On Sun, 17 May 2009 21:21:33 -0700, Michael Koblic wrote:

Lapping seems to be a term that encompasses several different processes
of similar nature.

I am interested specifically in the recommendations to lap the ways of
lathes and mills. There seems to be a variety of ways people achieve
this: From dedicated lapping compounds obtained in Auto part stores
(which here nobody has heard of) to mixing up a scouring powder with oil
to make a lapping paste. It brings up several questions:

1) When does lapping stop and grinding starts (Permatex make a "valve
grinding compound" which some people use for lapping)? 2) What is the
maximum/minimum grit suitable for lapping? 3) Why isn't using ultrafine
steel wool/Scotchbrite pad "lapping"?

FWIW I tried to make a 3/4" shaft turn more smoothly in bronze bearings.
Not having anything "lapping-like" to hand I mixed up Fast Orange with
oil and used that. It contains pumice and GOK what the grit of that is.
The shaft is smoother. I think.

BTW it is now virtually impossible to get the old scouring powders for
cleaning - everybody is so proud that their product is "scratch free".

While browsing in the Auto part stores I found several cleaning pastes
which contain abrasives. Would they be suitable? Too harsh?

Where's "here" for you?

In the US you can get lapping compound (and diamond grinding/lapping
compound) from McMaster and from Small Parts, Inc.

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