Percussion lock help?:

[Scota4570]

I see a knife edge sear and a worn full cock notch.  The full cock notch needs to be angled more llike my read line.  The angle will be such the cock cams back just a hair.  It should be the angle 90* from the sear pivot screw center to a  bit above the outside edge of the sear notch.  The sear nose should be flat at fill the full depth of the full cock notch, not a knife edge.  There should be 100% contact between the two.  Forget about files.  To aggressive and crude.

 A  fine diamond sharpening lap is a good tool.  Back cut the metal backer to make a sharp edge on cutting side of the lap.  Hold the tumbler in a vice and rig up a way to jig the lap to run flat and to the correct angle.  Do the same on the sear nose.  No free hand, no files, and certainly no Dremil tools.   You can test the angles with the springs out.  The amount of material that needs to be removed is only a few thousands or an inch.   When it works remove the knife edge of the sear and tumbler with about one stroke of the lap.  IF you don't it will break off in use.    Good luck.

[shifty]

  Pears to me it could use a good cleaning to.

[Wingshot]

  Pears to me it could use a good cleaning to.

That’s an understatement. I just recently picked up this piece and went out to shoot it last weekend when I discovered the problem. When I pulled it and the triggers, they were filthy. I’ll give it a thorough and proper cleaning.

[Bob Roller]

Appears that way to me as well. Too, the sear's nose appears to be rounded in the picture.

The full cock position look "scooped"out to me and that close picture
is a good one.A few strokes with a fine cut Barrete File would fix it but
that isn't a real common tool.

Bob Roller

[Wingshot]

Just to update: my friend Roy Scott took my lock and set about putting a master class on as he lapped and honed the internals, tuned the lock and triggers. He then handed back a safe, quick and crisp caplock .32 that I can’t wait to shoot again. Thanks to all for the look and helpful suggestions but most of all, thank you Roy!

JA

[Acer Saccharum]

JA< it looks like you have 'A' in your lock, when you really want 'C'. If you go too far with your tumbler notch stoning, you could end up with 'B', and a 10 lb trigger pull.

[Wingshot]

JA< it looks like you have 'A' in your lock, when you really want 'C'. If you go too far with your tumbler notch stoning, you could end up with 'B', and a 10 lb trigger pull.

That’s a great diagram Acer, I’m saving that. Thank you.

[Randall Steffy]

Thanks Scota4570, for a description of a practical and mechanically sound procedure to stone the sear and tumbler. And thanks to Acer for taking the time to show a graphic of the angles at play here. These small details are incredibly important to a safe firearm and we cannot be too careful that this set of details are handled correctly by anyone using or altering them. Thanks everyone who understands and promotes the safe lock.

[Acer Saccharum]

When Talking about safety, when you look at the lock/sear engagement in "A", without the sear spring pushing the sear into the full cock notch, the sear won't stay engaged by itself. If the sear spring should fail, the gun will fire all by itself. The geometry of the tumbler notch is such that it's trying to wedge the sear out of the notch all the time.

When the gun is at full cock, and you have the 'A' sear engagement, a push on the back of the hammer will overcome the sear spring, and the gun will fire.

If your gun is set up like "A", and you fall in the woods, or drop your gun, your gun could go off accidentally.

[Wingshot]

When Talking about safety, when you look at the lock/sear engagement in "A", without the sear spring pushing the sear into the full cock notch, the sear won't stay engaged by itself. If the sear spring should fail, the gun will fire all by itself. The geometry of the tumbler notch is such that it's trying to wedge the sear out of the notch all the time.

When the gun is at full cock, and you have the 'A' sear engagement, a push on the back of the hammer will overcome the sear spring, and the gun will fire.

If your gun is set up like "A", and you fall in the woods, or drop your gun, your gun could go off accidentally.

“A” was exactly the condition my lock was in when I initially posted and yes, at that point the rifle was unsafe and fortunately my safe muzzle discipline prevented any kind of tragic mishap when I was out shooting that day. After disassembly and some deft honing work the tumbler now resembles “C” and the cock cannot be forced off the full cock position. Many of the lock parts required some cleaning and polishing and I’m now satisfied and confident that I’ve got a safe firearm.