I have not managed to find such a document
for JIS or for square/Robertson...at least not for less than US$78.

I found one document for square drive that as I noted above has
incomplete information (no taper angle, for example, or indication of
what the point looks like--a cone, maybe?) and dimensions that seem
inconsistent with reality:
https://www.aspenfasteners.com/content/pdf/square_drive_specification.pdf.
This same data appears in a few other places as well.  I noticed that
McFeelys at least at some point listed the same dimensions that are in
this table as the driver width.  Though even so, none of my
drivers---not even the ones I bought from McFeelys---are that small.

On Wed, Sep 22, 2021 at 10:01 AM Ray West raywest@raywest.com wrote:

The wiki is a good starting point
https://en.wikipedia.org/wiki/Robertson_screwdriver but we need a sort
of modern  international Joseph Whitworth  to sort it all out. Some
suppliers/manufacturers will have cad files, e.g. McMaster-Carr, but not
sure if they go to detail of screws.

On 22/09/2021 12:46, Adrian Mariano wrote:

I'm wondering if anybody knows a source for full specs for the JIS
cross-type screw recess or the square / Robertson recess.  I've seen
some information on the JIS, but not enough detail to actually build a
model.  In the case of square recess I've found a couple documents
that give some information but they don't indicate what the taper is,
and they give dimensions that are inconsistent with my actual square
drive hardware (drivers and screws).


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To unsubscribe send an email to discuss-leave@lists.openscad.org


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To unsubscribe send an email to discuss-leave@lists.openscad.org

I am aware that some people claim that square drive and Robertson are different. It's not clear that this is true. The supposed difference is whether the recess is tapered. If you like wikipedia: "A Robertson screw, also known as a square or Scrulox screw drive, is specified as ANSI Type III Square Center". Sounds like one animal. Others have suggested that there are not two different standards but just badly made square drive screws/drivers and well made ones, a situation one might also encounter in the land of Phillips or slotted screws. People are making the screws and drivers. They seem to all work together. (Well, I can't speak personally about JIS, but certainly for others, including square drive.) I have gotten square drive stuff from McFeelys, from McMaster, and even Home Depot, and it all works together. And they display the property that a screw sticks firmly onto the driver, even with the driver pointing down. This doesn't happen by accident. There must be a standard document that describes these --- presumably the ANSI Type III Square Center document. No, the wiki page on Square Drive (which I quoted for you above) is not a starting point. It leads nowhere. Just to be clear, this is what a spec document looks like: https://www.fasteners.eu/tech-info/ISO/4757/ It has for Phillips all the dimensions and angles you need to define the shape of the recess. I have not managed to find such a document for JIS or for square/Robertson...at least not for less than US$78. I found one document for square drive that as I noted above has incomplete information (no taper angle, for example, or indication of what the point looks like--a cone, maybe?) and dimensions that seem inconsistent with reality: https://www.aspenfasteners.com/content/pdf/square_drive_specification.pdf. This same data appears in a few other places as well. I noticed that McFeelys at least at some point listed the same dimensions that are in this table as the *driver* width. Though even so, none of my drivers---not even the ones I bought from McFeelys---are that small. On Wed, Sep 22, 2021 at 10:01 AM Ray West <raywest@raywest.com> wrote: > > The wiki is a good starting point > https://en.wikipedia.org/wiki/Robertson_screwdriver but we need a sort > of modern international Joseph Whitworth to sort it all out. Some > suppliers/manufacturers will have cad files, e.g. McMaster-Carr, but not > sure if they go to detail of screws. > > On 22/09/2021 12:46, Adrian Mariano wrote: > > I'm wondering if anybody knows a source for full specs for the JIS > > cross-type screw recess or the square / Robertson recess. I've seen > > some information on the JIS, but not enough detail to actually build a > > model. In the case of square recess I've found a couple documents > > that give some information but they don't indicate what the taper is, > > and they give dimensions that are inconsistent with my actual square > > drive hardware (drivers and screws). > > _______________________________________________ > > 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
RW
Ray West
Wed, Sep 22, 2021 4:21 PM

On 22/09/2021 16:50, Adrian Mariano wrote:

They seem to all work
together.  (Well, I can't speak personally about JIS, but certainly
for others, including square drive.)  I have gotten square drive stuff
from McFeelys, from McMaster, and even Home Depot, and it all works
together.

It's also possible to 'fit' some metric sized nuts to imperial threads,
use philips screw divers in pozidriv slots, and flatbladed screwdrivers
as chisels. It does not mean there are or not specifications/standards
for any or all of it.

http://www.japanesescrews.com/about-us.html  shows pozidriv heads, but
their pages only mention philips. It all fits where it touches.

On 22/09/2021 16:50, Adrian Mariano wrote: > They seem to all work > together. (Well, I can't speak personally about JIS, but certainly > for others, including square drive.) I have gotten square drive stuff > from McFeelys, from McMaster, and even Home Depot, and it all works > together. It's also possible to 'fit' some metric sized nuts to imperial threads, use philips screw divers in pozidriv slots, and flatbladed screwdrivers as chisels. It does not mean there are or not specifications/standards for any or all of it. http://www.japanesescrews.com/about-us.html  shows pozidriv heads, but their pages only mention philips. It all fits where it touches.
AM
Adrian Mariano
Wed, Sep 22, 2021 5:01 PM

I'm not sure what you're trying to say.  I don't think that my square
drive tooling is at all analogous to "fitting" metric and UTS threads
to each other.  I think the square drivers have been designed
according to a consistent standard and they therefore all work
interchangeably.  It's not coincidence that all my drivers are within
.001 inches of each other across several brands.  I see no compelling
reason to hypothesize that a bunch of tools that work fine together
and are the same size are misfits, nor is there any "forcing" going on
here.  However, the recess size from the spec reference I found is
smaller than all of my drivers, so if I had a screw with that recess
none of my drivers would fit.  My drivers fit great in my square drive
screws.  So something's not right with that spec data.

I've never encountered a Pozi screw, but I've occasionally
accidentally tried a Pozi bit in a Phillips recess and it does not
fit.  (I should throw away all the pozi bits.)  Reportedly you'll
also fail if you try to use a Phillips driver with a JIS recess,
though apparently a JIS driver will turn a Phillips screw---people
claim better than a Phillips driver does.

That japanesescrews.com site claims it's offering JIS, shows a picture
of pozidriv, and then describes their product as Phillips.  Doesn't
exactly inspire confidence, as these are three different things.

On Wed, Sep 22, 2021 at 12:21 PM Ray West raywest@raywest.com wrote:

On 22/09/2021 16:50, Adrian Mariano wrote:

They seem to all work
together.  (Well, I can't speak personally about JIS, but certainly
for others, including square drive.)  I have gotten square drive stuff
from McFeelys, from McMaster, and even Home Depot, and it all works
together.

It's also possible to 'fit' some metric sized nuts to imperial threads,
use philips screw divers in pozidriv slots, and flatbladed screwdrivers
as chisels. It does not mean there are or not specifications/standards
for any or all of it.

http://www.japanesescrews.com/about-us.html  shows pozidriv heads, but
their pages only mention philips. It all fits where it touches.


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To unsubscribe send an email to discuss-leave@lists.openscad.org

I'm not sure what you're trying to say. I don't think that my square drive tooling is at all analogous to "fitting" metric and UTS threads to each other. I think the square drivers have been designed according to a consistent standard and they therefore all work interchangeably. It's not coincidence that all my drivers are within .001 inches of each other across several brands. I see no compelling reason to hypothesize that a bunch of tools that work fine together and are the same size are misfits, nor is there any "forcing" going on here. However, the recess size from the spec reference I found is smaller than all of my drivers, so if I had a screw with that recess none of my drivers would fit. My drivers fit great in my square drive screws. So something's not right with that spec data. I've never encountered a Pozi screw, but I've occasionally accidentally tried a Pozi bit in a Phillips recess and it does not fit. (I should throw away all the pozi bits.) Reportedly you'll also fail if you try to use a Phillips driver with a JIS recess, though apparently a JIS driver will turn a Phillips screw---people claim better than a Phillips driver does. That japanesescrews.com site claims it's offering JIS, shows a picture of pozidriv, and then describes their product as Phillips. Doesn't exactly inspire confidence, as these are three different things. On Wed, Sep 22, 2021 at 12:21 PM Ray West <raywest@raywest.com> wrote: > > > On 22/09/2021 16:50, Adrian Mariano wrote: > > They seem to all work > > together. (Well, I can't speak personally about JIS, but certainly > > for others, including square drive.) I have gotten square drive stuff > > from McFeelys, from McMaster, and even Home Depot, and it all works > > together. > > It's also possible to 'fit' some metric sized nuts to imperial threads, > use philips screw divers in pozidriv slots, and flatbladed screwdrivers > as chisels. It does not mean there are or not specifications/standards > for any or all of it. > > http://www.japanesescrews.com/about-us.html shows pozidriv heads, but > their pages only mention philips. It all fits where it touches. > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org
JB
Jordan Brown
Wed, Sep 22, 2021 5:20 PM

The best answer I found is
http://boltingspecialist.com/dimensions/asme-b18.6.3-type-3-square-recess-flat-countersunk-head-machine-screws/

I don't find anything that talks about the taper, other than to say
"slightly tapered".

The authoritative answer is somewhere in the vicinity of
https://webstore.ansi.org/Search/Find?in=1&st=ASME+B18.6
but it's hard to tell which, and the price tags are unreasonable.  (I
think their attitude is that for the people who really need it, dropping
~$100 for a standard is just part of the cost of doing business.)

The best answer I found is http://boltingspecialist.com/dimensions/asme-b18.6.3-type-3-square-recess-flat-countersunk-head-machine-screws/ I don't find anything that talks about the taper, other than to say "slightly tapered". The authoritative answer is somewhere in the vicinity of https://webstore.ansi.org/Search/Find?in=1&st=ASME+B18.6 but it's hard to tell which, and the price tags are unreasonable.  (I think their attitude is that for the people who really need it, dropping ~$100 for a standard is just part of the cost of doing business.)
L
larry
Wed, Sep 22, 2021 10:17 PM

On Wed, 2021-09-22 at 11:50 -0400, Adrian Mariano wrote:

I am aware that some people claim that square drive and Robertson are
different.  It's not clear that this is true.  The supposed
difference is whether the recess is tapered.  If you like wikipedia:
"A Robertson screw, also known as a square or Scrulox screw drive, is
specified as ANSI Type III Square Center".  Sounds like one animal.
Others have suggested that there are not two different standards but
just badly made square drive screws/drivers and well made ones, a
situation one might also encounter in the land of Phillips or slotted
screws.

I have had trouble with some screws and/or some bits. The main problem
is that of holding the screw or having it cam out. I have not figured
out if it was because of cheap bits or screws, or because of the
difference between square drive and Robertson.

I have heard that a Robertson will hold a Robertson screw well, but
that a square drive will not hold that same screw very well because of
the lack of proper taper.

Here's a link to some Robertson drive bits from Lee Valley Tools. Lee
Valley claims they are genuine Robertson bits. Might be worth picking
up a few and measuring. They can be purchased individually or in a set
of 12.

https://www.leevalley.com/en-us/shop/tools/hand-tools/screwdrivers/bits/57951-robertson-drive-bits?item=19J4031

I just checked my various Robertsons, and the following measurements
are taken with a low-cost digital caliper. The first and second
measurements are indicative of the taper, measurements in mm.

Yellow #0  2.04/1.75

Green  #1  2.54/2.33  2.48/2.33 *

Red    #2  3.08/2.89  3.21/2.71**

Black  #3  I Only have 1, but its whereabouts is a mystery

  • the first is a bit for a power driver, second is a screwdriver
    ** Appears to be a cheap screwdriver
On Wed, 2021-09-22 at 11:50 -0400, Adrian Mariano wrote: > I am aware that some people claim that square drive and Robertson are > different. It's not clear that this is true. The supposed > difference is whether the recess is tapered. If you like wikipedia: > "A Robertson screw, also known as a square or Scrulox screw drive, is > specified as ANSI Type III Square Center". Sounds like one animal. > Others have suggested that there are not two different standards but > just badly made square drive screws/drivers and well made ones, a > situation one might also encounter in the land of Phillips or slotted > screws. I have had trouble with some screws and/or some bits. The main problem is that of holding the screw or having it cam out. I have not figured out if it was because of cheap bits or screws, or because of the difference between square drive and Robertson. I have heard that a Robertson will hold a Robertson screw well, but that a square drive will not hold that same screw very well because of the lack of proper taper. Here's a link to some Robertson drive bits from Lee Valley Tools. Lee Valley claims they are genuine Robertson bits. Might be worth picking up a few and measuring. They can be purchased individually or in a set of 12. https://www.leevalley.com/en-us/shop/tools/hand-tools/screwdrivers/bits/57951-robertson-drive-bits?item=19J4031 I just checked my various Robertsons, and the following measurements are taken with a low-cost digital caliper. The first and second measurements are indicative of the taper, measurements in mm. Yellow #0 2.04/1.75 Green #1 2.54/2.33 2.48/2.33 * Red #2 3.08/2.89 3.21/2.71** Black #3 I Only have 1, but its whereabouts is a mystery * the first is a bit for a power driver, second is a screwdriver ** Appears to be a cheap screwdriver
JW
Jan Wieck
Thu, Sep 23, 2021 1:34 PM

On 9/22/21 12:21 PM, Ray West wrote:

It's also possible to 'fit' some metric sized nuts to imperial threads,
use philips screw divers in pozidriv slots, and flatbladed screwdrivers
as chisels. It does not mean there are or not specifications/standards
for any or all of it.

And if it doesn't fit, don't try to force it. Just use a bigger hammer.

--
Jan Wieck

On 9/22/21 12:21 PM, Ray West wrote: > It's also possible to 'fit' some metric sized nuts to imperial threads, > use philips screw divers in pozidriv slots, and flatbladed screwdrivers > as chisels. It does not mean there are or not specifications/standards > for any or all of it. And if it doesn't fit, don't try to force it. Just use a bigger hammer. -- Jan Wieck