Subject: Gear geometry

From: [email-masked] (Dave Larsen)
Date: Thu, 30 Sep 1993 16:16:45 GMT

I'm looking for a mathematical description of gear teeth.

Can anyone point me at a easy to find book?

David A. Larsen              Computer & Information Services 
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University of Minnesota         
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From: [email-masked] (Tim Kirby)
Date: 30 Sep 93 20:32:31 CDT

Dave Larsen ([email-masked]) wrote:
: I'm looking for a mathematical description of gear teeth.
: 
: Can anyone point me at a easy to find book?

You could try "A Treatise on Gear Wheels" by George B. Grant,
one of the Lost Technology Series, reprinted by Lindsay Publications Inc.

It told me far more than I wanted to know... :-)

Tim
--
Tim Kirby --------- Cray Research Inc., Eagan, MN, USA ---------- [email-masked]
Disclaimer: I disclaim, therefore I am. Be warned ...
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From: [email-masked] (Thomas Clarke)
Date: 4 Oct 1993 12:59:03 GMT

If you just want to make spur gears, you may not need a book.

As I understand it gears are made with a hob, like a tap
but with different profile on cutting teeth.

All spur gears mesh with a rack, a gear with infinite radius,
so if the hob has cutting teeth shaped like the rack, it will
cut a spur gear.  I'm sure there are special machines but
the hob might be mounted in a tool post grind on a lathe
to take cutting passes from the gear blank.  Repeatedly
indexing the blank will eventually form the entire gear.

The amateur telescope making trick for making big worm
wheals is to chuck a tap in the lathe and mount blank
on the cross slide.  The tap rotates the blank as it cuts
so a worm wheel is formed that mates with the corresponding
bolt.  Increasing the depth of cut eventually produces an
integral number of teeth.  Problem is the number of teeth
can be one or two off from what you aim at.
--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
3280 Progress Drive, Orlando, FL 32826-0544
(407)658-5030, FAX: (407)658-5059, [email-masked]