I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l...s/StarWars.jpg
http://i290.photobucket.com/albums/l...arWarsYoke.jpg
http://i290.photobucket.com/albums/l...rWarsYoke2.jpg
http://i290.photobucket.com/albums/l...arsYokeKit.jpg

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.
get a cheap book, "Gears and gear cutting" by Ivan Law.

Delrin sounds like a good choice here. or maybe move up to brass which
is veryeasy to machine for this project.

On Nov 16, 1:31*am, Searcher7 wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Darren Harris
Staten Island, New York.

I would not look for the absolute best material for wear resistance.
Anything that is real wear resistant will be a pain to machine.
Better to make ten sets of gears out of something that is easy to
machine than one set out of a material that has to be ground because
it is very hard.


Dan

On 11/16/2012 4:23 AM, Karl Townsend wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.
get a cheap book, "Gears and gear cutting" by Ivan Law.

Delrin sounds like a good choice here. or maybe move up to brass which
is veryeasy to machine for this project.


the headlights of my corvette have a plastic (delrin?) gear that is
known for turning to dust in about 10 years or so. the replacement ones
available are brass. i'd agree with karl about this.

On Nov 16, 12:41*pm, chaniarts wrote:
On 11/16/2012 4:23 AM, Karl Townsend wrote:



So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.
get a cheap book, "Gears and gear cutting" by Ivan Law.

Delrin sounds like a good choice here. or maybe move up to brass which
is veryeasy to machine for this project.

the headlights of my corvette have a plastic (delrin?) gear that is
known for turning to dust in about 10 years or so. the replacement ones
available are brass. i'd agree with karl about this.

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

I do already have the book "Gears and gear cutting" by Ivan Law.

Thanks a lot.

Darren Harris
Staten Island, New York.

On Fri, 16 Nov 2012 04:43:02 -0800 (PST), "
wrote:

On Nov 16, 1:31*am, Searcher7 wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Darren Harris
Staten Island, New York.

I would not look for the absolute best material for wear resistance.
Anything that is real wear resistant will be a pain to machine.
Better to make ten sets of gears out of something that is easy to
machine than one set out of a material that has to be ground because
it is very hard.


Dan

One does need to consider the use though. I once made a new drive gear
for a butcher's meat slicer. The original had been made from plastic
and had stripped the teeth so I made the new one of brass. When we
assembled the damned thing and tested it sounded like a very large
siren Rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr.

It seems that there is more then one reason for selecting gear
materials :-)
--
Cheers,
John B.

On Nov 16, 8:16*pm, John B. wrote:
On Fri, 16 Nov 2012 04:43:02 -0800 (PST), "









wrote:
On Nov 16, 1:31*am, Searcher7 wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Darren Harris
Staten Island, New York.

I would not look for the absolute best material for wear resistance.
Anything that is real wear resistant will be a pain to machine.
Better to make ten sets of gears out of something that is easy to
machine than one set out of a material that has to be ground because
it is very hard.

Dan

One does need to consider the use though. I once made a new drive gear
for a butcher's meat slicer. The original had been made from plastic
and had stripped the teeth so I made the new one of brass. When we
assembled the damned thing and tested it sounded like a very large
siren Rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr.

It seems that there is more then one reason for selecting gear
materials :-)
--
Cheers,
John B.

Yes, I thought about that. I was wondering how loud can brass gears
from just turning a yoke between left and right like a steering wheel.
Would you be able to hear them at all? (I know you cannot hear the
original plastic gears).

Thanks.

Darren Harris
Staten Island, New York.

On 2012-11-16, Searcher7 wrote:
I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l...s/StarWars.jpg
http://i290.photobucket.com/albums/l...arWarsYoke.jpg
http://i290.photobucket.com/albums/l...rWarsYoke2.jpg
http://i290.photobucket.com/albums/l...arsYokeKit.jpg

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

The kit looks to be Delrin, and that is a good choice as plastic
gears not having to transmit too much torque go. And given that they
are driving pots -- look like the old Allen Bradley ones -- you should
not have that much torque, unless the system is missing rotational
stops, so it works against the stops in the pots.

If you want them to be metal instead, you really want two
different metals -- and especially not aluminum meshing with aluminum.
(But aluminum would be easy to machine.) Make the larger ones of
aluminum, and the smaller ones of brass and you should be fine. A
different grease would likely be called for to lubricate the mesh of the
gears. You could make the smaller gears of bronze instead, but harder
to machine and more expensive material. I doubt that you will wear a
brass/aluminum mesh out in your lifetime just turning pots.

You will need an index head to position it for the cuts, and you
will need to know the pitch, and the pressure angle (likely 20 degrees
or 14-1/2 degrees, unless it is metric (module) gears.)

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2012-11-16, Searcher7 wrote:
On Nov 16, 12:41*pm, chaniarts wrote:
On 11/16/2012 4:23 AM, Karl Townsend wrote:



So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

[ ... ]

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

Do you have a milling machine as well? And an index head?
Otherwise, how do you plan to cut the teeth? I feel it unlikely for you
to have a hobbing machine -- those are typically large, heavy, and rare.

I do already have the book "Gears and gear cutting" by Ivan Law.

A good start.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

I'd stick to insulative material. Delrin is machinable plastic.

Conductive paths can cause unwanted connections.

Martin

On 11/16/2012 12:31 AM, Searcher7 wrote:
I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l...s/StarWars.jpg
http://i290.photobucket.com/albums/l...arWarsYoke.jpg
http://i290.photobucket.com/albums/l...rWarsYoke2.jpg
http://i290.photobucket.com/albums/l...arsYokeKit.jpg

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.

"Searcher7" wrote in message
...
I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l...s/StarWars.jpg
http://i290.photobucket.com/albums/l...arWarsYoke.jpg
http://i290.photobucket.com/albums/l...rWarsYoke2.jpg
http://i290.photobucket.com/albums/l...arsYokeKit.jpg

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.

This was actually one of my favorite games back when. It had a special
display with vector graphics, like Asteroids, but in color.

Try looking for appropriate replacement gears from some of the online
catalogs like he
https://sdp-si.com/eStore/

On Nov 16, 10:43*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:









I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

* * * * The kit looks to be Delrin, and that is a good choice as plastic
gears not having to transmit too much torque go. *And given that they
are driving pots -- look like the old Allen Bradley ones -- you should
not have that much torque, unless the system is missing rotational
stops, so it works against the stops in the pots.

* * * * If you want them to be metal instead, you really want two
different metals -- and especially not aluminum meshing with aluminum.
(But aluminum would be easy to machine.) *Make the larger ones of
aluminum, and the smaller ones of brass and you should be fine. *A
different grease would likely be called for to lubricate the mesh of the
gears. *You could make the smaller gears of bronze instead, but harder
to machine and more expensive material. *I doubt that you will wear a
brass/aluminum mesh out in your lifetime just turning *pots.

* * * * You will need an index head to position it for the cuts, and you
will need to know the pitch, and the pressure angle (likely 20 degrees
or 14-1/2 degrees, unless it is metric (module) gears.)

* * * * Good Luck,
* * * * * * * * DoN.

--
* * * * * * * * * Remove oil spill source from e-mail
*Email: * | Voice (all times): (703) 938-4564
* * * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---

Yes unlike the original gears the gears in the kit are made of Delrin.
I know Bronze is more expensive and more difficult to machine, but are
there any advantages of using it over Brass?

I'll first have to learn how to measure the gears. The larger 60 tooth
gear has no writing on it, bu the 28 tooth gear says 24P, 28T, and
"Stock Gear".(I assume that means it is an easily obtainable
standard). The writing on the 14 tooth gear is too small to read.

Thanks.

Darren Harris
Staten Island, New York.

On Nov 16, 10:50*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:

On Nov 16, 12:41 pm, chaniarts wrote:
On 11/16/2012 4:23 AM, Karl Townsend wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

* * * * [ ... ]

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

* * * * Do you have a milling machine as well? *And an index head?
Otherwise, how do you plan to cut the teeth? *I feel it unlikely for you
to have a hobbing machine -- those are typically large, heavy, and rare.

I do already have the book "Gears and gear cutting" by Ivan Law.

* * * * A good start.

* * * * Good Luck,
* * * * * * * * DoN.

--
* * * * * * * * * Remove oil spill source from e-mail
*Email: * | Voice (all times): (703) 938-4564
* * * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

Darren Harris
Staten Island, New York

That's not a problem. Anything that needs to be conductive is secured
out of the way for obvious reasons.

Darren Harris
Staten Island, New York.

On Nov 16, 10:53*pm, Martin Eastburn
wrote:
I'd stick to insulative material. *Delrin is machinable plastic.

Conductive paths can cause unwanted connections.

Martin

On 11/16/2012 12:31 AM, Searcher7 wrote:







I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.

On Nov 16, 11:34*pm, "anorton"
wrote:
"Searcher7" wrote in message

...









I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

I have a Star Wars game that uses a yoke controller that has gears
inside the housing:

http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...

I'd like to reproduce the spur gears inside the yoke, but make them
better if that is possible.

They are about 11/16", 1-1/4" and 2-9/16" respectively.

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

Thanks.

Darren Harris
Staten Island, New York.

This was actually one of my favorite games back when. *It had a special
display with vector graphics, like Asteroids, but in color.

Try looking for appropriate replacement gears from some of the online
catalogs like hehttps://sdp-si.com/eStore/

Well that would defeat the purpose of me learning how to do this.

Also, In addition to Star Wars, I have two other vector games as well.
Asteroids and Star Trek. (All my other ones are raster games).

Darren Harris
Staten Island, New York.

On Fri, 16 Nov 2012 22:41:39 -0800 (PST), Searcher7
wrote:

On Nov 16, 10:50*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:

On Nov 16, 12:41 pm, chaniarts wrote:
On 11/16/2012 4:23 AM, Karl Townsend wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

* * * * [ ... ]

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

* * * * Do you have a milling machine as well? *And an index head?
Otherwise, how do you plan to cut the teeth? *I feel it unlikely for you
to have a hobbing machine -- those are typically large, heavy, and rare.

I do already have the book "Gears and gear cutting" by Ivan Law.

* * * * A good start.

* * * * Good Luck,
* * * * * * * * DoN.

--
* * * * * * * * * Remove oil spill source from e-mail
*Email: * | Voice (all times): (703) 938-4564
* * * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

Darren Harris
Staten Island, New York

Can you machine a 28 tooth gear with that thing. 360/28=12.857
degrees?
--
Cheers,
John B.

"John B." wrote in message
...
On Fri, 16 Nov 2012 04:43:02 -0800 (PST), "
wrote:

On Nov 16, 1:31 am, Searcher7 wrote:

It seems that there is more then one reason for selecting gear
materials :-)
--
Cheers,
John B.

A big reason is the rigidity and power of your machine tools. The gear
cutter has to cut the entire periphery of the tooth space at once,
which puts a heavy load on the cutter and the indexer supporting the
blank.

jsw

"BQ340" wrote in message
. com...

I had to cut a one-off steering gear for my tractor when the
original was no longer available.

I made a really simple fixture, it was basically an angle plate that
the gear blank mounted to and a dowel pin. I cut a tooth,
repositioned the blank so the dowel pin was locating the tooth, and
repeated.

MikeB

That's a very good idea for a sector gear but not for a full one, as
the spacing error accumulates and the tooth width between the first
and last cuts is unlikely to be acceptable.

Long ago master index plates were generated a similar way, by stepping
around the circle with dividers and attempting to adjust out the
closure error.

Cutting a steering sector:
https://picasaweb.google.com/KB1DAL/...10360947850418
https://picasaweb.google.com/KB1DAL/...10370886636434
https://picasaweb.google.com/KB1DAL/...21964003279458

jsw

On 11/16/2012 08:33 PM, anorton wrote:

This was actually one of my favorite games back when. It had a special
display with vector graphics, like Asteroids, but in color.

I remember the sit-down SW game at the local billard hall in the
late-seventies. Seemed fascinating, but I was more into pinball at the
time.

Jon

On Fri, 16 Nov 2012 22:41:39 -0800 (PST), Searcher7
wrote:

On Nov 16, 10:50*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:

On Nov 16, 12:41 pm, chaniarts wrote:
On 11/16/2012 4:23 AM, Karl Townsend wrote:

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

* * * * [ ... ]

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

* * * * Do you have a milling machine as well? *And an index head?
Otherwise, how do you plan to cut the teeth? *I feel it unlikely for you
to have a hobbing machine -- those are typically large, heavy, and rare.

I do already have the book "Gears and gear cutting" by Ivan Law.

* * * * A good start.

* * * * Good Luck,
* * * * * * * * DoN.

--
* * * * * * * * * Remove oil spill source from e-mail
*Email: * | Voice (all times): (703) 938-4564
* * * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

Darren Harris
Staten Island, New York
Brass or bronze running against Delrin or aluminum will work fine.
Common bearing bronze is not much harder to machine than brass so use
what you want. Since you have Ivan Law's book you know how to grind a
fly cutter to the proper shape. Does your rotary table have index
plates? If not then maybe you should make at least one for cutting the
gears.
Eric

On 2012-11-17, Searcher7 wrote:
On Nov 16, 10:43*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:

I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

[ ... ]

They are about 11/16", 1-1/4" and 2-9/16" respectively.

Better precision measuring the diameter is called for.
Certainly 1/16" steps are not small enough. Don't you have a digital
caliper capable of at least 6" measurements? (Or even a dial one or a
vernier one). Measure to 0.001", not to 1/16".

So I'm curious as to what would be the absolute best material to make
these gears out of if the goal was that they last as long as possible,
as well as any tips in making them. (The original ones were some sort
of plastic and someone did make reproductions out of Delrin).

* * * * The kit looks to be Delrin, and that is a good choice as plastic
gears not having to transmit too much torque go. *And given that they
are driving pots -- look like the old Allen Bradley ones -- you should
not have that much torque, unless the system is missing rotational
stops, so it works against the stops in the pots.

* * * * If you want them to be metal instead, you really want two
different metals -- and especially not aluminum meshing with aluminum.
(But aluminum would be easy to machine.) *Make the larger ones of
aluminum, and the smaller ones of brass and you should be fine. *A
different grease would likely be called for to lubricate the mesh of the
gears. *You could make the smaller gears of bronze instead, but harder
to machine and more expensive material. *I doubt that you will wear a
brass/aluminum mesh out in your lifetime just turning *pots.

* * * * You will need an index head to position it for the cuts, and you
will need to know the pitch, and the pressure angle (likely 20 degrees
or 14-1/2 degrees, unless it is metric (module) gears.)

[ ... ]

Yes unlike the original gears the gears in the kit are made of Delrin.
I know Bronze is more expensive and more difficult to machine, but are
there any advantages of using it over Brass?

I'll first have to learn how to measure the gears. The larger 60 tooth
gear has no writing on it, bu the 28 tooth gear says 24P, 28T, and
"Stock Gear".(I assume that means it is an easily obtainable
standard). The writing on the 14 tooth gear is too small to read.

"Stock Gear" is a manufacturer of standard gears. It is likely
made by moulding, not cutting. But it is also likely bored out by the
person/company who sold it to you, and a new hub pressed in to fit the
rest of the stuff.

So -- it is 24 DP (Diametrical Pitch) and has 28 teeth (count
the teeth to verify this),. I don't know what the pressure angle is.
The photo is not directly on axis, is it is difficult to count the teeth
from the photo (the side ones sort of merge together), so *you* count
them to verify this. The other gears will have the same diametrical
pitch (and pressure angle) an you simply need to count the teeth on each
to know its size. I come somewhat close to 16 teeth on the smallest
gear (not certain because of the fuzz of the lossy JPEG compression, but
that makes 24 teeth seem reasonable for the larger of the two smaller
gears.

The easiest way to determine whether it is 20 degree PA or
14-1/2 degree PA is with a gear tooth gauge. The gauge is likely 20 PA,
so it if is a clean fit to the gear, it is the same. If there is a lot
of light in the mesh, it is likely 14-1/2 degree PA.

Let's see -- the formula for outside diameter of a gear is:

N = tooth count
P = diametrical pitch

(N + 2) / P

So the precise OD of the 28-tooth one should be 1.2500" (which
matches your 1-1/4")

The 16-tooth one: 0.750" (3/4" not your 11/16" -- if it is truly
16 teeth.

The 60-tooth ones: 2.5833" (2" and 9.3333/16", not 9/16")

So -- you see how the precision of measurement is important.
Throw away that inch scale (or hide it) and use the calipers. Forget
about "about" for measurements of anything you make by machining.

The formulas for the gear measurements are in the book you say
you have -- or in _Machinery's Handbook_ (where I go). In the 29th
edition, the formula which I used are on page 2132, with others on the
previous page.

Page 2129 has drawings of three different pressure angles (10
degrees, 20 degrees, and 30 degrees, to show you how the shape of the
teeth change.

The pitch diameter of each is simply the tooth count divided by
the DP, so you get (from smallest to largest) 0.6667", 1.1667", and
2.500") This is the diameter about half way from the crest of the tooth
to the root -- and is best measured with a three-wire technique. It is
mostly good for determining the spacing of the centers of two gears, 1/2
the pitch diameter of one added to 1/2 the pitch diameter of the other.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2012-11-17, Searcher7 wrote:
On Nov 16, 10:50*pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:

[ ... ]

Ok, so making the gears out of brass is a *step-up* from Delrin. (I'm
assuming that that's the best I can do on a mini-lathe).

* * * * Do you have a milling machine as well? *And an index head?
Otherwise, how do you plan to cut the teeth? *I feel it unlikely for you
to have a hobbing machine -- those are typically large, heavy, and rare.

I do already have the book "Gears and gear cutting" by Ivan Law.

[ ... ]

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

O.K. Does the rotary table have a hole plate and arm with
sector arms? If not, it will be tricky for some of the gears. 60 tooh
is no problem. 16 tooth (if I am right about that gear), also no
problem. But the 26 tooth (or was it 28?) will be tricky. For each cut
you need to advance it:

26 13.8462 degrees (13 degrees 50 minutes 46 seconds)
28 12.8571 degrees (12 degrees 51 minutes 26 seconds)

With the right hole plate, and the arm and sector arms, it is
easy to set it up to avoid problems. And that is what an index head
has.

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. (Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. Still a
little tricky to calculate the position of the pin for each one.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Thu, 15 Nov 2012 22:31:57 -0800 (PST)
Searcher7 wrote:

I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.
big snip

You may find this website of particular interest, provided you haven't
already found it

http://www.deansphotographica.com/ma.../projects.html

especially:

http://www.deansphotographica.com/ma...arcutting.html

http://www.deansphotographica.com/ma...ultipoint.html

You inspired me to go find these web pages again. I lost them awhile
back with a computer crash...


--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

On Nov 17, 3:45 pm, "DoN. Nichols" wrote:
On 2012-11-17, Searcher7 wrote:

On Nov 16, 10:43 pm, "DoN. Nichols" wrote:
On 2012-11-16, Searcher7 wrote:
I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

[ ... ]

They are about 11/16", 1-1/4" and 2-9/16" respectively.

Better precision measuring the diameter is called for.
Certainly 1/16" steps are not small enough. Don't you have a digital
caliper capable of at least 6" measurements? (Or even a dial one or a
vernier one). Measure to 0.001", not to 1/16".


Oops! I forgot not to give approximate numbers. :-)
60 tooth = 2.575"
28 tooth = 1.245"
14 tooth = 0.655

I'll first have to learn how to measure the gears. The larger 60 tooth
gear has no writing on it, bu the 28 tooth gear says 24P, 28T, and
"Stock Gear".(I assume that means it is an easily obtainable
standard). The writing on the 14 tooth gear is too small to read.

"Stock Gear" is a manufacturer of standard gears. It is likely
made by moulding, not cutting. But it is also likely bored out by the
person/company who sold it to you, and a new hub pressed in to fit the
rest of the stuff.

These reproduction gears I measured are made of Delrin. But I can't
attest to the degree of quality control. So I'd just as well start
from scratch as long as the number of teeth are correct for each gear.

So -- it is 24 DP (Diametrical Pitch) and has 28 teeth (count
the teeth to verify this),. I don't know what the pressure angle is.
The photo is not directly on axis, is it is difficult to count the teeth
from the photo (the side ones sort of merge together), so *you* count
them to verify this. The other gears will have the same diametrical
pitch (and pressure angle) an you simply need to count the teeth on each
to know its size. I come somewhat close to 16 teeth on the smallest
gear (not certain because of the fuzz of the lossy JPEG compression, but
that makes 24 teeth seem reasonable for the larger of the two smaller
gears.

The easiest way to determine whether it is 20 degree PA or
14-1/2 degree PA is with a gear tooth gauge. The gauge is likely 20 PA,
so it if is a clean fit to the gear, it is the same. If there is a lot
of light in the mesh, it is likely 14-1/2 degree PA.

Let's see -- the formula for outside diameter of a gear is:

N = tooth count
P = diametrical pitch

(N + 2) / P

So the precise OD of the 28-tooth one should be 1.2500" (which
matches your 1-1/4")

The 16-tooth one: 0.750" (3/4" not your 11/16" -- if it is truly
16 teeth.

The 60-tooth ones: 2.5833" (2" and 9.3333/16", not 9/16")

So -- you see how the precision of measurement is important.
Throw away that inch scale (or hide it) and use the calipers. Forget
about "about" for measurements of anything you make by machining.

The formulas for the gear measurements are in the book you say
you have -- or in _Machinery's Handbook_ (where I go). In the 29th
edition, the formula which I used are on page 2132, with others on the
previous page.

Page 2129 has drawings of three different pressure angles (10
degrees, 20 degrees, and 30 degrees, to show you how the shape of the
teeth change.

The pitch diameter of each is simply the tooth count divided by
the DP, so you get (from smallest to largest) 0.6667", 1.1667", and
2.500") This is the diameter about half way from the crest of the tooth
to the root -- and is best measured with a three-wire technique. It is
mostly good for determining the spacing of the centers of two gears, 1/2
the pitch diameter of one added to 1/2 the pitch diameter of the other.

Thanks. Here are some pics of the 60 tooth gear:

http://i290.photobucket.com/albums/l...jects/60Tb.jpg
http://i290.photobucket.com/albums/l...jects/60Ta.jpg
http://i290.photobucket.com/albums/l...jects/60Tc.jpg

On Nov 17, 3:56*pm, "DoN. Nichols" wrote:
On 2012-11-17, Searcher7 wrote:

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

* * * * O.K. *Does the rotary table have a hole plate and arm with
sector arms? *If not, it will be tricky for some of the gears. *60 tooh
is no problem. *16 tooth (if I am right about that gear), also no
problem. *But the 26 tooth (or was it 28?) will be tricky. *For each cut
you need to advance it:

26 * * *13.8462 degrees (13 degrees 50 minutes 46 seconds)
28 * * *12.8571 degrees (12 degrees 51 minutes 26 seconds)

* * * * With the right hole plate, and the arm and sector arms, it is
easy to set it up to avoid problems. *And that is what an index head
has.

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

* * * * The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. *And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. *(Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. *Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

Thanks a lot.

Darren Harris
Staten Island, New York.

* * * * The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. *And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. *(Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. *Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

Thanks a lot.

Darren Harris
Staten Island, New York.
That little table will be perfect with the dividing plates to make
your little gears. Please post photos of your finished work.
Eric

On Nov 18, 3:12*pm, Leon Fisk wrote:
On Thu, 15 Nov 2012 22:31:57 -0800 (PST)

Searcher7 wrote:
I want to undertake a gear making project for practice if not nothing
else. I figure I'll try something I'll likely need in the future.

big snip

You may find this website of particular interest, provided you haven't
already found it

http://www.deansphotographica.com/ma.../projects.html

especially:

http://www.deansphotographica.com/ma...arcutting/gear...

http://www.deansphotographica.com/ma...ltipoint/multi...

You inspired me to go find these web pages again. I lost them awhile
back with a computer crash...

--
Leon Fisk
Grand Rapids *MI/Zone 5b
Remove no.spam for email

Thanks for the links. :-)

Darren Harris
Staten Island, New York.

On 2012-11-19, Searcher7 wrote:
On Nov 17, 3:45 pm, "DoN. Nichols" wrote:

[ ... ]

Oops! I forgot not to give approximate numbers. :-)
60 tooth = 2.575"
28 tooth = 1.245"
14 tooth = 0.655

Not 16-tooth, O.K.

O.K. A little different from my calculations. It sounds as
though the crest of the teeth has been shaved a little, No problem as
long as the pitch diameter is correct.

So the precise OD of the 28-tooth one should be 1.2500" (which
matches your 1-1/4")

The 16-tooth one: 0.750" (3/4" not your 11/16" -- if it is truly
16 teeth.

The 60-tooth ones: 2.5833" (2" and 9.3333/16", not 9/16")

[ ... ]

Thanks. Here are some pics of the 60 tooth gear:

http://i290.photobucket.com/albums/l...jects/60Tb.jpg
http://i290.photobucket.com/albums/l...jects/60Ta.jpg
http://i290.photobucket.com/albums/l...jects/60Tc.jpg

O.K. But we knew the count of teeth there. It was the smaller
ones which I was wondering about -- and you have now told met hat the
smallest one was 14 teeth, not 16, so my calculation for size was wrong.

On Nov 17, 3:56*pm, "DoN. Nichols" wrote:
On 2012-11-17, Searcher7 wrote:

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

* * * * O.K. *Does the rotary table have a hole plate and arm with
sector arms? *If not, it will be tricky for some of the gears. *60 tooh
is no problem. *16 tooth (if I am right about that gear), also no
problem. *But the 26 tooth (or was it 28?) will be tricky. *For each cut
you need to advance it:

26 * * *13.8462 degrees (13 degrees 50 minutes 46 seconds)
28 * * *12.8571 degrees (12 degrees 51 minutes 26 seconds)

* * * * With the right hole plate, and the arm and sector arms, it is
easy to set it up to avoid problems. *And that is what an index head
has.

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

* * * * The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. *And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. *(Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. *Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

O.K. That should do it. Did it come with a table of settings
for different divisions? If not, you will need to know how many turns
of the crank for a full turn of the table. Common ratios are 90:1
(larger rotary tables, at least), 40:1 (my dividing head), and I believe
10:1 on some heads.

Good luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Nov 17, 1:17*pm, Jon Danniken
wrote:
On 11/16/2012 08:33 PM, anorton wrote:



This was actually one of my favorite games back when. *It had a special
display with vector graphics, like Asteroids, but in color.

I remember the sit-down SW game at the local billard hall in the
late-seventies. *Seemed fascinating, but I was more into pinball at the
time.

Jon

Actually Star Wars was released in 1983.

One of my friends has the world record on it.

Darren Harris
Staten Island,New York.

On Nov 19, 11:37*pm, "DoN. Nichols" wrote:
On 2012-11-19, Searcher7 wrote:

On Nov 17, 3:45 pm, "DoN. Nichols" wrote:

* * * * [ ... ]

Oops! I forgot not to give approximate numbers. :-)
60 tooth = 2.575"
28 tooth = 1.245"
14 tooth = 0.655

* * * * Not 16-tooth, O.K.

* * * * O.K. *A little different from my calculations. It sounds as
though the crest of the teeth has been shaved a little, No problem as
long as the pitch diameter is correct.

* * * * So the precise OD of the 28-tooth one should be 1.2500" (which
* * * * * * * * matches your 1-1/4")

* * * * The 16-tooth one: *0.750" (3/4" not your 11/16" -- if it is truly
* * * * * * * * 16 teeth.

* * * * The 60-tooth ones: * * *2.5833" *(2" and 9.3333/16", not 9/16")

* * * * [ ... ]

Thanks. Here are some pics of the 60 tooth gear:

http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...

* * * * O.K. *But we knew the count of teeth there. *It was the smaller
ones which I was wondering about -- and you have now told met hat the
smallest one was 14 teeth, not 16, so my calculation for size was wrong.









On Nov 17, 3:56 pm, "DoN. Nichols" wrote:
On 2012-11-17, Searcher7 wrote:

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

O.K. Does the rotary table have a hole plate and arm with
sector arms? If not, it will be tricky for some of the gears. 60 tooh
is no problem. 16 tooth (if I am right about that gear), also no
problem. But the 26 tooth (or was it 28?) will be tricky. For each cut
you need to advance it:

26 13.8462 degrees (13 degrees 50 minutes 46 seconds)
28 12.8571 degrees (12 degrees 51 minutes 26 seconds)

With the right hole plate, and the arm and sector arms, it is
easy to set it up to avoid problems. And that is what an index head
has.

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. (Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

* * * * O.K. *That should do it. *Did it come with a table of settings
for different divisions? *If not, you will need to know how many turns
of the crank for a full turn of the table. *Common ratios are 90:1
(larger rotary tables, at least), 40:1 (my dividing head), and I believe
10:1 on some heads.

I haven't dug out my manual but an internet search says 90:1
http://www.t4i.com.au/R006

The most difficult part will be the gear cutter. (So I'm off to do my
reading).

Thanks a lot.

Darren Harris
Staten Island, New York.

On Tue, 20 Nov 2012 16:50:00 -0800 (PST), Searcher7
wrote:

On Nov 19, 11:37*pm, "DoN. Nichols" wrote:
On 2012-11-19, Searcher7 wrote:

On Nov 17, 3:45 pm, "DoN. Nichols" wrote:

* * * * [ ... ]

Oops! I forgot not to give approximate numbers. :-)
60 tooth = 2.575"
28 tooth = 1.245"
14 tooth = 0.655

* * * * Not 16-tooth, O.K.

* * * * O.K. *A little different from my calculations. It sounds as
though the crest of the teeth has been shaved a little, No problem as
long as the pitch diameter is correct.

* * * * So the precise OD of the 28-tooth one should be 1.2500" (which
* * * * * * * * matches your 1-1/4")

* * * * The 16-tooth one: *0.750" (3/4" not your 11/16" -- if it is truly
* * * * * * * * 16 teeth.

* * * * The 60-tooth ones: * * *2.5833" *(2" and 9.3333/16", not 9/16")

* * * * [ ... ]

Thanks. Here are some pics of the 60 tooth gear:

http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...
http://i290.photobucket.com/albums/l.../Joystick%20Pr...

* * * * O.K. *But we knew the count of teeth there. *It was the smaller
ones which I was wondering about -- and you have now told met hat the
smallest one was 14 teeth, not 16, so my calculation for size was wrong.









On Nov 17, 3:56 pm, "DoN. Nichols" wrote:
On 2012-11-17, Searcher7 wrote:

Oops! Yes I have an HF Mini-Mill. :-) (Along with a rotary table).

O.K. Does the rotary table have a hole plate and arm with
sector arms? If not, it will be tricky for some of the gears. 60 tooh
is no problem. 16 tooth (if I am right about that gear), also no
problem. But the 26 tooth (or was it 28?) will be tricky. For each cut
you need to advance it:

26 13.8462 degrees (13 degrees 50 minutes 46 seconds)
28 12.8571 degrees (12 degrees 51 minutes 26 seconds)

With the right hole plate, and the arm and sector arms, it is
easy to set it up to avoid problems. And that is what an index head
has.

But all I have is an over sized spin index fixture. (www.ebay.com/itm/
350468227596)

The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. (Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

* * * * O.K. *That should do it. *Did it come with a table of settings
for different divisions? *If not, you will need to know how many turns
of the crank for a full turn of the table. *Common ratios are 90:1
(larger rotary tables, at least), 40:1 (my dividing head), and I believe
10:1 on some heads.

I haven't dug out my manual but an internet search says 90:1
http://www.t4i.com.au/R006

The most difficult part will be the gear cutter. (So I'm off to do my
reading).

Thanks a lot.

Darren Harris
Staten Island, New York.
The gear cutter will be easy. You can make the button cutter as
outlined in Law's book and then use that cutter to make a fly cutter
to cut the teeth. You can use water hardening or oil hardening tool
steel. Both are easily available and pretty easy to machine. And heat
treating with a propane torch will work. For that matter, since the
cutters are so small, you could use a gas stove or even an electric
burner.
Eric

On 2012-11-21, Searcher7 wrote:
On Nov 19, 11:37*pm, "DoN. Nichols" wrote:
On 2012-11-19, Searcher7 wrote:

On Nov 17, 3:45 pm, "DoN. Nichols" wrote:

[ ... ]

The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. (Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

* * * * O.K. *That should do it. *Did it come with a table of settings
for different divisions? *If not, you will need to know how many turns
of the crank for a full turn of the table. *Common ratios are 90:1
(larger rotary tables, at least), 40:1 (my dividing head), and I believe
10:1 on some heads.

I haven't dug out my manual but an internet search says 90:1
http://www.t4i.com.au/R006

O.K. That will be 1-1/2 turns per tooth for the 60-tooth one,
Easy to set up with any circle of holes with an even number of holes.

The 20 tooth one is 0.2222 turns per tooth, or 1/4.5, so any
circle with a multiple of 9 holes (likely 18 holes) will do. (The chart
I found later does it a different way.)

As for the 14 tooth one -- that is 0.1556 turns per tooth, I
can't come up with an easy one for that -- check the dividing tables
which should have come with our table. If not -- go into _Machinery's
Handbook_ and see if they have the tables for the 90:1 ratio.

O.K. Here is a site where you can download the table (and
instructions for a similar rotary table).

http://www.minitech.com.au/images/PD...le%20Guide.PDF

And looking at that -- it is doing 6 full turns plus 9 holes on
a 21-hole circle. Interesting approach. That is over 24 degrees per
tooth, so you eventually come around to complete the set with some
number of trips around the gear.


The most difficult part will be the gear cutter. (So I'm off to do my
reading).

Once you find the pressure angle, you have the choice of making
your own cutter for each gear, or buying cutters for each gear. (yes, a
separate one for each of those three gears. A set of cutters consists
of eight total -- each covering a range of teeth. The last of them
covers something like 100 to infinity (I would have to look it up), The
first of them has a range of only three different adjacent tooth counts
IIRC. The shape of the cutter has to be a little different for each
number of teeth. You can sometimes find 1/2 numbered cutters to fill in
the gaps and make a better fitting gear. There is a remote possibility
that your 14 and 20 tooth gears will use the same cutter, but I don't
think so. The tooth count is fairly small, so they probably don't
span the same cutter.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...

O.K. Here is a site where you can download the table (and
instructions for a similar rotary table).

http://www.minitech.com.au/images/PD...le%20Guide.PDF
DoN.

That is a good, simple explanation of the math. If you have trouble
with mixed fractions and know how to set up a spreadsheet you can use
one to create a table of all the full and fractional turns from say 2
to 100 divisions. The low numbers are useful for cutting wrench flats
etc. In OpenOfficeCalc the format code is # ??/??.
jsw

On Nov 20, 10:45*pm, "DoN. Nichols" wrote:
On 2012-11-21, Searcher7 wrote:

On Nov 19, 11:37 pm, "DoN. Nichols" wrote:
On 2012-11-19, Searcher7 wrote:

On Nov 17, 3:45 pm, "DoN. Nichols" wrote:

* * * * [ ... ]









The rotary table is a far better choice than this. The finest
rotation you can accomplish with the spin indexer is 1 degree. And even
for the 16 tooth gear, you need 22.500 degrees -- that half a degree you
can't get on the spin indexer. (Yes, it would work with the 60 tooth
gear, which only requires 6 degrees advance for each tooth. Still a
little tricky to calculate the position of the pin for each one.

As far as "hole plate and arm with sector arms". I have a rotary table
with dividing plates that I haven't used yet. In fact, this one:
www.ebay.com/itm/321022783132.

O.K. That should do it. Did it come with a table of settings
for different divisions? If not, you will need to know how many turns
of the crank for a full turn of the table. Common ratios are 90:1
(larger rotary tables, at least), 40:1 (my dividing head), and I believe
10:1 on some heads.

I haven't dug out my manual but an internet search says 90:1
http://www.t4i.com.au/R006

* * * * O.K. *That will be 1-1/2 turns per tooth for the 60-tooth one,
Easy to set up with any circle of holes with an even number of holes.

* * * * The 20 tooth one is 0.2222 turns per tooth, or 1/4.5, so any
circle with a multiple of 9 holes (likely 18 holes) will do. *(The chart
I found later does it a different way.)

* * * * As for the 14 tooth one -- that is 0.1556 turns per tooth, I
can't come up with an easy one for that -- check the dividing tables
which should have come with our table. *If not -- go into _Machinery's
Handbook_ and see if they have the tables for the 90:1 ratio.

* * * * O.K. *Here is a site where you can download the table (and
instructions for a similar rotary table).

* * * *http://www.minitech.com.au/images/PD...le%20Guide.PDF

* * * * And looking at that -- it is doing 6 full turns plus 9 holes on
a 21-hole circle. *Interesting approach. *That is over 24 degrees per
tooth, so you eventually come around to complete the set with some
number of trips around the gear.



The most difficult part will be the gear cutter. (So I'm off to do my
reading).

* * * * Once you find the pressure angle, you have the choice of making
your own cutter for each gear, or buying cutters for each gear. (yes, a
separate one for each of those three gears. *A set of cutters consists
of eight total -- each covering a range of teeth. *The last of them
covers something like 100 to infinity (I would have to look it up), The
first of them has a range of only three different adjacent tooth counts
IIRC. *The shape of the cutter has to be a little different for each
number of teeth. *You can sometimes find 1/2 numbered cutters to fill in
the gaps and make a better fitting gear. *There is a remote possibility
that your 14 and 20 tooth gears will use the same cutter, but I don't
think so. *The tooth count is fairly small, so they probably don't
span the same cutter.

* * * * Good Luck,
* * * * * * * * DoN.

--
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* * * * * *--- Black Holes are where God is dividing by zero ---

Thanks a lot.

Darren Harris
Staten Island, New York.