Percussion lock design

[tallPercshooter]

Always wondered about the merits of two kinds of percussion lock internals - one where the mainspring bears directly on the tumbler, and the other that uses a link and claw on the mainspring tip. That latter seems to add extra parts, small, thin parts at that. Whereas the direct bearing kind looks more robust and less to go wrong. I have both kinds, never had any trouble with either. Maybe the link style has a feature I am not aware of?

 

[Phil Coffins]

The link is a up-grade to a lock if done well, it improves the performance and longevity of the lock.

 

[M. De Land]

Always wondered about the merits of two kinds of percussion lock internals - one where the mainspring bears directly on the tumbler, and the other that uses a link and claw on the mainspring tip. That latter seems to add extra parts, small, thin parts at that. Whereas the direct bearing kind looks more robust and less to go wrong. I have both kinds, never had any trouble with either. Maybe the link style has a feature I am not aware of?

The link commonly referred to as a stirrup greatly aids lock efficiency enhancing main spring performance by reducing friction. It also extends life to the main spring and interfacing parts and almost never fails if properly installed.
It also smooths out lock function which aids longevity.

 

[wiscoaster]

I have locks with stirrups and locks without and have noticed no difference in functionality and/or performance, though that's over a very short time period, and I can't speak to longevity. I think it's mainly a case of you "work with what you've got."

 

[M. De Land]

I have locks with stirrups and locks without and have noticed no difference in functionality and/or performance, though that's over a very short time period, and I can't speak to longevity. I think it's mainly a case of you "work with what you've got."

It's the same deal with bridles, in lock evolution, the best locks use them !

 

[kyron4]

It's the same deal with bridles, in lock evolution, the best locks use them !

I'm curious, is the function of the bridle to give the hammer more support, as in a second bearing surface, or is it only there as part of the two/set trigger set up ? -Thanks

 

[M. De Land]

I'm curious, is the function of the bridle to give the hammer more support, as in a second bearing surface, or is it only there as part of the two/set trigger set up ? -ThBridle

 

[M. De Land]

Bridles are important to both Frizzen (flint locks) and hammer/ sear/fly function in both percussion and flint locks. They provide two position bearing function rather than single position bearings. This makes locks stronger, more efficient and last longer.

 

[Larry Akers]

In the evolution of the sidelock, the addition of the bridle and the stirrup were "up-grades". Without a bridle the force of the mainspring is on one side of the bearing (lockplate). This causes the tumbler to want to tip to one side causing pressure on the inside-lower and outside-upper surfaces of the tumbler hole and at two points on the tumbler axel. This pressure causes friction and wear which slows the rotation of the tumbler. The addition of the bridle largely eliminates both.
When an expansion spring is compressed it has the greatest energy to do work and the least energy when relaxed. This is a problem in a gun lock because we need the most energy at the end of the spring's power stroke to strike sparks from and push open a frizzen or pop a cap. The addition of a stirrup in the tumbler avoids this diminishing of force on the relaxing of the spring, and, depending on design, either maintains a constant force throughout the rotation of the tumbler, or actually increases this force toward the end of the stroke. Thus, a lock with both features is more efficient.

 

[tallPercshooter]

OK, if a stirrup design is better, explain to me why the best, most expensive lock available - the Kibler, as well as the standard of quality for decades - Siler, both do NOT use a stirrup,

 

[ronaldrothb49]

OK, if a stirrup design is better, explain to me why the best, most expensive lock available - the Kibler, as well as the standard of quality for decades - Siler, both do NOT use a stirrup,

Cheap locks don't have any of those. When you add the bridal You have added another part which also requires a modification to both sides of the tumbler to reduce friction so it can work better. Adding a fly involves another very small part and another modification to the tumbler in the form of a cutout for the fly. The stirrup adds another small intricate part and modification to both the tumbler and the mainspring. Each time you add additional work you add additional cost. I have a Robbins lock which has all those features, I bought it back in the early 80's for $150 at a time when a finished Siler was less than$100.

 

[LongWalker]

OK, if a stirrup design is better, explain to me why the best, most expensive lock available - the Kibler, as well as the standard of quality for decades - Siler, both do NOT use a stirrup,

The stirrup design is a later development. The Siler lock is a copy of an earlier (probably 1780-ish) lock. The Kibler Colonial is based on locks made in the period of the rifle design, so 1770-ish. On neither would a stirrup have been an original feature of contemporary locks. Note that Kibler's Ketland Import lock does feature a stirrup.

The stirrup showed up on later locks, towards the end of the primary original period of use of flintlocks. By the time caplocks were common, so were stirrups on locks, even on many relatively cheap locks.