View Single Post
Old December 22, 2011, 11:27 AM   #24
warbirdlover
Senior Member
 
Join Date: December 13, 2009
Location: central Wisconsin
Posts: 2,324
Quote:
Sorry for this, I don't mean to hijack this thread, but Longdayjake's link shows a guy taking metal off of the sear? I was told by a master machinest and master gunsmith that you never, ever take metal off the sear as it is heat treated and the hardest part of the sear is right on the edge. By removing that you are creating a trigger that at some point is not going to operate correctly since it'll round off the edge. Thoughts?
Since I'm a retired metallurgist this could be true if the part has been "nitrided". This is a very hard, very "shallow" heat treatment. If it has been carburized or induction hardened it would be much deeper and probably not an issue. It also might just be chrome plated which wouldn't be very deep also.

The master gunsmith and master machinist told you right! Here is approximate "depths" of hardness for different heat treatments FYI. These can be varied but these are more common... Surface hardness would be HRC60+ and the "depth" is where the hardness drops down to HRC 50. The heat treatment used depends also on the steel chemistry and material type (stainless steel, alloy steel, plain carbon steel, etc).

Carburizing - usually over .020" deep
Carbonitriding - around .015-.020" deep
Nitriding - typically around .010" deep
Ferritic Nitrocarburizing - .005" deep
Induction hardening - .020+

Not a heat treatment but chrome plating - .010+

Last edited by warbirdlover; December 22, 2011 at 11:35 AM.
warbirdlover is offline  
 
Page generated in 0.02509 seconds with 8 queries