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Old 04-16-2011, 06:46 AM
scooter123 scooter123 is offline
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I don't buy it. While I'm not certain that they are MIM, I suspect that the thumb piece for the cylinder release on the new stainless revolvers are MIM. It's a small part that could easily be produced with the MIM process at what would be a fairly easy cost savings.

I've polished these parts on my 610 and 620 and the result is they look chrome plated. However, I did find that the surface would take on a "marbled" look when I tried to refine the finish by simply using a polishing compound. What I did to get a good and level high polish was to wet sand from 800-1500 grit, then further refining with a Diamond Lapping Paste, and finally do the final polish with a high grade polishing compound. Point is, IMO it can be polished, however the approach used has to follow the traditional steps for polishing without any shortcuts.

I'll also note that I wouldn't think about or suggest polishing internal MIM parts. I don't know the hardness or material specifics for the rebound slides in my MIM revolvers but do know they are very hard. In addition, fully polishing a "working" surface is NOT good practice, lubricant's don't "wet out" well on fully polished surfaces and you actually want some scratches to retain lubricants. I've been designing and building industrial machinery for a lot of years and if you have gibs and ways that have become fully polished by use they will then start to gall rather quickly unless you change to a lubricant with a high degree of "wetting" agents and that's only a short term "crutch". The best long term fix is to grind or "shape" the running surfaces to provide those essential scratches to retain and spread your lube.

Last edited by scooter123; 04-16-2011 at 07:00 AM.
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