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?


How about the old stainless steel cleaner, 'Barkeeps Friend'? It
says it is abrasive, but not how much. I've seen it used in kitchens
for years to keep old stainless steel sinks & tables clean and looking
good.

http://barkeepersfriend.com/products.htm

http://barkeepersfriend.com/BKF_MSDS_01_09.pdf


--
You can't have a sense of humor, if you have no sense!