76 trigger sear ,,how hard ??

[Slamfire]

 From some of my other threads ,ya'll will notice that I'v been building up spare parts for my 76 " Chaparral ".. this week ( snow & col-dder ), I made a new trigger sear. Now I need to case harden it ,, it is made of scrap low carbon ,, but what hardness does it need to be,, 30-55- . Not sure of original sear's hardness ,, but it is still working good ( a few hundred rds. ) I made the new sear about 4-6 thousands longer ,, now the firing pin does not drag on top of the hammer as it returns to  but still locks in the full cock notch,, the action works smoother ,,also lightened  the trigger pull .

  coffee's ready ,, Hootmix.

[Kent Shootwell]

When you case harden mild steel the core will remain soft and the carbon rich surface can be made quite hard. The depth of the case needn't be very deep to give long life to the wearing points and the core will less prone to cracking. Plus the hard contact point will make for a smoother operation.

[Slamfire]

 Hey Kent,, yes sir that is my intent ,, bought a small bag of BBQ charcoal to use .Will holler back when finished.

smoke'm if ya' got'm ,, Hootmix.

[kwilliams1876]

If using kasenite on mild steel, hang the sear on a wire. use your torch to let the powder "simmer" on it at a red heat for a few minutes and quench in water. The next time you build a sear starting with a piece of tool steel would be a better choice, and actually easier to ensure a good part
for all your work.
I too made and modified my chappy parts to "get it right"
best
kw

[Gabriel Law]

Once you are satisfied that your case hardening has produced a glass hard surface, and a file won't cut it, put the part into a toaster oven, or the like, at 375 deg. F for an hour.  A polished part will come out straw coloured.  That will still leave the surface hard enough to wear well, but will take care of an issue where the case depth makes the tip of the sear fragile.