How does a set trigger work?

[jtmattison]

Let me give a little background on this question.
I recently took my GPR trigger out to work on it because my set trigger is terribly stiff.
While operating the trigger off of the rifle I saw that when the set trigger is pulled it engages a notch in the main trigger. Then when the main trigger is pulled, the arm, striker, whatever it's called that engages the sear bar pops up with spring loaded force.
When the set trigger is not used, the main trigger is pulled and the sear bar is engaged directly and operated as you pull the trigger.
It seems when you use the set trigger, the main trigger acts like a hammer and pops up hitting the sear bar.
Does this make sense?
Maybe someone can shed some light on this for me.
I'm going :youcrazy: trying to figure it out.

HD

 

[boar]

Sounds like you got it figured out. The little screw adjust's how much notch you have on the front trigger, I don't set mine real light. I seen some target shooters that a very light touch sets them off. I have stoned them smooth. Dilly

 

[Titus]

yep, I reckon youve got it covered there. not much more to it.

 

[lanedh]

Hi Dawg--

Have you discovered why the trigger mechanism is so stiff?

I find my GPR trigger is a bit stiff too, but I haven't replaced the engagement screw as yet to provide a lighter let-off pressure. (went to the local hardware store and found the last two M2.5 screws, 8 mm and 12 mm long; one of them is bound to work).

Check the inletted area around the trigger to see if any wood is bearing on the moving parts, then have a close look at the trigger parts to see if there is any obvious interference causing binding. Maybe a little medium weight lube oil will help too.

Just some random thoughts.

BJ

 

[2172]

The sear spring is a coil spring, in a little tube...if you take a turn off that spring, you can lighten the trigger pull, Hank

 

[jtmattison]

The set trigger is the stiff one. The spring on it is very stiff. Adjusting the set screw only shortens the pull of the main trigger. There is also a screw under the set trigger spring that you can adjust but it doesn't make the pull lighter, it just shortens the distance you have to pull the set trigger. I'm trying to figure out how to lighten the set trigger spring.

I might order a Davis trigger for it.

HD

 

[sparsons]

Don't know if my Thompson Hawken is like your rifle. I have an adjustment (allen wrench) that will makes the set trigger stiffer or weaker. If it gets to loose it will not engage the main trigger. That happened last time out. I had to tighten it up for it to engage. I got home and experimented some and found the tighter the allen wrench adjustment the stiffer the pull on the set trigger. I have mine set to my liking but packed the proper allen wrench just in case I might need it again. :hatsoff:

 

[silverfox]

Rebel if I got your drift right you are saying that to pull the set trigger it is heavy. You have the working right on a set trigger. Now the probable reason the trigger is hard is it is controlled by a heavy spring that controls the pop up bar that strikes your sear bar. If you get it to light the bar won't strike the sear with enough force to release the hammer. I have one that almost takes 2 fingers to set the trigger but it never fails to drop the hammer when you pull the trigger. I had it set lighter once and it wouldn't trip the sear. Not nice to pull the trigger hear a snap and the hammer doesn't fall.
Don't set it to light thats just part of the beast. It takes pounds to set the trigger and Oz. to set it off.
Fox :thumbsup:

 

[jtmattison]

Rebel if I got your drift right you are saying that to pull the set trigger it is heavy. You have the working right on a set trigger. Now the probable reason the trigger is hard is it is controlled by a heavy spring that controls the pop up bar that strikes your sear bar. If you get it to light the bar won't strike the sear with enough force to release the hammer. I have one that almost takes 2 fingers to set the trigger but it never fails to drop the hammer when you pull the trigger. I had it set lighter once and it wouldn't trip the sear. Not nice to pull the trigger hear a snap and the hammer doesn't fall.
Don't set it to light thats just part of the beast. It takes pounds to set the trigger and Oz. to set it off.
Fox :thumbsup:

You hit the nail right on the head.
I adjusted the screw on the set trigger spring and then the main trigger would click but no hammer fall. Pulling the main trigger farther made the hammer fall. I put everything back the way it was and all works fine. The set trigger is just a lot harder to pull than on my other GPR. I'll live with it.

HD

 

[Rebel]

Silerfox, Not sure how yu got me into this conversation, cuz i haven't replied to it yet. :grin:

 

[Zonie]

Huntin Dawg:
The only thing you said about how a set trigger works that I don't agree with is when you said
"It seems when you use the set trigger, the main trigger acts like a hammer and pops up hitting the sear bar...."
The thing that pops up and hits the sear bar is the top of the rear set trigger when it is released by the front trigger.

As for the heavy rear set spring, as I mentioned above, my rifle is the same as yours.

The only thing that can be done to lighten this is to reduce the thickness of that rear spring.
I did this to mine and it improved it quite a bit, but it is still a heavy pull.

If you decide to do this, you will have to grind or file its thickness down.
This spring is so hard that you should plan on ruining a good file and I don't think a cheap file will cut it.
Make all file marks or grind marks in the long direction of the spring. NEVER make a mark across the narrow part of the spring. If you do, it will break for sure.

As you are thinning, keep in mind that a flat springs pressure works as the cube of it's thickness. You don't have to do any calculating, but if you reduce the thickness from let us say .07 to .05 (a 28 percent reduction) the springs pressure will be reduced over 36 percent.

As you found, if the spring pressure is too light, it won't work so if you decide to thin the spring, be prepared to buy a replacement from Lyman.

zonie

 

[jtmattison]

Huntin Dawg:
The only thing you said about how a set trigger works that I don't agree with is when you said
"It seems when you use the set trigger, the main trigger acts like a hammer and pops up hitting the sear bar...."
The thing that pops up and hits the sear bar is the top of the rear set trigger when it is released by the front trigger.

I'm glad you clarified that. I was wondering if that was how it worked.
Now tell me this...When you pull just the main trigger without setting the set trigger you are engaging the sear bar directly and your pull is what sets it off, right?
When you use the set trigger as you said it pops up and strikes the sear bar like a hammer setting off the lock, right?

I think I've got it now.

I don't plan on reducing the spring. I think now that I know how it works I'll leave well enough alone. Or I'll buy a Davis trigger.

HD

 

[silverfox]

Must of been the old age thing. Sorry about that.
Fox :thumbsup:

 

[Zonie]

H.D.: You've got it! :grin:
Now don't let you wife know, or she will either want it, or she'll tell you that you can't have it. :rotf:
zonie

 

[Mad Professor]

I've put the Davis "deerstalker" triggers into some of my TCs, they work great and are nice and light. 5 minutes with a wood chisel and they drop right in to TC stocks.

Not that the TC triggers were really bad, they are much nicer than my Lyman set triggers. I'm contemplating putting one of the extra TC triggers into a Lyman if I don't put a Davis into it.

Anyway, if you can get a used TC trigger assy cheap that is an option. If you have to go new the cost of the Davis is the same as a new TC.