Doglock lock problems...

[TRP]

So, I have this new to me doglock British musket reprodiction. Not an Indian one. Here's the post about it: https://www.muzzleloadingforum.com/...musket-supposed-to-be-and-who-made-it.185978/

The lock has a problem, maybe- I'm too ignorant to know if it is supposed to be like this. The tumbler, between the half cock and cock down position, has a sort of flat spot- actually a little depression. When cocking the lock there's a definite harder effort spot there, and when letting down the same spot interrupts the smooth fall of the cock. The sear nose gets hung up and bumps there, but the cock does go on and finish the stroke. My experience of sidelocks is that the fall of the cock is smooth, but maybe the early ones had an intentional rough spot? Maybe to soften the impact of the flint?

The lock is otherwise of, to my eye, good modern construction. Aside from this, everything works smoothly and there don't appear to be any spots where the parts interfere or mark each other. None of the springs rub on the lock plate.

I've added pictures of the lock inside, and as best I could pictures of the flat spot.


View attachment IMG_2022.JPG

Sear nose is at the "flat spot"-

You can see that the flat spot is actually below the curved surface of the tumbler, it's not been brightened by friction with the sear nose.

I don't know who made the lock, I bought it second hand. I would think the fix, if it is not meant to be this way, would be to stone the tumbler surface out to a smooth curve and eliminate the flat spot/depression. I don't think heat treatment would be an issue, the sear nose just rests on the surface- although obviously the sear spring is very stout!

Thank you for your assistance.

 

[rich pierce]

Smooth it. Normally the trigger should keep the sear nose lifted off the tumbler belly. Do you have a very light trigger pull?

 

[TRP]

Thank you for the quick response! The trigger pull is heavy, I am sure the massive sear spring contributes to that.

 

[rich pierce]

Heavy trigger pulls are dependent on the sear spring, the angle of the full cock notch, and the position of the pivot pin for the trigger.

Is it very hard to release the sear when the lock is in your hand? If so that likely means the issue is sear spring or full cock notch angle, or both.

Sometimes the full cock notch angle is not aligned with the radius to the tumbler axle. With the mainspring out, push forward lightly on the cock while releasing the sear from full cock. “Firing” it in the hand without a mainspring. If the cock is levered backwards very slightly, the full cock notch needs fixing. In that instance you’re fighting the mainspring when releasing the sear.

Ok let’s say it’s the spring. Is the end of the working tip polished? Is the sear bar polished where the tip of the spring slides on it? Is the tip of the spring jamming on the knuckle or boss of the sear?

If these are good or don’t fix it, lighten the sear spring by thinning very gradually. It may be too hard to file. In that case get or use a cheap set of diamond files off eBay. Remove 10% of the thickness of the working arm at a time, preserving tip thickness to some extent, keeping a nice taper.

Each time, test it in the gun. You’ll sort it out.

 

[TRP]

Thank you so much! that gives me something to work on today. But smooth out the tumbler depression first, right?

 

[rich pierce]

Yep

 

[FlinterNick]

So, I have this new to me doglock British musket reprodiction. Not an Indian one. Here's the post about it: https://www.muzzleloadingforum.com/...musket-supposed-to-be-and-who-made-it.185978/

The lock has a problem, maybe- I'm too ignorant to know if it is supposed to be like this. The tumbler, between the half cock and cock down position, has a sort of flat spot- actually a little depression. When cocking the lock there's a definite harder effort spot there, and when letting down the same spot interrupts the smooth fall of the cock. The sear nose gets hung up and bumps there, but the cock does go on and finish the stroke. My experience of sidelocks is that the fall of the cock is smooth, but maybe the early ones had an intentional rough spot? Maybe to soften the impact of the flint?

The lock is otherwise of, to my eye, good modern construction. Aside from this, everything works smoothly and there don't appear to be any spots where the parts interfere or mark each other. None of the springs rub on the lock plate.

I've added pictures of the lock inside, and as best I could pictures of the flat spot.


View attachment 352940

Sear nose is at the "flat spot"-
View attachment 352944


You can see that the flat spot is actually below the curved surface of the tumbler, it's not been brightened by friction with the sear nose.View attachment 352949

I don't know who made the lock, I bought it second hand. I would think the fix, if it is not meant to be this way, would be to stone the tumbler surface out to a smooth curve and eliminate the flat spot/depression. I don't think heat treatment would be an issue, the sear nose just rests on the surface- although obviously the sear spring is very stout!

Thank you for your assistance.

Your lock was made by miroku in japan, and then was defarbed by someone into a dog lock.

In looking at the lock the plate was cut, elongated and welded. The welding of the plate probably has had an impact on the locks designed geometry causing the sear to engage the tumbler closer than it should have.

Rich’s advice is good to follow.

 

[FlinterNick]

So, I have this new to me doglock British musket reprodiction. Not an Indian one. Here's the post about it: https://www.muzzleloadingforum.com/...musket-supposed-to-be-and-who-made-it.185978/

The lock has a problem, maybe- I'm too ignorant to know if it is supposed to be like this. The tumbler, between the half cock and cock down position, has a sort of flat spot- actually a little depression. When cocking the lock there's a definite harder effort spot there, and when letting down the same spot interrupts the smooth fall of the cock. The sear nose gets hung up and bumps there, but the cock does go on and finish the stroke. My experience of sidelocks is that the fall of the cock is smooth, but maybe the early ones had an intentional rough spot? Maybe to soften the impact of the flint?

The lock is otherwise of, to my eye, good modern construction. Aside from this, everything works smoothly and there don't appear to be any spots where the parts interfere or mark each other. None of the springs rub on the lock plate.

I've added pictures of the lock inside, and as best I could pictures of the flat spot.

As you can see in this picture, your lock is a miroku charleville lock.

The tumblers on these wear out because the mainsprings have over an 85 lb pull.

This one has never been on a gun.




View attachment 352940

Sear nose is at the "flat spot"-
View attachment 352944


You can see that the flat spot is actually below the curved surface of the tumbler, it's not been brightened by friction with the sear nose.View attachment 352949

I don't know who made the lock, I bought it second hand. I would think the fix, if it is not meant to be this way, would be to stone the tumbler surface out to a smooth curve and eliminate the flat spot/depression. I don't think heat treatment would be an issue, the sear nose just rests on the surface- although obviously the sear spring is very stout!

Thank you for your assistance.

 

[TRP]

That is exactly the problem! The sear and tumbler were effectively too close. I've fixed that, and it doesn't have the hesitation any longer. Thank you!

New problem, though. With a wooden false flint, everything works as it should. With a real flint, though, the frizzen doesn't snap open all the way- it hangs up about 3/4 of the way open with the cock about 3/4 of the way down snagging it. It's like the friction of the flint robs the power of the snap. Too much frizzen spring? Or should I just send it to a tuner?

 

[rich pierce]

Glad you’re making progress.
Reasons for frizzen not opening with flint strike:

Frizzen is just too hard to open anyway. Frizzen spring too strong, frizzen binding, no lube.

Mainspring too weak. Unlikely.

Flint striking too high or low on frizzen. You want it to strike about 2/3 of the way up.

Frizzen is soft and the flint is digging in. Test by trying to cut the frizzen face with a file. It should not cut it, but skate off.