Converting to musket caps?

Newly O’Brian said:

I've done three conversions to musket caps.

All of them, I've had to bend the hammer, so the nipple is CENTER of the hammer nose and doesn't catch the hammer skirt

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smoothshooter said:

What method did you use to bend the hammer?
I have a new 1842 Harpers Ferry .69 smoothbore whose hammer cup is off location some. I have been hesitant to heat and bend it because if I break it it may be almost impossible to get a replacement from Italy, based on their manufacturing problems from a big part of their skilled labor work force being killed by the China Virus.

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Notchy Bob said:

As long as the rim of the hammer nose clears a capped nipple, your best bet may be to just try to live with it. If the rim of the hammer cup is hitting the cap, you may need to bend it.

I’ve bent hammers from sporting locks a time or two, and found it a tricky procedure to get right. You remove the hammer from the lock, clamp it in a fixture such as a vise with smooth jaws, heat the area that needs to be bent red hot with a torch, and then bend it with a smooth-jawed wrench. A MAP torch (with the yellow canister) gets hotter and works better than a propane torch (a nod of appreciation to forum buddy @Howard Pippin for suggesting that). The other thing is that the amount you need to bend will likely be very small… as little as 1mm one way or the other can make all the difference.

Bending the hammer nose of a sporting rifle left or right is easy this way. The trick is in knowing how far to bend it, and that may take several tries. Bending the hammer nose forward or back, on the other hand, is a whole different can of worms. I found this very difficult to do without leaving deep tool marks in the red-hot hammer. It was also hard to avoid distorting the cup in the hammer nose.

Musket hammers are massive in comparison to hammers from sporting arms, and I have not tried to bend one. You would think the procedure would be the same except for needing more heat and more time, but I can’t confirm that.

One other point concerns replacement parts. It is generally easier to find original US military musket parts than reproduction parts, and the originals are often cheaper. The problem would be with interchangeability… some parts interchange and some don’t, and I don’t know about the hammer on your M1842 replica. However, it might be something to keep in mind.

Again, if your musket works as it is, you needn’t worry about having the nipple exactly centered in the hammer cup. I would only try to bend it if there is actual interference.

Good luck with it!

Notchy Bob

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smoothshooter said:

I’m thinking of shimming the top inner edge of the lock mortise with a narrow strip of VERY, VERY THIN shim stock ( maybe only .010”) to tilt the lock plate and hammer away from While that amount won’t center the cup on the hammer nose on the nipple, it may be just enough of a correction to keep the side of the cup from battering the corresponding side of the nipple.
Or, it just occurred to me I could simply install a .015” washer between the hammer and the step on the square shank that passes thru the lock plate.

Click to expand...

smoothshooter said:

I’m thinking of shimming the top inner edge of the lock mortise with a narrow strip of VERY, VERY THIN shim stock ( maybe only .010”) to tilt the lock plate and hammer away from While that amount won’t center the cup on the hammer nose on the nipple, it may be just enough of a correction to keep the side of the cup from battering the corresponding side of the nipple.
Or, it just occurred to me I could simply install a .015” washer between the hammer and the step on the square shank that passes thru the lock plate.

Click to expand...

Notchy Bob said:

Either of those may work, and would be easily reversible if they don’t. You might even try shimming the lock plate with very thin cardboard or heavy paper for testing before you invest time and treasure into shim stock.

The washer under the hammer has some potential, but if you hold the lock up and look between the hammer and the lockplate you should see daylight. When the hammer is fully seated on the tumbler shank, it should not be contacting the lockplate. Installing a washer should move the hammer out so the cup will clear the nipple, but it will likely contact the hammer and the lock plate, and introduce a good deal of extra friction into the movement of the hammer, slowing its movement and absorbing some of its power. Also, as the washer/spacer wears the hammer screw will need occasional retightening. Just some things to ponder.

Part of the fun in muzzleloading is in problem solving.

Notchy Bob

Click to expand...

Notchy Bob said:

Either of those may work, and would be easily reversible if they don’t. You might even try shimming the lock plate with very thin cardboard or heavy paper for testing before you invest time and treasure into shim stock.

The washer under the hammer has some potential, but if you hold the lock up and look between the hammer and the lockplate you should see daylight. When the hammer is fully seated on the tumbler shank, it should not be contacting the lockplate. Installing a washer should move the hammer out so the cup will clear the nipple, but it will likely contact the hammer and the lock plate, and introduce a good deal of extra friction into the movement of the hammer, slowing its movement and absorbing some of its power. Also, as the washer/spacer wears the hammer screw will need occasional retightening. Just some things to ponder.

Part of the fun in muzzleloading is in problem solving.

Notchy Bob

Click to expand...

Notchy Bob said:

As long as the rim of the hammer nose clears a capped nipple, your best bet may be to just try to live with it. If the rim of the hammer cup is hitting the cap, you may need to bend it.

I’ve bent hammers from sporting locks a time or two, and found it a tricky procedure to get right. You remove the hammer from the lock, clamp it in a fixture such as a vise with smooth jaws, heat the area that needs to be bent red hot with a torch, and then bend it with a smooth-jawed wrench. A MAP torch (with the yellow canister) gets hotter and works better than a propane torch (a nod of appreciation to forum buddy @Howard Pippin for suggesting that). The other thing is that the amount you need to bend will likely be very small… as little as 1mm one way or the other can make all the difference.

Bending the hammer nose of a sporting rifle left or right is easy this way. The trick is in knowing how far to bend it, and that may take several tries. Bending the hammer nose forward or back, on the other hand, is a whole different can of worms. I found this very difficult to do without leaving deep tool marks in the red-hot hammer. It was also hard to avoid distorting the cup in the hammer nose.

Musket hammers are massive in comparison to hammers from sporting arms, and I have not tried to bend one. You would think the procedure would be the same except for needing more heat and more time, but I can’t confirm that.

One other point concerns replacement parts. It is generally easier to find original US military musket parts than reproduction parts, and the originals are often cheaper. The problem would be with interchangeability… some parts interchange and some don’t, and I don’t know about the hammer on your M1842 replica. However, it might be something to keep in mind.

Again, if your musket works as it is, you needn’t worry about having the nipple exactly centered in the hammer cup. I would only try to bend it if there is actual interference.

Good luck with it!

Notchy Bob

Click to expand...

smoothshooter said:

Have not had it apart yet, but doesn’t the

Have not had it apart yet, but doesn’t the square hole in the hammer rest against a stop on the tumbler shank? I was going to use a washer that I filed a square hole in and slide it down the shank to the stop. The washer would never touch the lock plate.
Will advise on how it works out.

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