Author Topic: double set triggers (again) Found the problem Happy Ending! (Read 2471 times)

Dowrat · « **on:** October 02, 2021, 12:18:03 AM »

I have a rifle with a Deluxe Large Chambers flintlock that I'm putting a Davis small #4 double set, double phase, trigger in. I've been filing down the trigger bars. The lock now clicks solidly into the half and full cock notches. I can now set the trigger in the half and full cock positions, but when I trip the set trigger (front) the hammer catches at half cock. What's going on?

Yes, I have used the search and read up on adjusting triggers, but still don't know what's going on.

Thanks in advance for any help with my problem.

Darryl

martin9 · « **Reply #1 on:** October 02, 2021, 12:48:07 AM »

I'd take the lock out and make sure the fly is still in the tumbler. If so I'd dab the internals with inletting black and see if the lock is rubbing anywhere inside the mortice.

J. Talbert · « **Reply #2 on:** October 02, 2021, 12:48:26 AM »

The problem is more likely with the lock (specifically the fly) rather than the triggers. The fly is intended to prevent this very occurrence. Make sure that the fly is operating properly when the lock is out of the gun, and verify that there is no interference with its proper function from the wood when the lock is installed in the gun.

Good luck,
Jeff

Shopdog · « **Reply #3 on:** October 02, 2021, 12:56:42 AM »

First I aint the expert but having just run into same issue I feel like i might offer some help - in my case was replacing a Davis flinter with its percussion twin - Davis double set trigger. All geometry seemed the same BUT kept hanging up at half cock once lock bolt installed and all buttoned up. Reason was sear’s “tail” was ever so slightly longer than original lock and was binding just enough but only once lock was installed with lock bolt tightened. Rather than relieve more wood from stock I ground off a tiny bit of the tail.
Two other things I’ve done to myself on past builds that resulted in a similar issue - forgot to install the fly and second - tightened down too tight on bridle and/or sear screws = binding.
I would defer however to more experienced builders and see what advice they have.

Dowrat · « **Reply #4 on:** October 02, 2021, 01:48:02 AM »

Thanks for your suggestions.

The fly is working well and, when bolted in, the lock fires perfectly by pushing a screwdriver in the trigger hole. The lock will also fire with a hard pull on the front trigger. Even with a screwdriver this lock seems to be harder to trip than other Chambers locks I've used.

Could the rear trigger blade be too tall and be riding on the sear after tripping it? Maybe I need to file more off the rear blade?

Daryl · « **Reply #5 on:** October 02, 2021, 02:20:46 AM »

If the triggers sets both at 1/2 cock and full cock, I'd say the trigger levers are good to go, no binding.
The problem is elsewhere. imho The fly is suspect.

flinchrocket · « **Reply #6 on:** October 02, 2021, 02:50:47 AM »

Is your front trigger hitting wood somewhere? Why does it pull so hard?

Dowrat · « **Reply #7 on:** October 02, 2021, 03:42:02 AM »

Inletting black shows me that the triggers aren't touching anything. I wish I knew why this lock is so hard to fire. I'm putting set triggers in this rifle because the single trigger I had in it was so hard to pull that I couldn't shoot it accurately, even after narrowing the sear spring to lighten it up. It takes a hard push with a screwdriver in the trigger hole to set this thing off. Sear screw is not too tight either.

I've built eight flintlocks and never had this problem. (I've had lots of other problems though.) Any help would be appreciated.

flinchrocket · « **Reply #8 on:** October 02, 2021, 04:17:26 AM »

If you have the lock out is it hard to push the sear to fire against your hand ?

Clint · « **Reply #9 on:** October 02, 2021, 04:31:32 AM »

If the fly is working and the triggers are okay , the sear would be the place to look.Remove the sear spring and see if the sear is bound. If the sear binds, the sear screw is probably too short. You could file a little thickness off of the outside of the bridle or get a longer screw. If the sear swings smoothly, put the spring back and see how the lock tripps with thumb pressure. It could be that the full cock notch is slightly rough or even undercut. If the tumbler needs to be altered, the best way to alter it is by honeing the notch. An effective way to hone the notch angle is with a steel bar that is ground to a sharp ninety degree edge coated with valve grinding grit. If you go that route, get fine grinding compound and use optical magnification to moniter your progress. Be prepared to assemble and disassemble the lock a dozen times or so and go slow. If you ever decide to build a lock from scratch you will assemble the lock a hundred times, and it goes pretty quickly. lastly look in the lock mortice. The most elusive place for a sear to fetch up is at the bottom of the mortice where the sear moves down from the notches.

Dave R · « **Reply #10 on:** October 02, 2021, 04:00:36 PM »

Is it possible that the lock sear pivot screw is too tight? Tighten it snug and back it off 1/4 turn or so and retry.
Also have you lubed the lock?

Dowrat · « **Reply #11 on:** October 02, 2021, 06:50:27 PM »

Okay. I really appreciate everyone's input. There is a lot of knowledge on this forum. I worked on this rifle this morning. First I honed the trigger bars smooth.

Removed the sear spring. Sear swings freely. It had a slight bur where the trigger bars hit. I honed it smooth.

The sear point that catches in the tumbler notch had a slight bur. Honed it smooth. Sear is not touching any wood.

Tumbler notches look okay.

Checked fly and lightly lubed it.

Lightly lubed the mainspring at the tumbler.

The lock works in my hand.

The hammer will lock safely in the half and full cocked positions. Not touching any wood. It will fire reliably with the front trigger (hard trigger pull). I can set the trigger at half cock and at the full cocked positions. Still...The hammer will catch at half cock every time when fired with the hair trigger (front trigger).

I'm completely stumped!

smylee grouch · « **Reply #12 on:** October 02, 2021, 07:08:37 PM »

Maybe posting a picture of inside of lock will help others to see if they can spot something wrong.

flinchrocket · « **Reply #13 on:** October 02, 2021, 08:21:05 PM »

It’s obvious that the sear nose is not maneuvering the fly to prevent catching in the halfcock notch, which is the fly’s purpose. To get a better understanding of how that works,remove the mainspring with everything else in place,then slowly operate the lock while observing how the nose of the sear pushes the fly forward to block the notch in the tumbler. Then, when you pull the cock back it will drag the fly rearward to allow access to the notch again. With that, when you install the lock in the gun something is rubbing somewhere to prevent the proper operation of the fly. Also, if the lock works out of the gun,but not in the gun that is almost proof it’s rubbing when you tighten the lock bolts. These places can be hard to find sometimes. Put inletting black on everything ( this is where candle smoke works good because it’s thin.) operate the lock and remove it carefully to see where it was rubbed off the lock.

Dowrat · « **Reply #14 on:** October 03, 2021, 12:03:09 AM »

Found the problem!

Flinchrocket gets a gold star for his suggestion to remove the mainspring and manually operate the lock to see what the fly is doing. Doing this showed that, no matter how I tighten it down, the bridal is too far from the tumbler. ( possibly bent or doesn't fit right?) This allows the fly to move out too far from the notch on the tumbler. (possibly bent or something?) A hard pull on the front trigger held the sear out passed the half cock notch and allowed the lock to fire. But, the slap of the set trigger didn't hold the sear out and allowed it to catch in the half cock notch because the fly was too far out.

Posting pictures of lock in half cock and full cock. Notice the gap between the bridal and tumbler and the fly out too far.

EC121 · « **Reply #15 on:** October 03, 2021, 12:19:31 AM »

The bridle foot is probably crooked under the top screw. That will kick out the bridle at the sear screw. See if the foot of the bridle is square with the lock plate. It might have to be filed square.

smylee grouch · « **Reply #16 on:** October 03, 2021, 12:36:37 AM »

Is it possible that you have the wrong screws in the bridle thus not allowing it to be screwed down on to the plate ?

Dowrat · « **Reply #17 on:** October 03, 2021, 02:02:38 AM »

This is the way the lock came to me new. I haven't changed anything.

flinchrocket · « **Reply #18 on:** October 03, 2021, 02:06:24 AM »

If you don’t feel comfortable with repairing it just call Chambers and I’m sure they would be happy to take care of you.

Dowrat · « **Reply #19 on:** October 03, 2021, 02:12:27 AM »

I'll call Jim Chambers on Monday. Of course I've had the lock apart more than once to inlet it into the stock. I could have screwed it up myself. I'll ask Chambers what I should do.

flinchrocket · « **Reply #20 on:** October 03, 2021, 02:56:27 AM »

You might take it apart and carefully reassemble now that you know the problem.

P.W.Berkuta · « **Reply #21 on:** October 03, 2021, 08:56:43 PM »

That is a poorly assembled lock - either the bridle screw holes are drilled & tapped at an angle. lower bridle screw is too short and canting the bridle when tightening, the tumbler pivot hole in bridle & plate are oversized or the bridle is bent -- maybe a combination of all four

. Poor quality control for sure.

JTR · « **Reply #22 on:** October 04, 2021, 02:41:03 AM »

Is that metal galled/scored on the tumbler, where the sear rides against it?
Or is that just crud or something?

Birddog6 · « **Reply #23 on:** October 08, 2021, 12:59:03 PM »

Bridle is not snug & is not square, unless you loosened it to take photos.
Tumbler needs polished.
Appears to be no lubrication on the lock.

Birddog6 · « **Reply #24 on:** October 08, 2021, 01:07:07 PM »

The Trigger Pull on the locks is trigger design & positioning. Every Davis trigger I use
I have to rework them. Problem is have I not found any better, and just rework them
as part of the build. I make the blades on the trigger taller & angle them, then polish
them. End result is about a 2.5 to 3# pull on the front trigger & set trigger works
as it should.
When I first started building rifles everyone told me the 8-10# front trigger pull was the
way all of them are.

I'm think to my self, that is total BS. There is no way a front
trigger should be 8-10# pull. So I messed with them til i got them to work the way i think
is correctly.

News:

Author Topic: double set triggers (again) Found the problem Happy Ending! (Read 2471 times)

Birddog6

Birddog6