A Brief Tour of a Really Good Musket Lock

[smart dog]

Hi,
I've been attending quite a few Rev War period living history events over the last few years and it is clear that many Rev War units are getting pretty old.  I noticed that some folks struggle to cock their muskets because the springs are often way too stiff and they are not as strong as they once were.  So, when I can and have time, I will help some of those folks "age in place" with their musket locks.  That means I weaken the mainspring and balance the frizzen spring along with it.  The end result is as good or better performance without so much strain.  Ironically, I usually have to strengthen the frizzen spring because many reenactors subscribe to the notion that the frizzen spring just needs to be strong enough to hold the pan cover closed.  That is one reason why when they pull the trigger 10 times, they have 3 misfires. They don't believe me when I tell them the British Army expected their Brown Bess lock to ignite the pan priming 40 times in a row with no misfires and using 1 flint. 

At Kempton, a friend handed me his Navy Arms Charleville musket to "age in place" his lock and improve its performance.  These muskets were made by Miroku and were the best reproductions of any Rev War musket commercially made.  The lock is superb and I just needed to clean up the lock, polish the bearing surfaces, weaken the mainspring, and adjust the frizzen spring.  I also adjusted the sear spring to allow a lighter trigger pull.  I had not worked on one of these for years and forgot how good they are.
   




The musket reproduces the French model 1766 or 1768 infantry musket.  It was also known as the "light 63" because it was a substantially lightened version of the first model 1763 musket issued.  Didier Bianchi wrote in his book "French Military Small Arms" that the locks on these muskets were the best flintlocks ever used on French muskets and probably on any 18th century muskets.  They were expected to ignite the pan 120 times without a misfire and using only 3 flints in the process. There are many features of this lock that are superior to the British Brown Bess locks.  The double throated flint cock is incredibly strong and the geometry of the lock puts the sparks right in the pan.  The throw of the cock is shorter than the Brown Bess making it a faster lock.  The detachable pan is a very nice feature when it comes to cleaning and servicing the lock. One feature I wanted to highlight is the way the mainspring and tumbler interact. The first photo shows the hook of the mainspring on the tumbler foot when the lock is at rest.



The next photo shows the lock at full cock.  Note the end of the hook is positioned right in the inside corner of the tumbler foot.  What happens, is the tumbler both lifts the spring up as you cock the lock but also rotates around the round nose of the mainspring hook.
 


In the photos below, the black tape marks the position of the mainspring at rest showing how far the spring moved going to half cock.  Then the tape is moved up and the lock is drawn to full cock so the tape shows how little the spring moved from half to full cock. That combination of limited movement up and rotation of the tumbler around the hook provides mechanical advantage making the force required to pull the lock back to full less than the force required to pull it to half cock. That offers options for a lighter trigger pull without sacrificing any power in the mainspring. It is an excellent design and Miroku did a great job reproducing it. 






Of course the proof is how well does it spark. Even with a dull flint it does really well!  In the last photo, which is the next instant after the second photo was taken, you can see residual sparks still burning inside the pan and out like a sparkler.







This lock teaches a lot about good lock design.

dave

[bob in the woods]

Thank you for this very informative post 

[Bob Roller]

A very basic and simple mechanism that demonstrates total functionality and a properly hardened
frizzen that will allow it to fire the gun.
Thanks for showing this one.
Bob Roller

[Steeltrap]

Very informative post.

And it's likely posted somewhere else but how do you "weaken" the mainspring?  And of course, how do you "strengthen" the frizzen spring?

I can understand the need for a strong frizzen spring that will allow the flint to hit a relative "hard to move" surface thus allowing the flint to "chip off" those much needed tiny hot pieces of metal into the pan.

I can understand the need for the "balance" of the springs as you stated.....but getting the springs to these correct tensions has to be more of a "feel" than the ability to measure with some type of device.  My guess?

Thanks again for your great information!

[Daryl]

Food for thought:
I broke the feather spring on my L&R Dickert lock on the trail. This lock always gave a huge shower of sparks into the pan and even Taylor said, "that is the
fastest firing lock I've seen, even faster than my chamber's locks".
While shooting it without the feather spring is particularly hard on the frizzen itself, I continued to finish the trail with it, no feather spring and same wonderful
ignition. I acknowledge few (perhaps], L&R locks are of this "quality", this one certainly is and with NO balance between main and feather springs, it still gave
it's normal, fast ignition. Perhaps something other than spring "balance" is more important to good function?

[smart dog]

Hi,
Thank you all for looking.

Steeltrap,
I have no issues with annealing hardened lock parts, reshaping them, and then hardening and tempering them again.  To weaken the mainspring I first ground the bevel on the sides wider.  That often is enough but not on this heavy spring.  It was really strong.  Consequently, I heated the spring red hot, closed the main bend just a little and gave the lower leaf a slight downward curve.  I then thinned the lower leaf a little.  To strengthen the frizzen spring, I heated it red hot and bent the upper leaf upward slightly. The both springs were polished, heated to bright orange red with a MAPP gas torch and quenched in 2" of canola oil floated on top of a #10 can filled with room temperature water. Because I do not know the steel alloys used in the parts, I take an extra step before hardening by heating the springs bright red and then letting them cool almost to the touch, then heating them back up to bright orange red and quenching.  The cycle of heating and cooling helps to "normalize" the steel, making it more ductile and strengthening it.   I generally want the force required to open the frizzen to be about 30% of the peak force required to pull the cock back from rest to full cock.  That is my starting point and then I go from there depending on the lock.  If the cock has a short throw, that formula of relative forces usually works well.  I never let the force of the frizzen spring drop below that 30%. If it has a long throw, like a musket lock, I'll up that force.  If the lock has a roller in the frizzen spring or frizzen toe, I have a completely different strategy altogether, which I won't go into here. I don't know where so many reenactors get the notion they have to have really anemic frizzen springs.  Somebody has misinformed them.  They often come to me because the frizzen won't open all the way and they think the frizzen spring must be too strong.  I close the frizzen and there is almost no tension at all.  What is happening, their frizzen spring is so weak the frizzen rebounds and closes partially. They never believe me until I put a piece of tape on their frizzen spring where the toe of the frizzen will hit when fully opened. They fire the lock and "lo and behold", the tape has a dimple in it.  Then I strengthen their frizzen springs and their lock works great, and they are surprised.  If you want to see this weak spring nonsense in action, just go find the documentary on the American Revolution hosted by Bill Curtis:

.

In the opening credits, a soldier fires his Pedersoli Brown Bess in slow motion and you can watch the frizzen open, then rebound hitting the flint again, and then open again.  I call them "bobblehead" frizzens because they wobble around like the bobbleheads people put in the rear windows of their cars.  The beginning also shows a line of British soldiers firing their muskets.  If you look closely, only half of the muskets fire.   

Bob Roller,
Thanks for commenting.  The frizzen sparked pretty well when I got the lock.  I improved it by case hardening the frizzen in charcoal for 2 hours.  Then tempering it properly.

dave

[smart dog]

Food for thought:
I broke the feather spring on my L&R Dickert lock on the trail. This lock always gave a huge shower of sparks into the pan and even Taylor said, "that is the
fastest firing lock I've seen, even faster than my chamber's locks".
While shooting it without the feather spring is particularly hard on the frizzen itself, I continued to finish the trail with it, no feather spring and same wonderful
ignition. I acknowledge few (perhaps], L&R locks are of this "quality", this one certainly is and with NO balance between main and feather springs, it still gave
it's normal, fast ignition. Perhaps something other than spring "balance" is more important to good function?

Yes Daryl, geometry of the lock.  The point I'll make here is that folks are obsessed about the speed of ignition.  It doesn't really take much to make a lock that is fast for a few shots but it takes much more if that lock remains reliable after 20-30 shots without changing flints, and on a musket during battle, not cleaning the lock all day.  One of our shooters broke his feather spring on an L&R Queen Anne lock.  He tried shooting it without the spring and the frizzen broke at the hole on the first shot.  Nor did it ignite the pan.  Here is a Chambers late Ketland lock, which is acknowledged to be fast and reliable.  I took off the frizzen spring. I installed a dull flint and gave it a very thin coat of tooth paste to simulate greasy fowling.  Then fired it.




I fired it again with no lights but the captured photo was simply black.

Next I put the frizzen spring back on, using the same flint and with another thin coat of tooth paste, I fired it.




And then fired it again with no lights on.




dave

[Hungry Horse]

 I have one of these locks. It is very hard to even cock it out of a gun. I lightened and polished the springs, and removed the French markings. This lock was also used on Russian muskets of the time period. Some of which saw service at Ft. Ross on the Northern California coast, and Alaskan.
 They also can represent an earlier French lock with very little work.

Hungry Horse

[Dennis Daigger]

Thanks for this post, Dave. It is very informative and useful. The lock spring balancing is starting to make sense to me.
Dennis

[Steeltrap]

Very interesting post and thanks for the information.

Now, is it possible to fit an L&R mainspring to a factory T\C flintlock?  I have the T\C factory lock on a kit rifle I put together (I won't say "build" 'cause that really wasn't what it was).

I would think the lock could then be better tuned. The spring for the T\C replacement lock is like $32 vs $220 for a replacement lock. Drilling\filing out the lock plate for the replacing the coil spring with the  replacement L&R main spring seems like something that could be done, but worth the effort to make the lock better?

[smart dog]

Hi Steeltrap,
I haven't worked on a TC lock for so long that I forget what they look like.  I suspect you would need to change all of the guts to install a proper "V" spring.  I doubt it would be worth it.

dave

[Steeltrap]

Hi Steeltrap,
I haven't worked on a TC lock for so long that I forget what they look like.  I suspect you would need to change all of the guts to install a proper "V" spring.  I doubt it would be worth it.

dave

Yeah. Thanks SD. My T\C is simply for hunting. I changed the barrel to a GM many years ago. Best swap of a component I've ever done. I put a $200 barrel on a firearm worth $200 at best....but now it will shoot the "eyes outta fly's" at 100 yards!

I'd spend the $32 to make the lock better.....but that's about the max!

[Kevin Houlihan]

Steeltrap,
 I found pics online of the internals of a TC lock.  The lock has a coil spring and therefor you can't replace the coil spring with the "V" spring from one of the L&R locks.  You can install an L&R RPL lock made for the TC, but if you're not having specific problems w/ the TC lock I wouldn't bother.  I have an L&R RPL lock on a Dixie Mountain rifle and while it's better than the original lock, it's still not that great.  The lock that I bought new was pretty "sloppy" for lack of a better term.
Good luck,
Kevin   

[Bob Roller]

Hi Steeltrap,
I haven't worked on a TC lock for so long that I forget what they look like.  I suspect you would need to change all of the guts to install a proper "V" spring.  I doubt it would be worth it.

dave

Yeah. Thanks SD. My T\C is simply for hunting. I changed the barrel to a GM many years ago. Best swap of a component I've ever done. I put a $200 barrel on a firearm worth $200 at best....but now it will shoot the "eyes outta fly's" at 100 yards!

I'd spend the $32 to make the lock better.....but that's about the max!

No gunsmith worthy of the name that has skills will let anyone tell him what his time is worth.I never claimed to be a gunsmith and still don't but nobody tells me what my time and skilled labor is worth in my own shop.The use of the shop,the machines,cost of material plus the willingness of the man and the cost of electricity must be factored into the equation.
Bob Roller

[heinz]

Nice post SmartDog and great photos.  Thanks for putting that up.