tuning a lock

[Evan Ebersole]

I have a small L&R lock that will not stay on full cock and I don`t know what to look at
Tumbler or sear?

 

[Dave K]

Look at both. Also see if it will hold cock out of the mortise. Is there any wood interferring with it's function in the mortise?

 

[SusieB]

Thats an excellent observation! Is the lock a problem in or out of the mortise!? If it works okay in your hand, but won't hold cock in the inlet, then wood is interfering with the sear. If it is a problem still, then look at the ledge on the tumbler and the length of the sear nose. Remove the mainspring so you can study the action to see which surface is inferior. Let us know what you find.

 

[Evan Ebersole]

Thank`s for the help. The tumbler was rounded off
and it would not stay cocked out of the gun a little work with a stone and it works great.

 

[dlemaster]

Lost in time
If the tumbler rounded off and stoneing it got it working again, odds are the tumbler is too soft and the problem will return. You will need to reharden and temper or use Kasnite to get enough carbon into the steel to reharden and temper.
Hope this helps.

Regards, Dave

 

[Zonie]

Before you try Kasnite, try your file on the rounded contour just below the full cock notch.

The file shouldn't leave a scratch let alone remove any material.

I can't say first hand because all of my L&R locks have been great, but, I have heard that L&R have had some locks slip out which leave more than a little to be desired.
If your lock was not ground properly at the factory, it could be fully hardened but still have the rounded area you saw.

If the tumbler is soft, the Kasnite would fix the problem but just remember to quench the part in oil .
The tumbler in most modern locks is made of a oil hardening steel and a water quench will crack or break it.