Loose Hammer of Brown Bess

[Heelerau]

Gents, have an IMA Nepalese Bess with a loose cock, I could shim, upset with a chisel, someone suggested weld and file, if so ark weld or bronze? Would I have to harden the cock if I did this? Making another tumbler is out of the question. Shimming is my first thought. Any of you out there cured this problem on a side lock of any sort?

cheers

Heelerau

 

[Grizzly Adams]

Is the cock screw loose? How about the bridle screws? It may not be a wear related issue if that's the case.

 

[bpd303]

I have used the chisel method to tighten up several percussion hammers on the tumbler shaft. Haven't had them loosen after many shots. I found two of my old 1800 era smoothbore's had the hammers tightened that way too. Must have been used often back in the day.

 

[bpd303]

Here is one of the old ones. I don't see why it wouldn't work on an old flintlock cock.

Just use a small Cole chisel.

 

[Artificer]

Shimming with either brass or mild steel shim stock often is the best and most lasting of the easier ways to fix a loose cock/hammer.

If it is a particularly loose fit and a replacement tumbler is out of the question, then using a lead free soft solder or low temp silver solder to solder a/some steel shim/s to the tumbler may be the best way to go.

Having mentioned this, are you sure there is not a reproduction tumbler that would fit correctly and could be fitted to the lock? There are many blank tumblers and cast tumblers in many sizes and one might be found that would not require too much fitting. Case hardening and annealing it afterwards is not extremely difficult.

Gus

 

[matt denison]

Cocks are soft. Tumblers are hard. When a cock gets loose it's because the hole in the soft hammer (cock) has walloed out. Easy fast efficient fix is a couple of smacks on the backside with a punch or chisel to move metal back into the square hole then refit onto the tumbler shaft nice and tight. No heating or soldering, no mess or fuss or discolloring the metal by heating.

 

[Artificer]

Cocks are soft. Tumblers are hard. When a cock gets loose it's because the hole in the soft hammer (cock) has walloed out. Easy fast efficient fix is a couple of smacks on the backside with a punch or chisel to move metal back into the square hole then refit onto the tumbler shaft nice and tight. No heating or soldering, no mess or fuss or discolloring the metal by heating.

Yes, I realize that and have done it on a number of occasions for urgent/emergency use to get a shooter back on the line as fast as possible at NSSA Spring and Fall National Championships. However, a longer lasting fix is to use shim stock, whether one solders it or not. There may even be some newer glues where one would not need to solder them on.

Gus

 

[LRB]

It may be possible to find square tubing in a good hobby shop that may be close enough to file fit as a shim sleeve. Just thinking out loud. There are many sizes in brass. Not sure about steel, which would be preferable, if available.

 

[Artificer]

It may be possible to find square tubing in a good hobby shop that may be close enough to file fit as a shim sleeve. Just thinking out loud. There are many sizes in brass. Not sure about steel, which would be preferable, if available.

Never thought about trying brass tubing to use for shim stock. Going to have to do some checking on what sizes are available next time I go to Pleasant's Hardware Store. (If they don't have it or can't order it, you don't need it. GRIN.)

Over the years, I managed to scrounge steel shim stock from our own Machine Shop and other places. I've even sacrificed a couple cheap feeler gages when I needed a particular size thin piece of steel for shim stock. Brownells sells a modest set of steel shim stock for about $20.00.

I don't remember where I purchased my brass shim kit. It ranges from .003" to .022" and is one of the best purchases I made back in the late 80's. I have used it many times and still have a lifetime supply for my needs. Grin.

Gus

 

[matt denison]

"
Yes, I realize that and have done it on a number of occasions for urgent/emergency use to get a shooter back on the line as fast as possible at NSSA Spring and Fall National Championships. However, a longer lasting fix is to use shim stock, whether one solders it or not. There may even be some newer glues where one would not need to solder them on.
[/i

So how much longer is a "longer lasting fix" than forever? And where do you propose finding shim stock only 1-3 thousandths? Tin foil. Yeah, that will last a long time. And why bother to solder it if the cock screw will hold it in there? Why make these teeny tiny repairs as complicated as your imagination can make it? :hmm:

 

[Artificer]

You said yourself that "Cocks are soft. Tumblers are hard." By peening metal, even with a punch ground to fit the sides of the square notch of the hole in the cock, you just move a small amount of soft metal on the surface that will wear loose much faster than the original metal surrounding the square shaft of the tumbler. That is OK for an urgent/emergency fix, but it will not last long. It will normally last through a day or weekend shoot. It may even last a few weeks or months; but it is hardly a permanent fix for a gun that will be shot a good deal.

Shim stock goes further up in the notch of the cock and fills in the open space better and not just near the surface of the cock. Even thin brass shim fills in more of the open area to give more surface contact of metal to metal fit of the tumbler square to the cock. That lasts longer than peening a small section. Soldering on a steel shim lasts longer still.

Of course, the best ways are more difficult. One is weld up the hole in the cock, dress the tumbler square and cut the hole in the cock to fit. Or replace the tumbler with one that has a larger square shaft that can be fitted to the cock.

Gus

 

[LRB]

That has been my experience also Gus, but others may have had better long term luck than I with the peening fix. Thinking on it, You might only need to shim two adjoining sides, so a piece of thin angle stock may work as well as tubing. You ever try that, or is that a common way of shimming a cock?

 

[Loyalist Dave]

Cocks are soft. Tumblers are hard. When a cock gets loose it's because the hole in the soft hammer (cock) has walloed out

This is often true, but here we are dealing with an antique from Nepal sold by IMI, so you could have a cock that doesn't originally go with that lock, or a cock (hammer) screw that doesn't go with the lock and is too long, allowing the cock to wiggle since it simply isn't able to properly tighten.

THEN folks ask the fellow if he plans on shooting this piece, or simply wants a wall hanger without the cock rattling about when he takes it down from time to time to clean it or to show it to somebody?

IF one is shooting, then yes of course one needs a really durable fix. Best to have it welded, then hand filed to adjust the â–  to fit. (A brass shim? Brass is softer than steel, not sure how that's a long term fix) BUT...if he's just adjusting a wall hanger...then peening the inside edge of the â–  will do very well.

LD

 

[Artificer]

That has been my experience also Gus, but others may have had better long term luck than I with the peening fix. Thinking on it, You might only need to shim two adjoining sides, so a piece of thin angle stock may work as well as tubing. You ever try that, or is that a common way of shimming a cock?

You are correct that using the shims on two adjoining sides is a fairly common way of shimming the hole.

The most shims I ever saw was two on opposing sides and another shim that sort of formed the bottom of a "U" of shims around three sides of the tumbler. It was on a repro Italian Rifle Musket lock. It was TIGHT. It actually lasted a few years in a gun that was shot very often in practice and NSSA competition.

Gus

 

[Artificer]

Cocks are soft. Tumblers are hard. When a cock gets loose it's because the hole in the soft hammer (cock) has walloed out

This is often true, but here we are dealing with an antique from Nepal sold by IMI, so you could have a cock that doesn't originally go with that lock, or a cock (hammer) screw that doesn't go with the lock and is too long, allowing the cock to wiggle since it simply isn't able to properly tighten.

Good point. Or the square of the tumbler sticks out beyond the outer edge of the cock and the cock screw head doesn't tighten against the outer edge of the cock. The tumbler square needs to be not quite flush with the outer edge of the cock so the screw head holds with friction compression.

THEN folks ask the fellow if he plans on shooting this piece, or simply wants a wall hanger without the cock rattling about when he takes it down from time to time to clean it or to show it to somebody?

Good point. If it is never going to be shot, then peening the hole in the cock will work.

IF one is shooting, then yes of course one needs a really durable fix. Best to have it welded, then hand filed to adjust the â–  to fit. (A brass shim? Brass is softer than steel, not sure how that's a long term fix) BUT...if he's just adjusting a wall hanger...then peening the inside edge of the â–  will do very well.

LD

This is another of many times over the years that folks have found something that works and then try to explain it. Sometimes Mechanical Engineers can explain something and sometimes even they can't, but I am not a Mechanical Engineer. So please bear with me as I try to explain.

It is a well known principal to Mechanical Engineers that compressed paper can be stronger than steel. I can't explain why in Engineering Terms, but having spoken with many Mechanical Engineers at White's Laboratory and other places, they all informed me this is correct. The key factor is compression in what Machinist's call an Interference Fit of parts. This last is how the square of the tumbler is supposed to fit in the cock when first fitted.

As an example, let's say there is .003" of open space or "slop" between parts. If you use a .001" to .002" brass shim, there will still be slop or looseness between the parts. If you use a .003" brass shim, there should be little or no slop or looseness between the parts and the fit may be rather tight. However if you use a .004" brass shim, that shim will be compressed and hold better due to the compression and it will be VERY tight and long lasting. Sometimes you can get compression with steel shims and sometimes you can't, it all depends on how hard the cock is OR how tough the steel in the cock and/or shims are by the metallurgy of their alloy. (For example: Barrels are not hard, rather they are tough by the metallurgy and that's how they hold high pressures [within the range of each alloy] and without permanently deforming from firing the shot/s.)

Unless the tumbler square and square hole in the cock are very high quality, the sides won't be almost perfectly flat. If you take disassemble a cock and tumbler, colour the mating surfaces with layout dye or magic marker or candle black, reassemble the parts and then take them apart again; you will normally not see wear of the colour that shows complete surface to surface contact. When using an interference fit with a slightly larger brass shim, it still may not show complete wear of the colour, but it will show more wear and that means you have a tighter fit. It will also show where the brass got compressed, even if there is no colour on the brass shim. So the brass shim get's compressed where the two surfaces of the parts normally meet well and "fills in" some of the space where the parts do not match up well.

A rather extreme example of a compression fit was when my best friend in life installed a stainless steel liner in a cast brass/bronze swivel gun. He took it into a General Electric Machine Shop he worked at during "third trick" and many of the machinists got involved in doing it on "Government Time" after they finished their normal work quota for the night. One guy precision reamed the swivel gun. Another guy turned a stainless steel liner to just over the internal diameter of the hole in the swivel gun. Then another guy used dry ice to cool the liner. Another guy heated the brass/bronze tube. Then they put the barrel in a large vise and pressed the cold liner into the warm barrel using a hydraulic press. When the barrel cooled and the liner warmed up to room temperature, the two parts were virtually friction/compressed welded together and never came apart.

Gus

 

[LRB]

Although I know what you're saying and mean, but technically and scientifically, metal cannot be compressed. You can make minute dimensional changes with heat or cold, but not with force or pressure. Something has to give, somewhere. I would call it a pressed fit, or a friction fit.

 

[Artificer]

OK, I can certainly go along with that.
Gus

 

[pargent]

Go WITH THE PEEN FIX ,as to how good this works depends on how good the person doing the job is , personaly as an example of the extreme with this fix I have watched as a high pressure steam leak at a flange was repaired on line buy peening the flange .

 

[vulture]

Years ago I had an Italian made sharps rifle, didn't like the hammer or the stock block, so I ordered an original 1874 Sharps hammer from Dixie, then cut down the breach block and redesigned the firing pin. The original hammer was loose on the tumbler shaft so I went to my local hardware store and picked up a cheap sparkplug gauge, the type that has all the little blades that fold out. I used the right size blade to shim that hammer and it was rock solid, just had to remember if I removed the hammer for any reason to catch the shim so I could replace it. I've cut pieces off the gauge many times to shim something up, or check the headspace on a rifle, they work great and are quite cheap, and best of all you have all different thicknesses to work with.

 

[M. De Land]

I would TIG weld, anneal, file to fit and re-harden. A job worth doing at all is worth doing right!
You'll need to draw the temper after hardening also.