Mechanical Principles That Make a Lock Work Well

[Acer Saccharum]

Bevel up or down not only affects the height of WHERE the flint first touches the frizzen, but at what ANGLE the flint is in relation to the frizzen.

[hammer]

Chris, yes, that is the idea.  And the actual curve of the steel face is also a factor in ensuring that initial strike angle remains the same all the way down.  As the edge travels down the steel it also forces the steel to move back against it.  I think that is terribly clever.  At least that is how I see it.

And Tom, yes I understand your point and that can be necessary.   But if the flint has to be tried upside or downside, further out then expected or with the cock jaws crowding the steel face, does that not suggest the lock geometry isn't as good as it should/could be?    That is the distance between the cock and frizzen pivot points, the length of the pan cover, the throw of the cock, the curve of the steel?    So yes, it may be necessary but my suggestion is that it should not have to be necessary in a properly designed lock?   
Back into the fray ......

[Acer Saccharum]

Peter, I think in a properly designed lock one still must find what it likes to eat, and how it likes to eat it: What kind of flint, how far out from the jaws, what kind bevel attitude, etc.

Why should I not be able to just put a flint in my lock, and have it work perfectly?  Because it's too primitive a system, and there are SO many variables. So much of best functioning of the lock is left to the shooter to discover. That's what kind of system the flintlock it is.

As an illustration, the .22 rimfire has just about taken all the mechanical and human error out of the ignition system. Flint has a lot of 'operator experience required'.

[hammer]

Tom, couldn't agree more.  Except I don't hold that is just the way it will be.   It seems to me the very best lockmakers knew/know how to make that perfect lock.    Those I photographed in the local museum here in the UK were on top quality guns.   Different size locks of different styles but they had that right geometry.  Wish I had kept the photos but is was a while ago.   I just can't see that a master lockmaker would produce a lock that had to be fiddled with and tuned to get it to spark reliably.   (Of course not every one was a Master).  Yes, I have had to fiddle with a lock as well and helped others but that was because it had faults in design.  My suggestions are based on what  was and what should be today.   Sadly we have to deal with less than the very best and do that fiddling and then forgetting next time what we did with that particular gun!   In conclusion, I don't think the likes of Colonel Peter Hawker had to fiddle with the locks on his Joe Manton fowlers.   When a flint needed to be changed during a shoot I don't see he or his servant having to remember the peculiarities of that particular gun.  Especially as the servant may have been borrowed for the shoot.
Yes, I also prefer flint to anything else.    Can't beat it.   Flint is personal.

The trouble with making confident statements is that I lay yourself open to being publically proved wrong.

Peter.

[Acer Saccharum]

Peter, if we talk about the perfect locks of the 18th Century, then we are talking a different animal than the locks of today.

[Artificer]

Would there have been a difference in lock geometry for say gunspall flints vs regular flints?  The reason I ask is there seems to be many gunspall flints found in the archeological record.
Gus

[Habu]

In a discussion of mechanical principles, should we include proper lubrication?  These days I seem to see poor lubrication as a problem on the firing line more often than lousy lock design.  Then again, I seldom go to matches, so maybe it is just my small sample size. 

[Artificer]

I admit I don’t fully understand “balancing” the Main Spring to the Frizzen Spring and when it is necessary to adjust the “tip over” point of the Frizzen unless it is REALLY late.

As I understand it, the sear spring has to be strong enough to provide enough resistance for the frizzen to be struck well by the flint and scrape metal off for the sparks.  However, too much resistance will cause the flint to bounce and skip or break the flint.  When it is really too much, I got it, but not as much as when it still may need more adjustment.

I have all four JHAT volumes and have gone over them many times, but I guess I am missing the finer points of adjusting these two things.
Gus

[Acer Saccharum]

I've had a lock with too powerful for the frizzen spring. The frizzen would be thrown open with such force that it would bounce back and take 3/16 of the whole flint off. A self napping lock.

A weak main may not have enuff oomph to open the frizz entirely. Hammer gets stuck halfway thru its stroke.

Too soft a frizzen, and the flint embeds itself in the frizz.


What I'm trying to say about the perfect lock is that few makers today have the training or tradition that can create these perfect locks. Currently we are going through the re-invention process. We are not there yet. A perfectly made tuned and hardened Manton, made to the standards of the 18th Century, would probably cost you $1000 or more today. We are very lucky to have what we do. We have some remarkable locks to choose from. We have come a long way since 1960. We have a ways to go.

[Pete G.]

In my experience a good lock is not too fussy about flints and usually gives long flint life, whereas some of the import locks from back in the 70's (and a few today also) are very particular about flint length, bevel up or down, etc. A flint changes with every strike when it knaps off small flakes with every shot. I have locks that start with the flint just clearing the frizzen and go for 85-100 shots without having to knap, at that point the flint will clear the frizzen face by 1/4" or more, but still fire reliably. Then I'll just loosen the jaw screw, move the flint closer and continue for another 25 or 30.

I have also had a production Italian lock that had to be fiddled with about every 10 shots or so, and needed a new flint after 25 or 30 shots at the most. Good locks are what makes this fun. Bad locks are what sells cap guns.