"Anthony" wrote in message
...
Dave Hinz wrote in news:3r7slrFi6vhvU1
@individual.net:

On Thu, 13 Oct 2005 12:54:03 -0700, Eric R Snow
wrote:

Check to see if thickened oil is making it drag.

Once that starts happening, what is the fix? I've got two which are
a bit...sludgy... one a Starett, the other a Mitotoyo. Can't use 'em,
can't sell 'em, and certainly can't toss 'em.


Either IsoPropol Alcohol, or Acetone will take care of the problem. Be
sure to use some 3 in 1 oil on them after cleaning.


Most commonly available isopropyl alcohol contains a fair amount of water,
typically around 30%. I wouldn't use it for cleaning a precision tool.

Acetone will do the job if you are able to soak the part. But trying to
apply acetone with a swab will be frustrating because the acetone evaporates
so quickly, that you might not get enough saturation to effectively
dissolve, dilute, and remove the gum. Methyl Ethyl Ketone (MEK) is a little
better as it does not evaporate as quickly as acetone. But the biggest
problem with using either acetone or MEK is that they are too aggressive:
they will remove paint (e.g., the coloring in the engraved numbers on a
micrometer) and they will damage plastic parts (e.g., the lens on your
indicator). Also, acetone/MEK will strip the metal parts of ALL protective
oils, so if you don't immediately re-oil (and cover every spot) you run the
risk of rust (lack of barrier film and water displacement) and wear (lack of
lubrication).

I use fresh, high-quality kerosene for removing gummed-up oil from tools and
instruments. It evaporates very slowly, so you can apply a small amount with
a swab and give it time to dissolve the gum/varnish. And because it's a mild
solvent, you can soak parts if necessary. Either way, there's little risk of
damaging any paint or plastic. And afterwards, the kerosene leaves a light
(temporary) protective oily film behind, giving you time to properly oil the
parts.

Regards,
Michael