Problem with Frizzen Screw

[KentSmith]

Last weekend I went to a shoot near Berkely Springs, WV.  A guy came up to me with a problem I have never seen before.  He had a trade gun with the L&R Queen Anne flint lock.  Every 20 shots or so the frizzen spring screw just shears off.  He digs the remains out of the hole, puts a new screw in and 20 shots later, shears off again.

Now when looking at it he had not replaced it again, it had no frizzen spring or screw in, the mainspring seemed normal for that lock, the frizzen still sparked well when fired but he couldn't carry it primed as without a frizzen spring the frizzen would flop around losing his priming.

I was guessing the frizzen spring might be too weak but this is a wild guess.  Am curious if anyone has ever seen this before?  He is going to call L&R but I am still puzzled.

[jerrywh]

 I have had a lot of problems with L&R lock parts being to hard. Every time I buy a L&R lock I temper all the internals and screws to 600°f for at least 20 minutes. I do not include the frizzen.  That always solves my problem with them. I believe that is his problem. A screw like that would not break off if it was tempered correctly.

[WadePatton]

... A screw like that would not break off if it was tempered correctly.

This assumes he is using only their screws for replacements.  But yeah, a screw that shears with no shearing load, does sound too hard. 

[jerrywh]

 brittle is the word.

[Stophel]

I've never seen ANY L&R lock part that was "too hard" (not by a LONG shot).... except the screws!  I don't know what type of material is used for their screws, but they are absolutely rock hard, through and through, and VERY difficult to anneal.  Put in an unhardened screw of normal steel, and I would think that it would be fine. 

[Bob Roller]

I have had to reslot some of the L&R frizzen pivot and frizzen spring screws and I had
to use a diamond coated knife file to do the job.

Bob Roller

[jerrywh]

 I have had sear noses and the tip of the tumbler break off on about three L&R locks they were all too hard. After tempering I never had any problems.

[KentSmith]

Thanks, makes sense.  I will have to see if I have the gentleman's contact and suggest he get anneal the replacement or make his own replacement.

[jerrywh]

 They don't need annealing. They need tempering.

[Cobweb]

I have had sear noses and the tip of the tumbler break off on about three L&R locks they were all too hard. After tempering I never had any problems.

This explains it! I have a .40cal. When it was originally built it was a flint gun. The fellow that bought it first converted it to percussion. After I purchased the gun, I just shot it that way.
I am now converting it back to flint. I was holding the lock and seeing what kind of sparks I was getting when something hit in my beard. Reached up and pulled metal out that used to be part of the sear.
I assume they are still available?

Cherry stocked, all iron furniture, 42" Bill Large barrel with L&R lock. $400
I had to think about the deal and that was what made me miss buying it the first time. This was 1977 tho!

[LRB]

  Temper as you think best, but I would not go beyond 450°/500°F max. Some steels start loosing  toughness and ductility between 400°F., and 700°. 01 steel is one of them. Stophel probably has one of the best solutions. Case hardened low carbon screws may be even better.  If those screws are of 01, 01 is at it's best in strength at 400°F, to 425°F. Roughly 60/61 Rc. Since we don't really know what steel these screws are, it may be best to stay below 500°F in temper.

[Acer Saccharum]

Even if you use a dead-soft frizzen spring screw, you're better of than one that is too hard. A soft screw may distort, but it's not likely to shear off. It also won't hurt the spring or lock plate.