Boat anchor material!

[Sun City]

That’s not the case with the L&R locks I own. The hole is in the fly and the pin is in the tumbler. L&R even specifically mentions a couple of times in their instructions (something to read when all else fails) how to correctly install the fly. Here is a photograph I provided someone for reference quite some time ago when they were having a similar problem with an L&R lock. Note the hole in the fly and the pin in the tumbler.
View attachment 164029

Then you likely don’t have an L&R lock, so the issue must be something else. But IF you have an L&R lock/boat anchor, the fly in your photograph is backwards.
View attachment 164030

It's a Davis lock

 

[Alby]

it may be that the sear is catching on the flat rear edge of the fly when the set trigger is used. It may need filing or a new fly before it damages the nose of the sear. I hope you find the problem and is an easy fix.

 

[Grenadier1758]

If the fly is assbackards......WHY will the lock function correctly out of the rifle??

This isn't an easy question to answer. A lot depends on how the lock is operated when out of the rifle. Are you lifting the sear enough to clear the half cock notch. If you hold the sear off the tumbler for this test, then the lock will function correctly out of the rifle. When I look at lock function when the lock is out of the rifle, I hold the hammer and lift the sear enough to clear the full cock notch. I verify that the sear nose is riding on the tumbler and lower the hammer slowly allowing the sear to follow the rotating tumbler to see if the fly will lift the nose of the sear over the half cock notch. I see an edge on the fly that looks as if it will catch and stop the sear from being lifted over the half cock notch.

Have you tried to make contact with the R. E. Davis company to see if they will inspect your lock? I think that may be your next step.

http://redaviscompany.com/index.html

 

[Dusty_Traveler]

I would loosen off on the sear screw a quarter turn at a time, and see if that helps anything. I have an original rifle with a Goulcher percussion lock, and if the sear screw is too snug, it will land in the half cock notch every time.

 

[colimr]

#1 does the lock function out of the gun can you manually half cock and it holds full cock and it holds trip it and the hammer falls all the way down all done holding it in your hand. If this functions correctly your problem is your trigger. or wood obstruction or over tightening the lock retaining bolt
#2 leave the lock installed remove the trigger repeat #1 trip the hammer using something like a popsicle stick thru the space where the trigger sits .to trip the sear if the lock functions properly again in all steps it is NOT your lock it is NOT any wood interference it is your trigger or lock retaining bolt is too tight
Either of these steps only take 2 minuets if the lock fails any steps in #1 the issue is in your lock if your lock passes #1 but fails #2 there is an obstruction .All these checks done without the trigger spend the time you will be surprised. In #1 you can actually watch each part of the lock the fly, the bridle ,the sear function very interesting just don't ger your fingers near the pan when the hammer falls I use a folded peice of leather to cushion the hammer/pan pinch your finger you will to please let us know your results
NOTE failure in #2 could also be overnighting the bolt that hold the lock that bolt can hit the hammer stopping it from falling this is an easy diagnosis just leave the bolt a little loose and recheck hammer another easy and fast check and can be done with trigger installed or not

 

[M. De Land]

I've got a flintlock that is driving me nutty....nuttier! I cannot get the cock to strike full forward as it stops at the half cock position; no matter whether the Davis set trigger is set prior to fully cocking or being set afterward! Basically right now its boat anchor material since I can't get it to fire! I have no interference from wood and I've set the tension on the triggers several different ways in trying to find what works! It seems that the rear trigger which is the 'set trigger' pops up and interferes with the sear bar and prevents following through to full forward. Lock seems to be OK and there is a fly in the lock. I'm totally stumped!

IMG_3537 by Sharps Man, on Flickr

You probably need to increase the spring (large one in the back) tension on the kicking trigger sear. I just repaired a custom built Hawken that had the same problem. What most likely is the trouble is the sear leg is a bit short so the kicking trigger lever has to give it a bit more of a whack to clear the half cock notch in the lock .
The other possible fix is to reduce the lock sear spring tension a bit.

 

[Snooterpup]

If the lock works off the gun, try this:
Reinstall the lock. Remove the trigger assembly completely. Cock the lock and try to trip the sear using gentle pressure with a popsicle stick or screwdriver. If it works like that, shim the trigger assembly with card stock. It’s possible the trigger bar it too high or too tight against the sear. I’ve seen this before due to minute changes in the stock over time.

 

[Grenadier1758]

I am beginning to like @M. De Land's speculation that the sear spring is too strong and applying too much force on the sear, holding the nose of the sear tight against the tumbler. I also think @Dusty_Traveler's suggestion to loosen the screw in the bridle through the sear has merit as the friction between the bridle and the sear may be too much to allow the sear to be lifted over the fly and the half cock notch. Look for rubbing of the sear on the lock plate.

The solution will be simple, but hard to diagnose from a keyboard.

 

[SDSmlf]

It's a Davis lock

Something with the fly in your photograph doesn’t look correct, though it could just be an optical illusion from lighting and shadows. The trailing edge of the fly needs to be flush or proud of the half cock notch in the tumbler for it to work properly with a set trigger. The tip of your fly appears to be below the notch, but again, it could just be the lighting.

For reference, I took photographs of some of the locks that are in my shop right now. Notice the tip of the fly position relative to the half cock notch.

 

[M. De Land]

IMG_3540 by Sharps Man, on Flickr

IMG_3539 by Sharps Man, on Flickr

The set trigger I repaired after trying a number of things looks exactly like the one in your picture . After tightening the kick trigger spring it worked every time even after setting it out in the cold for several hours. The down side was it made cocking the set trigger very hard with the tight curl, low leverage, set trigger profile.
In retrospect I think I should have lightened the sear spring in the lock and perhaps as suggested checked to see if the bridle screw was to tight. This is where bridle plate pins come into play and pay for they're keep.

 

[Grenadier1758]

Happy to hear that @Sun City has found a solution.

 

[Sun City]

I honked the main trigger spring down as you advised and prior to that put a light touch of 3-1 oil to the lock and it works like a champ! As you advised makes setting the trigger a bit tough but I can live with that! Thanks!!

 

[Horse]

I honked the main trigger spring down as you advised and prior to that put a light touch of 3-1 oil to the lock and it works like a champ! As you advised makes setting the trigger a bit tough but I can live with that! Thanks!!

Yeah but now you gotta buy a boat anchor

 

[Sun City]

Yeah but now you gotta buy a boat anchor

Yep! LOL LOL!

 

[deerstalkert]

off thread but kinda on thread.
where can a guy get a fly for a siler lock besides DGW? the one in my current/stalled pistol build went walkabout.

 

[PathfinderNC]

Good Detective work

 

[Grenadier1758]

You should be able to get a fly for a Siler lock from Jim Chambers, who makes them.

 

[deerstalkert]

thanks Grenadier1758.
i dragged my sad self out and made one after posting. got to feeling ashamed for wanting to take the easy way out.
actually all replacements i have seen available are "as cast". working as cast parts to me is on par with going to a proctologist.

 

[Larry (Omaha)]

Imo replace the front trigger .The notch that holds the rear trigger is worn

With all respect to you. How does a warn notch cause the sear to fall into half cock? The trigger is tripping the sear, and that is its' function. Please explain the mechanics effect of a worn trigger notch on the sear.
Larry

 

[colimr]

spring tension holds the front trigger in contact with the rear trigger thru the male point on the rear trigger bar being captured in the female notch in the front trigger bar the rear trigger being released under spring pressure after being released from the front trigger is what contacts the sear. I misinterpreted the post and thought the rear trigger was not filly tripping th e sear and was catching the sear. If you read the op last post the trigger was indeed the issue and NOT any parts in the lock or any wood obstruction as so many posted wit spring grinding ,fly ,or bridle switching . the op ended having rear spring tension issues I was closer then any on but still wrong I belive post #30 had the trigger solution .Diagnosis is tough with only picture