RE: [CAD_CAM_EDM_DRO] Improving accuracy on mini-mill? (lapping?)

Abbey,

I am inclined to agree with Roger and Bruce. Lapping can improve
repeatability, but not accuracy... since it's not controlled.

Some parts are lapped together. Spin indexes and gears come to mind.
A progressive compound is used. It stops cutting after the abrasive
is worn down.

But lapping is used for just the last few tenths at most. It is also done
when light loads are expected.

For heavily clamped dovetail gibbs high spots are actually a good thing.
They allow the other areas to hold oil. Note that precision machine gibbs
are ground and scraped...almost never lapped.

Do read up on scraping from the many references. I have some on my site.
Although called scraping grinders and abrasive papers are often used as
basic tools.

The advantage is that a reference surface provides accuracy as well as
repeatability.


Leslie M.Watts
L M Watts Furniture
Tiger Georgia
(706) 212-0242

Main page:
http://www.lmwatts.com
Engineering:
http://www.lmwatts.com/shop.html
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http://www.lmwatts.com/forsale.html
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http://www.lmwatts.com/signwp.html


-----Original Message-----
From: Abby Katt [mailto:cnc@...]
Sent: Tuesday, March 22, 2005 6:02 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: RE: [CAD_CAM_EDM_DRO] Improving accuracy on mini-mill?
(lapping?)



Roger,

But I wasn't really thinking of using say.. 60 grit..

I was thinking more of using something fine (ie 600 to 1200 grit), to smooth
out the bearing surface and gibs, so that I could reduce friction, allowing
me to tighten them more and gain better rigitity. If I used a small enough
grit size, wouldn't it just remove the current irregyularities from the
surface and even it out more, so that they still more or less defined the
same plane, but moved with less friction?

I've heard of a few people using lapping.. Does anyone else have any
experience here?
A worthy-try, or a just plain bad idea?

Thanks!
Abby