Do you case harden your lock screws?

[Artificer]

The topic about the sidenails brought this questio to mind.

When you all make a lock screw with a longer body and/or take some from the underside of the head of the screw, then get the screw to where it is tight without binding the parts - do you case harden the modified screw/s?

On some emergency fixes, I was not able to case harden the screws after adjustment.  Had to get the shooter back to the line to compete.  I usually case hardened the screws when I could, thinking that was especially good for the body of the sear screw to act like a hardened bearing.  On the bridle and sidelock screws, I thought that would keep them from wearing into the lock plate and thus allowing them to be tightened sooner or later back to where they would bind.  Hope this makes sense.  

Never had any complaints after casehardening the modified screws, but I have wondered if hardening them would cause them to wear into the lock plate faster.  Does anyone have experience with that?    

Thank you,
Gus

[Stophel]

I only bother case hardening the sear screw.  I don't worry about it wearing the plate, since I harden it too.   

Be sure to temper the screw at least a little.  They can case harden through and through (even with Kasenit), and I have snapped one before.

[Artificer]

Chris,

That bring aother question to mind.  Are most assembled civiliian style commercial lock plates case hardened when you buy the assembled lock?
Most of what I have worked on was larger military (both repro and originals) or original civilian locks and they usually had case hardened lock plates.

I also liked to case harden the bridle screws as too many guys would tighten them too much even when shown how to do it properly.

Good advice about tempering them,  I do that but didn't think to mention it.

Thanks, Gus

[Stophel]

No.  Chambers, Davis, etc. lockplates are not hardened.  They are made of 8620, as I recall, and case harden easily.   

[Artificer]

Thanks Chris,

That's good to know.

Gus

[Dphariss]

I polish and caseharden them all then re-polish and heat to blue.
I have had a number chip at the screw slot otherwise. It also helps keep the threads from chipping as as well.

Dan

[Artificer]

I polish and caseharden them all then re-polish and heat to blue.
I have had a number chip at the screw slot otherwise. It also helps keep the threads from chipping as as well.

Dan

Good advice and thank you.  I always polished the sear screw before tempering, but I should have thought about doing it on the other screws as well. 

I'm glad to know I need to case harden and anneal many lock plates now.  As inexpensive as many complete commercial locks are, I should have realized they would not have been already done.

[Jim Kibler]

Artificer,

Putting cost aside, it wouldn't be too practicle for lock manufacturers to provide plates case hardened.  It would be extremely difficult if not impossible to drill and tap for the lock bolts in a hardened plate.  Also it would be pretty painful to polish the plate down from the cast finish.  Finally any modifications or changes that might be made to the plate would be much more difficult if it were hardened.  The best way is to completely finish the lock and then case harden if desired.  I like to do this on all the locks I use.   The plate, cock, top jaw and top jaw screw get case hardened (carburized).  If I make a frizzen I just use mild steel and carburize this as well.

[Dphariss]

Would make them tough to engrave too.

Dan

[Artificer]

Jim,

You wrote a bunch of valid and excellent points as did Dan. 

I hope everyone understands I'm not blaming any lock manufacturer for not case hardening their lockplates - FAR from that.  I find it a bit astounding that the good lock manufacturers today are still providing a quality product for virtually the same price (or less) in current "real" dollars as they did in the 70's and 80's. 

Thanks again, Gus