### Distance Between Teeth On A Rack in BOSL2/gears.scad

NS
Nathan Sokalski
Sun, May 5, 2024 7:46 PM

I'm very new to working with gears in OpenSCAD (actually, gears in general), and am trying to learn the BOSL2 gears.scad library (https://github.com/BelfrySCAD/BOSL2/blob/master/gears.scad)
github.com
I am currently looking at the rack() module, and am trying to figure out the distance between the teeth in the generated rack. There are many functions, and with my limited knowledge and unfamiliarity of some of the terminology, I am having trouble finding the function that does this. Can somebody help me figure out which function (or how to calculate) the distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.commailto:njsokalski@hotmail.com

AM
Sun, May 5, 2024 8:47 PM

You might have better luck making sense of everything if you start with
circular gears (the normal case) instead of racks, where the terminology
may make less sense.  Did you read the section at the top about the way
involute gears work and the associated terminology?

You can specify circ_pitch=x to make the teeth x units wide.  Or you can
use the circular_pitch() function to compute it from the module or
diametral pitch.  Why do you need to know this number?  Is it to determine

On Sun, May 5, 2024 at 3:47 PM Nathan Sokalski via Discuss <

I'm very new to working with gears in OpenSCAD (actually, gears in
general), and am trying to learn the BOSL2 gears.scad library (
and manipulators to make working with OpenSCAD easier. BETA -
github.com
I am currently looking at the rack() module, and am trying to figure out
the distance between the teeth in the generated rack. There are many
functions, and with my limited knowledge and unfamiliarity of some of the
terminology, I am having trouble finding the function that does this. Can
somebody help me figure out which function (or how to calculate) the
distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.com

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

NS
Nathan Sokalski
Sun, May 5, 2024 10:19 PM

The reason I want to know this is because I want to position the rack to be aligned with the other gears. It would also be good to know the length of the rack. Something that would be really nice would be a diagram for each gear type containing the different parts and (if applicable) what function can be used to calculate them. I will try to at the involute gears section again to see if it helps me make more sense. I think one of the things confusing me is when the same terminology and/or variable/parameter names are used for round & flat gears. Thanks for your help, hopefully I can get some of it figured out.

Nathan Sokalski
njsokalski@hotmail.commailto:njsokalski@hotmail.com

Sent: Sunday, May 5, 2024 4:47 PM

You might have better luck making sense of everything if you start with circular gears (the normal case) instead of racks, where the terminology may make less sense.  Did you read the section at the top about the way involute gears work and the associated terminology?

You can specify circ_pitch=x to make the teeth x units wide.  Or you can use the circular_pitch() function to compute it from the module or diametral pitch.  Why do you need to know this number?  Is it to determine the length of your rack?

On Sun, May 5, 2024 at 3:47 PM Nathan Sokalski via Discuss <discuss@lists.openscad.orgmailto:discuss@lists.openscad.org> wrote:
I'm very new to working with gears in OpenSCAD (actually, gears in general), and am trying to learn the BOSL2 gears.scad library (https://github.com/BelfrySCAD/BOSL2/blob/master/gears.scad)
github.comhttp://github.com
I am currently looking at the rack() module, and am trying to figure out the distance between the teeth in the generated rack. There are many functions, and with my limited knowledge and unfamiliarity of some of the terminology, I am having trouble finding the function that does this. Can somebody help me figure out which function (or how to calculate) the distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.commailto:njsokalski@hotmail.com

AM
Sun, May 5, 2024 11:58 PM

Well, maybe this is what was called "quirky" above, but if gear terminology
didn't use the same labels for racks as for round gears you'd be hopelessly
confused if you wanted  your rack to actually mate with a round gear.  The
teeth need to be the same form for the gears to mate, so the description
should be the same!  I don't know what the "different parts" of the gears
are that would appear on the proposed diagram.  There's one diagram that
shows different circles.  Perhaps circular pitch could be added, but that
seems like it covers things.  Since all gears work on the same system, the
pictures of different gears would basically be the same.  Maybe it helps a
bit if you think of a rack as a circular gear with infinite diameter.  :)
Ideally you shouldn't need to compute gear minutiae but rather should be
able to use more automated schemes to position things the way you need, but
gears are complex enough that making everything automated is impossible due
to things like profile shifting and tip shortening that depends on what the
mating gears are.

Revar is hoping to write gear attachment code that will automatically
position gears relative to other gears with the teeth properly meshing.
But that's a thing for the future.  It would definitely be nice to have, as
positioning gears can be a pain.

On Sun, May 5, 2024 at 6:19 PM Nathan Sokalski via Discuss <

The reason I want to know this is because I want to position the rack to
be aligned with the other gears. It would also be good to know the length
of the rack. Something that would be really nice would be a diagram for
each gear type containing the different parts and (if applicable) what
function can be used to calculate them. I will try to at the involute gears
section again to see if it helps me make more sense. I think one of the
things confusing me is when the same terminology and/or variable/parameter
names are used for round & flat gears. Thanks for your help, hopefully I
can get some of it figured out.

## Nathan Sokalski njsokalski@hotmail.com

Sent: Sunday, May 5, 2024 4:47 PM

Subject: [OpenSCAD] Re: Distance Between Teeth On A Rack in

You might have better luck making sense of everything if you start with
circular gears (the normal case) instead of racks, where the terminology
may make less sense.  Did you read the section at the top about the way
involute gears work and the associated terminology?

You can specify circ_pitch=x to make the teeth x units wide.  Or you can
use the circular_pitch() function to compute it from the module or
diametral pitch.  Why do you need to know this number?  Is it to determine

On Sun, May 5, 2024 at 3:47 PM Nathan Sokalski via Discuss <

I'm very new to working with gears in OpenSCAD (actually, gears in
general), and am trying to learn the BOSL2 gears.scad library (
and manipulators to make working with OpenSCAD easier. BETA -
github.com
I am currently looking at the rack() module, and am trying to figure out
the distance between the teeth in the generated rack. There are many
functions, and with my limited knowledge and unfamiliarity of some of the
terminology, I am having trouble finding the function that does this. Can
somebody help me figure out which function (or how to calculate) the
distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.com

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

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

NH
Mon, May 6, 2024 12:08 AM

NopSCADlib has gears and racks and an example of how to mesh them, which
will animate if opened in the GUI.

[image: image.png]
On Mon, 6 May 2024 at 00:59, Adrian Mariano via Discuss <

Well, maybe this is what was called "quirky" above, but if gear
terminology didn't use the same labels for racks as for round gears you'd
be hopelessly confused if you wanted  your rack to actually mate with a
round gear.  The teeth need to be the same form for the gears to mate, so
the description should be the same!  I don't know what the "different
parts" of the gears are that would appear on the proposed diagram.
There's one diagram that shows different circles.  Perhaps circular pitch
could be added, but that seems like it covers things.  Since all gears work
on the same system, the pictures of different gears would basically be the
same.  Maybe it helps a bit if you think of a rack as a circular gear with
infinite diameter.  :)  Ideally you shouldn't need to compute gear minutiae
but rather should be able to use more automated schemes to position things
the way you need, but gears are complex enough that making everything
automated is impossible due to things like profile shifting and tip
shortening that depends on what the mating gears are.

Revar is hoping to write gear attachment code that will automatically
position gears relative to other gears with the teeth properly meshing.
But that's a thing for the future.  It would definitely be nice to have, as
positioning gears can be a pain.

On Sun, May 5, 2024 at 6:19 PM Nathan Sokalski via Discuss <

The reason I want to know this is because I want to position the rack to
be aligned with the other gears. It would also be good to know the length
of the rack. Something that would be really nice would be a diagram for
each gear type containing the different parts and (if applicable) what
function can be used to calculate them. I will try to at the involute gears
section again to see if it helps me make more sense. I think one of the
things confusing me is when the same terminology and/or variable/parameter
names are used for round & flat gears. Thanks for your help, hopefully I
can get some of it figured out.

## Nathan Sokalski njsokalski@hotmail.com

Sent: Sunday, May 5, 2024 4:47 PM
To: OpenSCAD general discussion Mailing-list <
Subject: [OpenSCAD] Re: Distance Between Teeth On A Rack in

You might have better luck making sense of everything if you start with
circular gears (the normal case) instead of racks, where the terminology
may make less sense.  Did you read the section at the top about the way
involute gears work and the associated terminology?

You can specify circ_pitch=x to make the teeth x units wide.  Or you can
use the circular_pitch() function to compute it from the module or
diametral pitch.  Why do you need to know this number?  Is it to determine

On Sun, May 5, 2024 at 3:47 PM Nathan Sokalski via Discuss <

I'm very new to working with gears in OpenSCAD (actually, gears in
general), and am trying to learn the BOSL2 gears.scad library (
and manipulators to make working with OpenSCAD easier. BETA -
github.com
I am currently looking at the rack() module, and am trying to figure out
the distance between the teeth in the generated rack. There are many
functions, and with my limited knowledge and unfamiliarity of some of the
terminology, I am having trouble finding the function that does this. Can
somebody help me figure out which function (or how to calculate) the
distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.com

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

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

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

RD
Revar Desmera
Mon, May 6, 2024 1:01 AM

Simplest answer, if you make a rack with `rack(pitch=5, ...)` then there will be 5 OpenSCAD units of distance between the centers of consecutive teeth.

• Revar

On May 5, 2024, at 3:19 PM, Nathan Sokalski via Discuss discuss@lists.openscad.org wrote:

The reason I want to know this is because I want to position the rack to be aligned with the other gears. It would also be good to know the length of the rack. Something that would be really nice would be a diagram for each gear type containing the different parts and (if applicable) what function can be used to calculate them. I will try to at the involute gears section again to see if it helps me make more sense. I think one of the things confusing me is when the same terminology and/or variable/parameter names are used for round & flat gears. Thanks for your help, hopefully I can get some of it figured out.

Nathan Sokalski
njsokalski@hotmail.com mailto:njsokalski@hotmail.com
Sent: Sunday, May 5, 2024 4:47 PM

You might have better luck making sense of everything if you start with circular gears (the normal case) instead of racks, where the terminology may make less sense.  Did you read the section at the top about the way involute gears work and the associated terminology?

You can specify circ_pitch=x to make the teeth x units wide.  Or you can use the circular_pitch() function to compute it from the module or diametral pitch.  Why do you need to know this number?  Is it to determine the length of your rack?

On Sun, May 5, 2024 at 3:47 PM Nathan Sokalski via Discuss <discuss@lists.openscad.org mailto:discuss@lists.openscad.org> wrote:
I'm very new to working with gears in OpenSCAD (actually, gears in general), and am trying to learn the BOSL2 gears.scad library (https://github.com/BelfrySCAD/BOSL2/blob/master/gears.scad)
github.com http://github.com/
I am currently looking at the rack() module, and am trying to figure out the distance between the teeth in the generated rack. There are many functions, and with my limited knowledge and unfamiliarity of some of the terminology, I am having trouble finding the function that does this. Can somebody help me figure out which function (or how to calculate) the distance between the teeth of a rack gear? Thanks!

Nathan Sokalski
njsokalski@hotmail.com mailto:njsokalski@hotmail.com