tumbler problem

[Wayne Wynn]

I recently bought a Pedersoli side by side percussion shotgun in great looking shape. I was however,not happy with the trigger pull on the right hand lock. Also the hammer on the lock,when on half cock was back much farther than the hammer on the left side at half cock. This bugged me!  The trigger pull on the right lock felt like 15 pounds! I figured no problem here , I'll just heat the tumbler cherry red and let it air cool,then I could deepen the half cock notch and work on the full cock position with my file and stones
               After heating the tumbler and letting it cool I tried to file it. No go!! Hard as a diamond , my file did nothing ,it just skidded across it. I couldn't believe it! I tried heating it a second and third  time ---------- NOTHING
              What gives?? I've worked on original tumblers and found that many times you can file them without drawing out the temper
             How can I draw the temper out so that I may work on it??
                             Thanks, Wayne

[jerrywh]

Put the tumbler in a piece of pipe. Heat the pipe and the tumbler to a good red heat [1500°]  Let it cool slowly.  It's cooling too fast.  the heat from the pipe will slow the cooling rate.  If that don't work - Change Churches.

[Acer Saccharum]

I have had luck letting parts cool slowly, by burying in dry sawdust. The smouldering stinks to high heaven, so do this outside.

I have a dremel with a narrow cut-off wheel, that I use for cutting the half cock notch deeper on hardened tumblers. The wheels are brown abrasive, about .025 thick, and run on an arbor, also sold by dremel.

You may need a new tumbler, after heating and cooling so many times. It may have developed stress fractures that are invisible to the eye.

Acer

[Dphariss]

There are air hardening steels. Heating them and air cooling is how they are hardened.
In my (much) younger days I made a knife from a piece of wagon seat spring. Forged it out but could not file it. Not glass hard but hard enough a file would barely cut it. I left it in the forge to cool, and this worked
It is always best to anneal steel by heating red then covering with wood ash to slow the cooling.
OR heat to dull grey, past blue to draw them back. This will generally allow them to be filed etc.

Dan

[hanshi]

A little off subject but a few years ago I bought a very nice Pedersoli perc sxs and had the very same problem with the right hand lock.  The halfcock notch seems to be okay but everything else you described is there.  Is this characteristic of Pedersoli sxs?

[Gene Carrell]

I too have had a similar problem with the trigger pull on one of their doubles. The sear notch was at an angle such that  pulling the trigger caused the hammer to move back considerably. Stoninh the notch took care of it. Sounds like a systemic problem to me.

[Wayne Wynn]

After reading the first post by jerrywh I hurried out to my shop to have a go at it! It worked great!!  First I heated the tumbler cherry red , then dropped it into an 8" piece of 1" pipe, then heated the pipe red. When I was done heating the pipe I buried it in a box of vermiculite. It stayed real hot for acouple of hours. when it finally cooled I had no trouble filing it. Thanks Jerry! And everyone else who responded