Trigger clicks before firing

[HighUintas]

I've got a Davis set trigger and chambers late ketland lock. When I go to full cock and pull the main trigger unset, there first is a slight movement of the trigger and a click, then pull again and the lock will fire. It's almost like a two stage trigger. The lock itself doesn't do this when cocking/firing not installed.

I had solder an extension onto the trigger bar because they were too short. This could be related but don't know yet.

I'm going to put some black on the trigger bar this evening and see if I can tell if this is coming from the sear bar and trigger bar interaction.... But it seems unlikely because I polished the surfaces smooth.

Are there any ideas on what might be the cause so I can try other troubleshooting steps as well?

[EC121]

Sounds like the back trigger bar isn't tripping the sear and the front trigger is doing it on the second pull.  Tighten the mainspring screw or inlet the triggers a little deeper.

[HighUintas]

Sounds like the back trigger bar isn't tripping the sear and the front trigger is doing it on the second pull.  Tighten the mainspring screw or inlet the triggers a little deeper.

This is without setting the trigger. If I set the trigger, it will function as it should with just a light touch on the main (front) trigger. NOT setting it first, the main trigger does the click with a miniscule movement, then fires with an additional pull. It's a light, crisp break too 

[EC121]

Might have a burr on the full cock notch or sear nose.  Did you polish the tops of the trigger bars  and put a touch grease on them ?  If nothing else works just pull quicker.   

[HighUintas]

Ha yes that's one way to do it. It functions just fine, but bothers me because it's not supposed to happen.

The trigger bar tops and sear bar is polished. I also checked the sear nose and tumbler notch engagement when polishing everything and it looks good to me.

I did a preliminary check just now to see if anything was binding. I loosened the tang bolts (long tang w 2 bolts) and held the trigger plate in firmly by hand while operating the cock and trigger. Voila!! No two stage trigger. I tightened the rear tang bolt fully and it still works. Loosened the rear and tightened the forward tang bolt fully and it went back to having that first click.

So, something is binding when tightening the forward tang bolt. The odd thing is that after it does the first click (before the second pull and firing) there is a tiny bit of play in the trigger as if it is not engaged with the sear bar. So I think that first click is the front trigger getting dislodged from the bound state it is in.

My guess is that the rear tip of the front trigger bar is getting caught on some wood when I tighten that tang bolt all the way.

[Bob Roller]

The triggers are not custom made and like other components for muzzle loaders they sometimes do not come out of the box ready to use.
Some of them are unusable when they arrive because of indifferent assembly by someone who has no idea as to proper function of what they are assembling.Take out of box and rebuild before using.a real recommendation
Bob Roller

[HighUintas]

Bob, yes I agree that all parts that are bought need to be worked over before using and this includes my lock. I went over my trigger assembly very thoroughly awhile back.  It is the culprit here.

I spent a few hours with marking color on the trigger, shaving off bits of wood and fiddling with the trigger itself.

I checked the lock again after being stumped. Even though the tumbler notch and sear nose looks great and usually operates smoothly, by very carefully tripping the sear bar by hand when holding the lock, I can get it to do the slight movement and click without the cock releasing. So there is something that needs to be improved between the sear nose and tumbler notch but I'm not sure what. It will probably make a trip to someone to have that and other things on the lock fixed.

[Daryl]

Sounds to me there is a step in the full cock notch. (just a guess? otherwise, stumped)

[Bob Roller]

Bob, yes I agree that all parts that are bought need to be worked over before using and this includes my lock. I went over my trigger assembly very thoroughly awhile back.  It is the culprit here.

I spent a few hours with marking color on the trigger, shaving off bits of wood and fiddling with the trigger itself.

I checked the lock again after being stumped. Even though the tumbler notch and sear nose looks great and usually operates smoothly, by very carefully tripping the sear bar by hand when holding the lock, I can get it to do the slight movement and click without the cock releasing. So there is something that needs to be improved between the sear nose and tumbler notch but I'm not sure what. It will probably make a trip to someone to have that and other things on the lock fixed.

OK.Take a close look at the screw the sear turns on.Some of them are fit like a broom handle in the garbage can.Ok  for broom but no good in a gun lock.
Bob Roller

[smylee grouch]

I think if you clean up the inlet and use transfer color you might find some wood interfering with the parts.

[Bob Roller]

Using  feeble mind to recall,when I had Leonard Meadows build me a Tn long rifle i deliberately put a small "scratch"across the area where the front and rear trigger engage and unless it was adjusted to where the slightest touch could fire it the "scratch" could be felt and the lock was very close to being fired.I think it was called "staging" and it worked for me.The Chambers Late Ketland is a good lock and I think their quality control is as good as mine was when I quit locks in 2019.I was fussy about the sear screw/sear fitting.The English styled Stantons had a rotating clearance of a .110 hole and a .1094 pin with no threads and that allows a shall full cock position.
Bob Roller

[HighUintas]

Daryl, I think you may be right. When at full cock, there is the tiniest bit of play in the front trigger. After the click, there is noticeably more play in the front trigger due to the sear bar moving a tiny amount on the notch.

Bob, I'll have to see if I can get a picture of it later, but I think this lock may have been a skimpy QC check. There's a good sized gap between the sides of the sear screw hole and the lock plate and screw head. The sear can move side to side on the sear screw. If I remember from the last time I had it apart, there was a lot of clearance between the sear screw shaft and sear screw hole. The tumbler and bridle are also not square to each other or square to the lock plate :/

[Bob Roller]

That is completely  out of line with the known quality control associated with the Chambers locks and I am surprised it got out of their shop
Have you contacted Chambers? I know them and they would not want this lock to be around.
Bob Roller

[HighUintas]

Not yet. I had polished it and cut the tit off the rear of the plate to make it round and inletted it before I noticed because the internals inspection was last. I learned my lesson! I'll probably give them a call to see what would need to be done to get everything square.

[Bob Roller]

The LOCK is the mechanism,not the plate. Call them.I doubt if altering the shape of the plate can bring on the conditions you describe.
Bob Roller