Author Topic: cap & ball revolver trigger (Read 693 times)

unspellable · « **on:** July 21, 2005, 05:13:47 AM »

I have a Colt style cap & ball with the creepiest trigger I've ever seen. On examining the innards, I see where the creep comes from, but it's less obvious what to do about it.

If I reduce the sear/notch width or engagement I reduce the creep by the same amount. Trouble is, by the time the creep is reduced to a reasonable level, the engagement will be very small and this strikes me as unsafe.

I am wondering what role the angle of the mating surfaces plays in all this.

This is obviously something one wants to have well thought out before attacking it with a stone.

Any advice?

KSR · « **Reply #1 on:** July 22, 2005, 02:57:28 AM »

The angle of the trigger and hammer sear surfaces do not have anything to
do with your creepy trigger. You DO NOT want to change the angles
on these two parts.

Triggers are one thing that are best left to a smith, exp on most cap and ball
pistols because of the quality (or lack of) of the metal that is used on most
makes. If you stone them you will probably have to reharden them also.

The sear engagement can be reduced if it is excessive. But you still want
plenty of engagement so that you do not have a dangerous gun.

unspellable · « **Reply #2 on:** July 22, 2005, 05:18:39 AM »

Looking at the leverage, pivot points, etc. on this cap & ball revolver it's obvious that the creep (Meaning the distance the trigger moves before it breaks.) must be about 1.5 times the sear engagement.

It has been suggested that I put a shim on the hammer to prevent full engagement of the sear. This has the advantage of being reversible, one can remove the shim if it is held by an adhesive that can be dissolved in a suitable solvent. I may try this.

If I thin the sear without modifying the engagement surface (i.e. not changing the angles.) the surface hardening should be unaffected.

How is creep avoided in a quality trigger set up, say on my S&W? The creep is undetectable. The qeometry must be very different.

Keith L · « **Reply #3 on:** July 22, 2005, 01:10:23 PM »

I have improved triggers on a bunch of black powder replica guns and the quality range is all over the park. Sometimes two guns of the same model look quite different on the inside.

I don't know the proper term, but the point on the trigger that fits the notch in the hammer making up the sear is frequently quite broad, and sometimes even hook shaped. I polish that part while keeping what seems to be the appropriate angle. I also try to make the engagement the entire width of the mating parts. I frequently re-assemble to gage my progress. And KSR is right: you will have to re-harden the part when done. I case harden the part after stoning it using one of the case hardening products and a torch.

This is a job that requires lots of patience. Many kitchen table smiths give up because of how slow you need to work, and how often you need to assemble the gun, check the trigger, take it appart and stone a little more. When I get frustrated I put it away and come back later.

Good luck

gunnut69 · « **Reply #4 on:** July 22, 2005, 05:20:13 PM »

The three major components of a trigger pull are-weight of pull, creep, and over travel. One might also include take up.. Creep is mainly a factor of the condition of and amount of engagement of the sear surfaces. Polishing the cap and ball revolvers such as yours is an easy job but a time consuming one. Care must be taken to not alter the angle of the sears mating surfaces. One can create an angle that requires the hammer be pushed to the rear as the sear is moved. This adds to the trigger pull, as the mainspring tension must also be overcome. Generally a null angle is prefered. The surfaces move nearly paralell to one another.. and are smoothly polished. If the surfaces are square to one another and there's little wobble in the two parts a small ledge can support a trigger quite well. Usually the metal on the C&B colt clones will require case hardening after stoning for long life and safety.. To answer your other question the S&W revolvers sears have tiny engagement surfaces...well polished. That's why the triggers are creep free. This is one of the places quality will show, the other is longevity..

unspellable · « **Reply #5 on:** July 25, 2005, 01:53:28 AM »

Well, I took the sideplate off of a S&W and as I suspected, the geometry is very different. It's not just a matter of quality. It's a quantum leap in improved geometry.

In the Colt style cap & ball it's obvious the creep must be proportional to the sear engagement and that cannot be altered. All one can do is reduce the engagement.

Polishing the mating surfaces may smooth out the creep but it will do nothing to reduce it. It is the mating surfaces where surface hardening counts.

Reducing the width of the notch will reduce engagement but will not affect the surface hardening on the engaged surfaces.

I am coming to the conclusion that he simple fix here is adding a shim to the notch to reduce engagement. This has the advanatge of being reversible. It's becoming obvious that the creep can never be eliminated in this setup, only reduced.

Next question, is why no creep in my Rogers & Spencer replica? I'll have to look att he innards on that one.

gunnut69 · « **Reply #6 on:** July 25, 2005, 09:36:33 AM »

It's not quite true that you can limit the sear engagement with impunity. The metal that supports the sear surface must be capable of the added stress. The simplest fix is a light pollishing and limiting the engagement.