What I do to tune any lock that I use in building a rifle. I am not lock maker and I first want to say a big thank you to all our lock makers out there. This is not a post to complain about any lock nor do I want this to turn into a post for others to complain about any locks. In making a reply to coryjoe's post he asked the question about what makes a lock right. So I thought I would post a few things that I do and I hope others may post some suggestions also to make a lock function smoothly and help give a nice light trigger pull.
The first thing I do on a flintlock is to put a good flint in and cycle the lock several times to see how the lock sparks and does the cock, flint and frizzen line up well.
If the lock cycles well then I look at the internals and the inside of the lock plate for any signs of the mainspring rubbing the lock plate. I also look at the tumbler and the sear arm to see if they are rubbing. I make a note of anything that is leaving any mark on the lock plate. I stone these until they leave no more marks on the plate.
I totally disassemble the lock. I use two spring vises, one for the main sping and one for the frizzen spring. Good sprinig vises are well worth their money. Good fitting screw drivers are another absolute must for this job.
Once I have the lock dissasembled I then drag out my polishing stones and work over every part that touches another part and all bearing surfaces. I have various shapes and courseness of stones for this job.
After stoning I break out my PC Dremmel and felt tips and my polishing rouge and I polish all the stoned surfaces to a mirror polish.
Using magnification I look at the full cock notch to ensure that is is nice and square and has no burrs that the nose of the sear might get hung up on. This is a critiacal area of any lock and great care has to be taken here to ensure proper function. To much polishing or rework of the full cock notch can make for a unreliable and possibly unsafe lock.
I polish the tumbler bridel pin by chucking up the tumbler in my hand drill on slow, use 400 grit sandpaper backed by a file and then polish. I do the same thing for the tubler shoulder that goes through the lock plate. I also polish the hole in the lock plate.
I then go the sear and look at the nose of the sear that engages the full cock notch to make sure it is square and that it has no burrs and I polish it to a mirror finish.
I then assemble the lock and cycle it severl times. While doing this I am feeling the action and trying to feel anything that is not working smoothly. If everything on the internals feels good then I will turn my attention to the frizzen and make sure that it's fit to the lock plate is not binding anywhere. I normally stone the mating surfaces and polish the foot of the frizzen and the surface of the frizzen spring that the foot rides on.
I also polish the polish the shank of the sear screw and the frizzen bridel screw and the hole in the frizzen for the screw. I have found that every little bit helps.
I polish the foot of the sear spring that rides on the sear.
I normally do not try to alter any of springs. I have never had any problems except for a couple of weak sear springs and once these were replaced with new ones there was no more problems.
This whole process takes me about 8 hours but it makes such a difference in the opperation of the lock I feel it is time well spent.
