Wheel and Pinion Depthing

[Steve CrowParticipant @stevecrow46066]

I should of made clear that these are for (slow) motion work. The 73 T wheel revolves one a year. I'm sure that involute is legitimate for this and not "all wrong for a clock".

I have had the Wild book for some time now and have copied quite a few of the fixtures and fittings featured. I also have the Gears for Small Mechanisms.

It's not so much the theory I'm so concerned with. I have a set of Mod 0.3 cutters and it's all about making the most of those.

I would love to do everything in cycloidal with Thornton cutters but £££.

Steve

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Steve Crow on 12/09/2022 22:32:24:

… I have a set of Mod 0.3 cutters and it's all about making the most of those.

 

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With the greatest respect, Steve … I think that may be what’s causing your depthing difficulty

MichaelG.

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Edited By Michael Gilligan on 12/09/2022 23:44:25

[Michael GilliganParticipant @michaelgilligan61133]

Have you tried this, Steve ?

**LINK**

Online Involute Spur Gear Builder v2

… from that very clever chap, Dr. Rainer Hessmer

MichaelG.

[Steve CrowParticipant @stevecrow46066]

Posted by Michael Gilligan on 13/09/2022 08:54:59:

Have you tried this, Steve ?

**LINK**

Online Involute Spur Gear Builder v2

… from that very clever chap, Dr. Rainer Hessmer

MichaelG.

I have used that site before. Here's what it shows for the gears in question –

The thing is, I don't have a depthing difficulty as such. The gears run smoothly and freely with little backlash and I can live with the extra depthing distance.

But I don't like the look of the tooth profile on the pinion.

Steve

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Steve Crow on 13/09/2022 11:51:27:

… The thing is, I don't have a depthing difficulty as such. The gears run smoothly and freely with little backlash and I can live with the extra depthing distance.

But I don't like the look of the tooth profile on the pinion.

Steve

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I’m really sorry to labour this, Steve … and I will leave you in peace after this posting:

You do have ‘a depthing difficulty as such’ : Your pinion is not sitting at the right depth in the wheel.

Just compare your photo with the drawing.

If you are not bothered about the proper involute action, then the teeth could be any old shape you like, and you can run them at any depth you fancy. … but in that case, your opening question would seem irrelevant.

MichaelG.

[Steve CrowParticipant @stevecrow46066]

No problem Michael, I appreciate it. I need all the help I can get!

What bothers me about the drawing is that there appears to be no clearance or play. There are 5 points of contact including one on the root of the pinions. It also seems that the tooth depth is only 2 x Mod.

I scanned the wheel and pinion again and overlaid the outline from the drawing to see how profiles compare –

They are a lot closer than I thought.

Steve

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Steve Crow on 13/09/2022 14:03:04:

[…]

What bothers me about the drawing is that there appears to be no clearance or play. […]

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Although in practice it is impossible to achieve, that is hypothetically correct : That’s what I had in mind when I wrote ‘the proper involute action‘ … in a perfect world the action would be pure rolling without scuffing.

Life, of course, is not perfect, but it should be possible to get closer than your current depthing.

MichaelG.

[Author]

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