Percussion locktuning

[crockett]

I have a Deer Creek Rifle kit. It looks like the parts are identical to CVA. The percussion lock needs to be tuned up and the set up is a little different. Most sears seem to have a bushing to wear against the lock plate. My lock has a small washer, the sear has no bushing. The stud on the bridle also seems to be too long, so that the bridle doesn't fit flat. The bridle also extends farther back than normal and includes covering the screw for the sear spring. Due to the long bridle stud, the bridle isn't really holding everything in line and the sear is sort of angled with the back closer to the lock plate and the front out a little from the tumbler's notch. Oh Joy!
In any event this is what is on my mind. Shouldn't the width of the tumbler equal the width of the sear/washer? That said, shouldn't the stud on the bridle be reduced so that the bridle is tight against both the tumbler and sear so that everything is held in line? Why bother trying to get a good sear/tumbler engagement until this problem is solved?
Here is what I intend to do. 1. Use dial calipers to measure the width of tumbler versus the width of the sear/washer. If they are off I will change the washer to get equal widths. I will then measure the stud from its inside base and file it down until it also equals the tumbler width. Then when the bridle is screwed down all should be held in line.
The fly on this lock is on the inside, against the lock plate. It is just a little wider than the sear's washer.
If it looks like I am headed down the wrong road, please let me know. Thanks for any help/advise. :hmm:

 

[Terry Zboril]

" Shouldn't the width of the tumbler equal the width of the sear/washer? That said, shouldn't the stud on the bridle be reduced so that the bridle is tight against both the tumbler and sear so that everything is held in line?"

Crockett,
The bridle should NOT be held "tight" to the sear or tumbler, in percussion or flint. There should be a few thousanths clearance on both .

The tumbler holes in both lockplate and bridle should be a close fit to keep the tumbler in line. The sear hole and sear screw should be a close fit to keep the sear in line.

The sear and tumbler should move freely beneath the bridle.

If the bridle is "tight" against these moving parts you are just asking for trouble, no matter how many bearings or washers are involved, :imo:
Regards,
Terry

 

[crockett]

thanks

 

Sounds like the holes in the bridle are wollowed out, allowing the flex in the parts. In fact, it sounds like the bridle does not fit this lock and may be from another application. It's the diameter of the axles pins of the sear and tumbler in relationship to the holes in the bridle, and lockplate, you need to address.

 

[crockett]

Ghost: I took off the bridle and put everything back on without the bridle and lock works okay. The bridle is screwing things up and I agree, it was poor machining from the start. Anyhow I did a bit here and there and it's about as good as my other locks that don't have bridles.
The other two locks work pretty good, even though they are inexpensive and I guess that raises an interesting point, you are probably better off with a good lock with no bridle than a poor lock with a bridle. This latest gun that I am building, I wanted set triggers and a lock with a bridle, they just had to be better. Truth is, I'm not all that impressed. You can take a regular trigger and get about as good a pull as with the set trigger. Until you are ready to shoot the gun ought to be on half cock anyhow. Same thing with the bridle, if the lock is machined properly the bridle is better but just having a bridle for the sake of appearance doesn't make sense.
In any event I bought the kit as a "learning experience". The lock works okay it's just that I wanted something as smooth as silk.
Along the lines of percussion locks and tuning, what's the purpose of the fly? It seems to me they are needed on a set trigger but not otherwise. Is it because a human pulling the trigger can't release the trigger fast enough for the hammer to catch in the half cock notch but a set trigger instantly has a loose trigger, hence the need for a fly?

 

You have it about figured out crockett, on both counts. Unbridled locks were the standard for the first 100 years of flintlock development. Unbridled locks were the standard for most trade guns (they were actually considered pieces of crap in their day) and trade rifles long after that. They are still the standard on our cheap guns of today.

However, do not discount the well made lock with a well fit bridle for smooth operstion. I have never built a percussion lock from kit, but I have built numerous flint locks from kits and from scratch. A well made lock is a wounderous thing and one will never be satisfied with a piece of Pedersoli or Spanish crap from their first shot with a good Siler or Davis.