Double Set trigger adjustments

[tnlonghunter]

I'm about done with a build I started last November, but the triggers have an issue I'd like to try to correct. It's 2 separate things, but I'm pretty sure they're related. When testing the set triggers alone (without the lock), they set and release just right. However, when actually tripping the lock, the following takes place:

1. If firing unset, the front trigger is a little heavier than it should be. Somewhere around 5-6 pounds if I had to guess. It's crisp, with practically no take-up. If like it a little lighter.

2. When firing set, the set trigger sets fine (maybe a touch heavy). However, the front trigger seems to have a 2-stage effect. First there is a minor click but no release. Then with a slight bit more pressure the trigger releases. Out of about 3-4 dozen test firing, the cock has stopped in the half-cock notch 2 times.

As to the geometry and location, the cross- point of the trigger bars is right under the sear bar of the lock. However, I wonder if the triggers are inlet too deep. There is almost no play between the front trigger and the sear bar.

I plan on testing this with a couple of shims under the trigger plate to see if the greater distance between the triggers and sear bar improves things (the lock is currently disassembled for polishing or I would have done it already).

So here are my 2 questions:

1. What other possibilities could explain why the triggers are fine alone but get ornery with the lock in place?

2. If in fact there just need to be more space between the trigger bars and sear bar, can I safely file down the top of the trigger bars? Would there be any potential pitfalls?

 

[ohio ramrod]

I like a little space between the bars and sear. But remember files for putting on steel are really hard to find.I would look for any wood interfering with the triggers and the fly.As for the triggers being hard to fire unset I would consider polishing the contact surfaces.and check the angle of the tumbler notch with the sear. You want an exact 90 degrees. Less than 90 you are fighting the mainspring, over 90 it will want to "push off" and not hold.

 

[Grenadier1758]

I'm about done with a build I started last November, but the triggers have an issue I'd like to try to correct. It's 2 separate things, but I'm pretty sure they're related. When testing the set triggers alone (without the lock), they set and release just right. However, when actually tripping the lock, the following takes place:

...

2. When firing set, the set trigger sets fine (maybe a touch heavy). However, the front trigger seems to have a 2-stage effect. First there is a minor click but no release. Then with a slight bit more pressure the trigger releases. Out of about 3-4 dozen test firing, the cock has stopped in the half-cock notch 2 times.

...

I plan on testing this with a couple of shims under the trigger plate to see if the greater distance between the triggers and sear bar improves things (the lock is currently disassembled for polishing or I would have done it already).

So here are my 2 questions:

1. What other possibilities could explain why the triggers are fine alone but get ornery with the lock in place?

2. If in fact there just need to be more space between the trigger bars and sear bar, can I safely file down the top of the trigger bars? Would there be any potential pitfalls?

The issue with the triggers, especially with the sear stopping in the half cock notch, is a lock issue. The fly is not free to move in the recess in the tumbler and is not covering the half cock notch when the hammer is falling. Look for something binding in the bridle on the axle of the tumbler. Look to see if the bridle is a clearance fit with the tumbler and the sear lever. Does the fly move freely in the tumbler? I have a lock that the bridle screws will loosen and the fly moves to the side of the sear lever and the sear falls into the half cock notch. You need to be looking for something that isn't just quite right. Something that is rubbing. Are the lock bolts to tight?

It would be better to use shims to lower the triggers in the lock mortise. As has been observed, there's no file that can restore metal.

 

[dave_person]

Hi,
This may explain a lot.
https://www.muzzleloadingforum.com/threads/inletting-for-a-double-set-trigger.132580/#post-1847038
dave

 

[tnlonghunter]

Thanks for all of that, Dave, Grenadier, and Ohio. All makes mechanical sense in my head once I read it. I'll take a look at all of these issues and avoid filing anything if at all possible.

 

[necchi]

What trigger do you have?
Clean and Lube the trigger, use a basic light gun oil and keep it fresh. new triggers are not properly lubed for actual use as received from the supplier.
Shipping lubes, old dry oil and gunk can cause a significant drag in the components of this simple mechanical device.

What other possibilities could explain why the triggers are fine alone but get ornery with the lock in place?

Tighten the trigger main spring screw, the rear trigger "set" should be a hard pull, more than just a heavy feel. It's the main spring that drives the rear cam into the lock sear when released.
And of course adjust the break point screw.
In-letting too deep has some easy test's to find out it's the problem, basically simple shimming to experiment with, and shim's or re-bedding as a fix.
Just be sure the trigger has good lube and a proper tune before getting too far into a misplacement issue.

 

[tnlonghunter]

Thanks for the guidance. A couple of thin washers under the back end of the trigger plate did the trick. Just needed a touch of space.