From: James P Crombie 
To: Atm List 
Reply-To: James P Crombie 


Hermit

  Lapping will not eliminate all of the periodic error but it should
reduce it and smooth it out a bit.  A lot will depend on how accurate your
worm is to start will and how bad the gear is.  If you have a very accurate
worm and the gear is only out a bit then the worm will lapp the gear in
nicely.  If the gear is out substantially then it will take more time to
lap properly and may affect the worm by wearing it unevenly.
   I would suggest using several grades of lapping compound eventually
getting down to a polishing compound.  The only thing to watch for is using
excessive pressure as you could imbed the grit into the alum and it might
wear the worm continuously.  I have used some nice diamond compounds that
will give metal a mirror finish very quickly. But mixing up you own
abrasive paste from 500, 12micron and CeO should work well, if only a
little slower.

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Subject: Re: ATM Lapping In Worm & Wheel

Quoting J&S :



How much does this help with periodic error, not just fit.  And would finer
grades help too?

Hermit
Holed up in Youngstown, Ohio
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James P Crombie

Summerside                   Machinist
Prince Edward Island         Amateur Astronomer
Canada                       3D Designer

E-mail                       jpcrombie{at}pei.eastlink.ca
Astronomy webpage            http://www.jamescrombie.com
Rhinoceros 3D webpage        http://www.jamescrombie.com/rhino/
Mirror Grinder page          http://www.jamescrombie.com/pics/
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