Flintlock hammer profile advice...?? Before I make a mistake...

[Larks]

for my Baker rifle...

I’m having a lot of strike failures with my flintlock (my video from my “test fire” thread is here showing the problem ) and am trying to chase down the problem.

By strike failures I mean failing to strike the primer powder in the pan.

I took it out again today following previous suggestions and all started out well but after the third shot I started getting the same problem.

I tried cleaning the flint, hammer and pan with alcohol wipes but that didn’t work.

I changed the flint and got a good shot but then more failures......... all in all I got six good shots off through the session and all in a decent group at 50 metres, but of the six good shots I probably had about 10 failures.

I have ordered some different flints but I’m leaning towards the profile of the hammer possibly being the issue........

I had thought, from the strike pattern on the face of the hammer, that there may be a hollow half way down the face:

however closer examination shows the hammer to be slightly convex where the flint first strikes but actually quite flat as it comes down:

So I suspect that slight “hump” where the flint first strikes is re-profiling the flint just enough that after a couple of shots there’s not enough of it striking the hammer where it needs to in order to flash off the primer in the pan.

But before I go re-profiling my hammer face to get a flatter surface all of the way down, is there a proper way to go about ensuring that I do get the profile correct this time around?

I have good linishing belts and my plan is to anneal the hammer and then gently flatten the face over a wheel on the finisher with a fine belt before case hardening it again.

However I’m aware that there is a risk of messing up the face lengthways - ie possibly introducing a hollow (from the finishing wheel) on the downward face or down stroke of the flint onto the hammer while getting rid of the slight convex rise across the top of the face, so I’m a bit nervous about attacking this one......

 

[Comfortably_Numb]

My fist guess would be a improperly hardened frizzen

 

[Larks]

My fist guess would be a improperly hardened frizzen

I figured the same though I am still getting good spark and strikes initially. Either way I’ll re-case harden it when I re-profile and re-dress it and maybe give it a couple more cycles of hardening.

 

[dave_person]

Hi Larks,
How heavy did you make the feather spring? The frizzen should have considerable resistance to the striking of the flint. It seems your flint is scraping just at the top of the strike and then sliding over the battery. That could be a geometry issue but first make sure the feather spring gives the frizzen enough resistance so that it is not nocked out of the way too easily.

dave

 

[Larks]

Ian H did question the same thing when I did a thread on why my lock wasn’t fully closing Flintlock not fully striking/closing...any suggestions??, so I’ll have another look at hardening it up a little.

It’s a difficult one to weigh cleanly with the trigger pull gauge because of the shape but it was coming in at about 1.5 to 2lb, with the cock coming in at about 9.5lb

 

[IanH]

The face definitely needs some work, but I suspect your frizzen spring is far too weak.

I recall Dave Person recommending somethin on the order of four pounds to balance your mainspring.

 

[IanH]

I just remembered a good case in point about a good lock: one day I was shooting my Kibler SMR with homemade flint that had a crack in it. Sure enough, after a few shots the flint busted about 3/4 of the face off in a crescent shape. I dry fired it and got plenty of sparks and it wasn't tearing up the frizzen face so I kept using it. Got something like 25-30 more shots out of it before the flint wore down to a nub, bur zero klatches or hangfires. So even if your flint it only contacting part of the frizzen face it still ought to spark plenty well enough if the contact angle is correct and the springs are strong and balanced.

 

[Larks]

I just remembered a good case in point about a good lock: one day I was shooting my Kibler SMR with homemade flint that had a crack in it. Sure enough, after a few shots the flint busted about 3/4 of the face off in a crescent shape. I dry fired it and got plenty of sparks and it wasn't tearing up the frizzen face so I kept using it. Got something like 25-30 more shots out of it before the flint wore down to a nub, bur zero klatches or hangfires. So even if your flint it only contacting part of the frizzen face it still ought to spark plenty well enough if the contact angle is correct and the springs are strong and balanced.

Thanks Ian - I’ll concentrate on the spring as the first priority (you did warn me about it beforehand ) and will also give the hammer face a bit of a touch up and re-harden along the way. I’ll need to head down to the range and do some lead mining though, I’ve turned what I had into ball so will need some more for my feather spring heat treatment.

 

[Larks]

Well....unfortunately I’ve taken a bit of a step backwards with my first attempt at resolving this one, which is really frustrating

I’ve opened up the feather spring slightly and re-tempered it so that I’m now getting between 3.5 and 4 lb’s on it (it was 1.2 to 2 lb) and I’ve also dressed the face of the hammer so that it’s looking much more level across all the way down and I've re-case hardened it.

However I now have little to no spark and am back to the cock not always fully falling and the hammer/frizzen not fully opening.

I’ve tried different flints and different orientations of each.

I’m guessing that perhaps I’ll now have to open up the main spring a little more to balance it better with the feather spring and I’m wondering if perhaps I’ve case hardened the hammer too much......???

I gave the hammer three cycles with the Cherry Red case hardening compound after dressing it and it seems to be coming in between 50 and 55 Rockwell (hardness).


(The duplicated image of the hammer with engineers blue is out of sequence and was actually after the first strike only, thinking that it’d give me a clearer look at the strike)

 

[54ball]

Have you tried shorter flints? Have you notched the leather for cock screw? This will move the flint back slightly.
I know you have a lot going on with it but do not overlook the small stuff.

 

[Larks]

I hadn’t tried shorter flints, I’ve been using 1” flints that were recommended and I did try the same ones that were working a few days ago, without success. I do have the leather notched for the cock screw and I have also tried slightly longer flints which worked a few days ago, but not now.....

However - I’ve just pulled out the shortest one of the original pack of six that I have and it comes in at 7/8”, only just enough to clear the top jaw, but here’s the initial result.....:

 

[dave_person]

Hi Larks,
Don't give up on the spring tension balance. It is hard to help you without the lock in hand. I will be building a TRS Baker lock later this year so will have a lot more insight about their parts set in the future. The lock is relatively short throw compared with musket locks and thus the mainspring must be strong. I cannot give you a force estimate but consider strengthening the mainspring and then test to see if the feather spring needs to be weakened. The balance should really not be very finicky on a military lock but it may be in your case. The problem with flintlocks is you can rarely just change one thing. They are systems in which components are interlinked. Case hardening the steel with Cherry Red or any fast carbonizing compound will never produce a deep hardened surface. That requires either the frizzen be made of high carbon steel that can be hardened and tempered by heat treating alone or case hardening for several hours packed in charcoal. There are no good shortcuts. I believe TRS frizzens are cast from medium carbon steel that benefits greatly from proper case hardening in a charcoal pack. That is what I do with all of their frizzens.

dave

 

[Larks]

Hi Larks,
Don't give up on the spring tension balance. It is hard to help you without the lock in hand. I will be building a TRS Baker lock later this year so will have a lot more insight about their parts set in the future. The lock is relatively short throw compared with musket locks and thus the mainspring must be strong. I cannot give you a force estimate but consider strengthening the mainspring and then test to see if the feather spring needs to be weakened. The balance should really not be very finicky on a military lock but it may be in your case. The problem with flintlocks is you can rarely just change one thing. They are systems in which components are interlinked. Case hardening the steel with Cherry Red or any fast carbonizing compound will never produce a deep hardened surface. That requires either the frizzen be made of high carbon steel that can be hardened and tempered by heat treating alone or case hardening for several hours packed in charcoal. There are no good shortcuts. I believe TRS frizzens are cast from medium carbon steel that benefits greatly from proper case hardening in a charcoal pack. That is what I do with all of their frizzens.

dave

Thanks Dave. Yes I was thinking much the same - that it’d seem odd for a military rifle that had a reputation for being reliable would be so fussy on flints.

Using that shorter flint suggests that the hammer (frizzen) face is actually OK and is dressed about as good as I can get it (as good as I’m game to take it anyway), so I’ll take your advice and will definitely keep working on balancing the main spring and feather spring.

I went down to my local range yesterday to mine some lead so that I can temper the springs in my lead pot with a more controllable and measurable temperature. I thought it’d take me a few hours but the lead was so thick on the ground behind the targets that it came up in sheets so it took me less than five minutes to get as much as I could easily carry. (The pic below is about half of what I picked up - I just needed enough for my lead pot - about 4 or 5 of the bigger ingots - so that I could temper my feather spring but I melted and skimmed the crud (mostly copper) from half the haul in a tin bucket to come up with this.

I’ll be really interested to see your TRS Baker build when you get into it.

 

[IanH]

The first new video clearly shows the flint is too long as others mentioned.

The hammer face appears fire blued in the video, or is that marker or Dykem? Try polishing the frizzen face bright with sandpaper.

I don't think 50-55 Rockwell is quite hard enough, but I could be wrong. Like Dave wrote, a flint lock is a system and things have to work together. More throw (higher flint velocity) might work well with a frizzen that is more soft. The contact angle affects things too. 60-65 Rockwell seems to be a good number for me, closer to 60 is preferable.

 

[Larks]

The first new video clearly shows the flint is too long as others mentioned.

The hammer face appears fire blued in the video, or is that marker or Dykem? Try polishing the frizzen face bright with sandpaper.

I don't think 50-55 Rockwell is quite hard enough, but I could be wrong. Like Dave wrote, a flint lock is a system and things have to work together. More throw (higher flint velocity) might work well with a frizzen that is more soft. The contact angle affects things too. 60-65 Rockwell seems to be a good number for me, closer to 60 is preferable.

Thanks Ian. That was just some engineers blue that I applied for the first strike only to see how it fell, I wiped it off with alcohol after that first go but it’s out of sequence in the video