Cook Bros. lock problem

[Artificer]

Thanks, but pulling the trigger as hard and fast as I can, still falls to half cock every time. Just wondering, would the small spring above the trigger prevent the sear from rising up enough to clear the half cock notch?

A Cook and Brothers rifle musket uses the P1853 Enfield Pattern Lock.

That small spring above the sear is the sear spring. Though it is not very likely, it is possible that spring can cause the sear not to be able to move up high enough so the sear nose clears the half cock notch. You test for that with the hammer forward and down and pushing up on the tail of the sear. If it does not lift the sear nose well clear of the tumbler, then you may have the following problem.

When this happens, what causes it is if the lower leaf of the sear spring is too long and binds up on the sear bolster. That bolster is the round part of the sear the sear screw goes through. The lower leaf spring is not supposed to touch the bolster even when the sear tail is pressed as high as it will go. Again, though it is not likely this is the problem, the fix is to carefully file the lower leaf a little shorter at a time until it no longer binds against the bolster. The lower leaf of the spring must still contact the top of the sear at all times, though. Be careful, if you grind or file too much, then the lower leaf may/will not press on the sear correctly. The few times I have had to do this after working for many years on Rifle Musket locks, when you have to shorten the lower leaf - it usually means shortening it around 1/16" or maybe a tiny bit more than that.

There are many other things that can cause the problem you are having.

You mentioned it still happens when the lock is removed from the stock, correct?

One of the more common things is if someone tightened down the sear screw and or bridle screw too tight when they assembled the lock and did not know you don't tighten those screws down fully tight. To keep that from happening, one does things to check for binding when one re-assembles a lock. When the lock has just the tumbler and hammer in place and you place the bridle over the tumbler - when you tighten the screw, you must check that the tumbler moves freely. If the tumbler binds, you back the screw off JUST ENOUGH so the tumbler moves freely. Then when you put the sear and sear screw in place and tighten the sear screw down it will bind up the sear if tightened too much. Again, you back off the sear screw JUST ENOUGH that the sear moves freely. Then finish reassembling the lock.

However, I strongly suspect that since the hammer has been hitting the half cock for some time, that either the sear nose is damaged or the full cock notch is damaged or improperly shortened without shortening the half cock notch. If neither sear nose or full cock notch on the tumbler is damaged, then you probably need to shorten the half cock notch a bit.

Before we go further, do you have the tools and know how to disassemble/reassemble an Enfield Lock?

Gus

 

[Artificer]

I wonder if this may be a trigger problem, not lock. Maybe the trigger bar(?) is not pushing the sear arm up enough to override the half cock notch.

This almost never happens with repro rifle muskets UNLESS someone shortened the top flat part of the trigger, after it left the factory. I have seen that a couple of times in all the years I worked locks at the NSSA Spring and Fall National Championships, though it was always done later on. Normally done by someone attempting to do a trigger job and not knowing the correct way to do it.

The best place to begin is to get the lock working correctly outside the stock and then attending to problems that can cause the hammer to hit the half cock when the lock is assembled to the stock.

Gus

 

[snubnose57]

The only sign of amateur gunsmithing, is the sear spring screw head is buggered up a little.
The sear and notches look as they have been untouched. Maybe a little filing on the edge of the half cock notch may do the trick.
I have never taken a lock apart, but the internet should help with that.
Also, would a musket lock have a fly?

 

[Artificer]

Sorry to take your questions out of order, but I think it important to do it this way:

Also, would a musket lock have a fly?

The only “Rifle Musket/Military Arms” that commonly came with a fly in the Tumbler was the REAL Parker Hale Whitworth Rifle and perhaps the Volunteer rifle, though I don’t remember if the latter did or not for sure. However, a Real Parker Hale Whitworth Tumbler with Fly would have had to been specially fitted to your lock and I highly doubt that happened, unless you got the rifle from an NSSA Skirmisher or other Target shooter. I don’t think EuroArms had a fly in their Tumblers when they copied the Whitworth and Volunteer rifles. So I would be VERY surprised if you had a tumbler with a fly in your lock.

The only sign of amateur gunsmithing, is the sear spring screw head is buggered up a little.

That well could be a sign of someone tightening up the sear screw too much and thus the bridle is binding the sear and not allowing it to move up as high as it should to clear the half cock notch. So the first thing to do is disassemble the lock and see if that is causing the problem. Already mentioned the “fix” for that is backing off the screw JUST ENOUGH to allow the sear to move freely.

The sear and notches look as they have been untouched. Maybe a little filing on the edge of the half cock notch may do the trick.

The first thing to do is ensure the bridle screw and then the sear screw are not too tight and causing binding. If after you correct that, the sear is still catching in the half cock notch, then yes, filing some off the outer edge of the half cock notch may well cure the problem

I have never taken a lock apart, but the internet should help with that.

OK, I went looking for some videos on disassembly/reassembly of the P1853 Lock and could not find a good one. Some had some really bad ways to do some things.

Some information peculiar to your lock.
The mainspring is connected to the tumbler by an “S” shaped part that is called the Stirrup. Some of these will work whichever way you put them on the tumbler and some will only work correctly with one side up. So before you take off the mainspring, I would suggest marking the bottom part of the Stirrup so you will get it back the way it was in the lock. BTW, sometimes when you put a stirrup in upside down, it will also cause binding of the tumbler. If it does bind up the Tumbler, then take the mainspring off, turn the Stirrup upside down and reinstall it and usually that will free everything up.

The surface hardening of the tumbler is not so deep that a file will not cut through it, normally. You just have to be careful on the first few strokes of the file as you cut through the surface hardness. Of course if you have a diamond flat needle file, that will cut right through the surface hardness.

Though the Tumbler shown in the following link is a Springfield Tumbler, it is close enough to a Enfield Tumbler for our purpose. Scroll down to Figure 3. In the following link for the correct way to take metal off the half cock notch and blend it in a curved manner forward on the tumbler. http://www.nwtskirmisher.com/useful-locks.shtml

A couple of important cautionary notes is you don’t want to take much metal off the half cock notch all at once. Best to take it off a little at a time and keep checking as you don’t want to cut so much off that the sear nose won’t hold in the half cock notch. I prefer to check it BEFORE you put the mainspring back on while doing this work.

I do that by putting just the tumbler in the hole in the lock plate (without the tumbler being attached to the hammer) and the Sear and Sear screw in place. Then I place the sear nose in the full cock notch while holding the tumbler with my left hand. With my right hand, I move the sear just enough so it falls free of the full cock notch and hold it in that position. Then I rotate the tumbler with my left hand to see if the sear hits the half cock notch as it rotates past the sear. This is a good way to “gage” how much material you are taking off the half cock notch as your work progresses.

While you do this kind of work, you will be disassembling and reassembling the lock many times to see if you got everything corrected, so don’t be surprised that it is necessary.

You will need a mainspring vise, if you don’t have one. The following is the least expensive one that will work on your lock. https://www.trackofthewolf.com/Categories/PartDetail.aspx/1038/1/TOOL-VISE

However, that vise is too large for some civilian locks, so if you have more rifles or smoothbores, then I would advise buying one like this to use on the Cook and Brothers lock and all other locks. https://www.trackofthewolf.com/Categories/PartDetail.aspx/1038/1/TOOL-VISE-DX

If you have more questions, please ask.

Gus

 

[snubnose57]

Thanks, it appears that I will half to modify the half cock . with the sear and bridle screws loosened a little, it still catches at half cock.
Most times, it never fully engages the half cock notch, just catches on the tip.

 

[Artificer]

Thanks, it appears that I will half to modify the half cock . with the sear and bridle screws loosened a little, it still catches at half cock.
Most times, it never fully engages the half cock notch, just catches on the tip.

OK, glad you found that out. Also, make sure not to leave sharp edges each and every time you take metal off the half cock notch and before you assemble the lock to check it. A stone is usually best to do that, but it can be done with fine files or even judicious use of Emory Cloth (sand paper for metal). I have seen sharp edges snag and damage a sear nose.

After you get the sear to stop catching on the half cock notch outside the stock, let us know if it does it again in the stock, as that is caused by different things.

Gus

 

[snubnose57]

Thanks everyone!! Will work on it in a day or two, and report back.

 

[Artificer]

A few more things”¦..

A very important “sharp edge” to get rid of when filing down the sear notch is the new sharp edge or burr that is inside the notch, because you filed the notch down and wind up leaving a sharp edge or burr there. That burr or sharp edge must be removed before you try the lock to see if it is still catching in the half cock notch. I forget to do that one time early in my career working on these locks and that sharp interior edge “ate” or dug into the sear face when I placed the hammer in the half cock position and ruined the sear.

Something Zonie mentioned is very important about making sure you press the trigger and keep pressure/pressing on it well after the shot is fired. (This will ensure the sear nose stays clear of the half cock notch, once you file it down a bit.) However, I ran across a bunch of shooters who had either been used to set triggers which didn’t require keeping pressure on the trigger OR had been taught differently in other shooting disciplines. Folks who came to shoot UnCivil War Muskets from the ranks of Collegiate .22 rimfire and International BB gun shooting, were taught to “get off” the trigger as soon as the sear released and for them, the hammer on a Musket would catch on the half cock notch somewhat to very frequently.

What I wound up having to do on the Half Cock Notch for them was something I finally did as standard practice when filing the half cock notch down on Musket “Match Triggers.” I filed the outer edge of the half cock notch until the sear nose would clear the half cock notch when it was barely past the point it cleared the full cock notch. HOWEVER, that also required serious cutting into the Tumbler and modifying the half cock notch so it would hold at half cock. That is not easy to do as you don’t want to open/modify the half cock notch so much that the hammer rests too close to the nipple at half cock, where you can’t put a cap between the nipple and hammer.

Now I don’t think you will run into needing to do this, as long as you are careful about how much you file the half cock notch down enough, that continued pressure on the trigger will keep the nose of the sear from hitting the half cock notch. However, I wanted to mention this in case you have to file the half cock notch down enough that the sear won’t stay in the half cock notch correctly. You may need to open up the half cock notch a bit and that is usually done with diamond needle files.

BTW, the correct test of the half cock notch on a Rifle Musket or Musket is to turn the gun barrel down and support the weight of the gun just by your trigger finger on the trigger (but not pressing the trigger). As long as the Hammer stays on Half Cock, it was and is considered serviceable/"good to go." That is how Civil War Ordnance Regulations said to test the Half Cock Notch. Matter of fact, in at least one original Ordnance Manual I read, it FORBADE people pushing or hammering on the hammer with their hand “to test the half cock notch,” because that was way too much force and almost always injurious to the parts. Unfortunately, there are people who are ignorant of this and bash on the hammer at half cock “to test” it and almost always harm the sear nose, half cock notch or both.

Gus

 

[snubnose57]

The original problem is that no matter how hard or fast I pull the trigger, it always catches at half cock. I have an Enfield carbine and a 1841, no problem with those. I believe surgery for Mr. Cook will proceed Saturday. The lock is really clean. so maybe just a simple cleaning may do.

 

[Zonie]

I don't know if you have disassembled a side lock so assuming you haven't I'll give a brief description of what is involved.

You will need screw drivers that fit the slots on the screws so you don't booger the slots up.

It is best to have a main-spring vise to hold the mainspring in its compressed or flexed position. Some have used locking pliers like Vise Grips® successfully. Some not so successfully.


Remove the large screw that holds the hammer onto the tumbler.

Without trying to remove the hammer, bring the lock to the full cock position. This will compress/flex the mainspring.

Place the mainspring vise onto the spring so its pads will clamp on the spring close to the open ends (away from the front bend). (You won't be able to clamp the lower spring close to the tumbler but try to locate the vise/pliers as close as you can).
Do not try to squeeze or compress the mainspring with the pliers or mainspring vise.
You just want it to be snug so it doesn't slip off without adding any additional pressure to flexing the spring.

Some locks have a stirrup that hooks into the mainspring and on to a claw on the front of the tumbler.
If your lock has this, first notice that these are usually not symmetrical. They have a curved shape to them and they will not work if they are reinstalled backwards. Take a digital photo of it while it is still installed or make a sketch of it on some paper.
Pay special attention to whether the lower part is going forward or backward where it connects to the mainspring.

Like I said, the stirrup will only work if it is installed the right way.

Push the sear arm up to release the tumbler/hammer and rotate the hammer forward.
This will release all of the tension from the mainspring, leaving it compressed or flexed.

Gently rotate the vise/pliers and mainspring to pull the mainspring pin out of the lockplate.
DO NOT release the vise/pliers.
You want it to remain compressed or flexed. Carefully set the vise/pliers and mainspring to the side, out of the way.

Remove the sear spring, sear and tumbler bridle if one is over the tumbler.

Double check to see if the lock has a fly. It will be located next to the half cock notch.
If it has a fly, notice how it is installed, remove it and place it on a piece of masking tape so it doesn't get lost.

Do NOT try to pry the hammer off of the square tumbler drive.

Using a regular vise or two small blocks of wood, place the lock with the tumbler hanging down between the vise jaws or the blocks of wood.

You want the tumbler to be hanging freely in space with the vise jaws or blocks of wood supporting the lock plate on both sides of the tumbler so if your using a vise, do not clamp it on the tumbler.

Get something like a round metal bar or a punch with a large end that is smaller than the square hammer drive on the tumbler. (A large screw driver has been used by some).

Place the bar onto the square drive and lightly tap it with a small hammer or block of wood to drive the square out of the hammer (which is resting on the outer face of the lock).

The tumbler will fall freely after the square drive disengages from the hammer. Don't lose it. :grin:

After the tumbler is removed, do your thing with it.

Reassembling the lock is pretty much just the reverse of taking it apart but before you try tapping the hammer back onto the square drive, triple check it's position by rotating the partially assembled hammer/tumbler thru its full stroke paying attention to the way the tumbler rotates. It is surprisingly easy to get the hammer in a position that will cause the tumbler to be 90° from where it needs to be to work with the sear and mainspring.

Have fun.

 

[Artificer]

Good post, Zonie, :thumbsup:

"Some locks have a stirrup that hooks into the mainspring and on to a claw on the front of the tumbler.
If your lock has this, first notice that these are usually not symmetrical. They have a curved shape to them and they will not work if they are reinstalled backwards. Take a digital photo of it while it is still installed or make a sketch of it on some paper.
Pay special attention to whether the lower part is going forward or backward where it connects to the mainspring.

Like I said, the stirrup will only work if it is installed the right way."

This is why I earlier suggested the OP mark the stirrup as it sits in the lock before disassembly. If the Lady of the house has an old or almost empty bottle of finger nail polish she no longer wants, a drop of that polish near the bottom of the stirrup (as it sits in the lock) will show one quite easily which side faces away from the lock plate and in the correct vertical position. The stirrup could also be marked with a magic marker or even chalk.

Gus

 

[snubnose57]

Took the lock apart today. Filed a little, reassembled, no luck yet. While using my Enfield lock as a guide, I noticed something. The Enfield sear spring is a straight V, but the Cook sear spring looks as if someone squeezed the sear spring in the middle. The bottom leg of the spring has a small hump in the middle, not straight at all. Will order a new spring to see if that is the culprit.

 

[Zonie]

The only thing that spring does it to push the sear against the tumbler when the trigger is not pulled.

When the trigger is pulled, the trigger pushes the sear nose away from the tumbler and its pressure over-rides any force the sear spring has.

The sear spring is not the culprit so, save your money.

I did have another thought about what could be causing the problem.

If the trigger group is not installed deeply enough, it may not be pushing the sear far enough to clear the tumbler body and the half cock notch.

I can envision a case where the trigger moves the sear just far enough to disengage it from the full cock notch but no more. This would leave the nose of the sear riding just slightly above the body of the tumbler.

The half cock notch entry should be slightly below the surface of the area of the tumbler below the full cock notch but I suspect yours is not.

Perhaps removing a little wood under the trigger plate so it can be installed deeper in the stock might solve your guns problem? (It shouldn't take much wood removal.)

 

[snubnose57]

The half cock notch is below the full cock notch, protruding slightly out on the tumbler. Wish I hade a teenager here so I could post pictures.

 

[snubnose57]

Was going to try to inlet the trigger, but having no luck removing the trigger guard. Removed the 2 screws, but the front will not budge. The internet shows a pin to drift out, but I see nothing. Maybe the carbine is different?

 

[snubnose57]

Found the pin , trigger guard off. Will post results as I work on this. Once again, thanks for everyone's help, all replies appreciated.

 

[Artificer]

The only thing that spring does it to push the sear against the tumbler when the trigger is not pulled.

When the trigger is pulled, the trigger pushes the sear nose away from the tumbler and its pressure over-rides any force the sear spring has.

The sear spring is not the culprit so, save your money.

I did have another thought about what could be causing the problem.

If the trigger group is not installed deeply enough, it may not be pushing the sear far enough to clear the tumbler body and the half cock notch.

I can envision a case where the trigger moves the sear just far enough to disengage it from the full cock notch but no more. This would leave the nose of the sear riding just slightly above the body of the tumbler.

The half cock notch entry should be slightly below the surface of the area of the tumbler below the full cock notch but I suspect yours is not.

Perhaps removing a little wood under the trigger plate so it can be installed deeper in the stock might solve your guns problem? (It shouldn't take much wood removal.)

Zonie,

Though what you suggest is certainly conceivable, I have worked a lot of EuroArms Civil War guns over the years and never ran across that.

Normally, the Sear Tail provides plenty of pressure on the top of the trigger to keep the trigger forward and under tension when the trigger is at rest. This means normally the trigger will force the Sear Tail up far enough the nose of the Sear will clear the Half Cock Notch or at least come close. I would think the trigger would be loose for a bit at the start of the pull before it is under tension, if the trigger is inlet too far away from the Sear Tail. Hope what I am trying to describe is clear?

What I think is going on inside the stock is the top or possibly sides of the Sear Tail is hitting wood inside the lock mortise and that doesn't allow the Sear to go high enough to clear the Half Cock notch. Now that I have seen plenty of times in EuroArms or other repro UnCivil War guns. What one can do to check for that is candle "smoke" the tail of the sear or coat it in grease, try working the lock a couple of times in the stock and then seeing if the soot or grease shows up hitting the wood inside the lock mortise. Where the soot or grease shows a mark, the wood needs cleared some more to allow the sear tail to go high enough. I would also smoke or grease the lower mainspring leaf and around the claws/bottom of the rear of the leaf, including the bottom of the Stirrup, the Mainspring and/or Stirrup might also be rubbing and wood needs to be relieved for their free movement.

Something else I would look for is if there is a small/tiny ding/rub mark on the inside bottom of the trigger guard bow - meaning the bottom of the trigger is rubbing and not allowing the trigger to push up high enough on the sear tail when needed. Shortening the bottom of the trigger normally about 1/16", left enough room where it didn't contact the bottom of the trigger guard bow.

Gus

 

[Artificer]

I also have been wondering if maybe someone heated and bent the Sear behind the boss, so the tail of the sear would go no lower than the bottom of the lock plate with the sear engaged in either half cock or more usually full cock? This may not be readily apparent to someone who is not used to looking at internal musket parts.

So I found the below linked photo of original Enfield Sears and the center image in the photo shows how straight the sear is tapered down towards the Sear Leg. If that section is bent upwards too far, then that could easily cause the problem of the trigger not being able to lift the sear tail high enough for the sear nose to clear the half cock notch.
https://www.peterdyson.co.uk/acatalog/1998%20+%20800.JPG

Over the years, I had to bend a few rear of the sears to keep the sear leg above the bottom of the lock plate when the sear nose was in one of the notches. However, I bent them just enough to clear the bottom of the lock plate, so I didn't run into the problem of the trigger not being able to push the sear leg high enough for the sear face to clear the half cock notch.

This is just something else I thought may be happening and with no photo's to go from, it is just something else to check.

Gus

 

[Artificer]

Took the lock apart today. Filed a little, reassembled, no luck yet.

Snubnose,

How much did you file down the half cock notch from the original outer edge?

FWIW, I found in many of these locks I worked on over the years that I had to reduce the outer edge of the half cock notch by about 1/4 of the distance in some cases.

In extreme cases, I had to go further than that, but that also required reshaping the interior of the half cock notch so the sear would stay in the half cock notch when tested by supporting the musket muzzle down on the trigger finger and the Hammer set on Half Cock.

Was curious to see if you had made any progress?

Gus

 

[snubnose57]

Before I read the post, I ordered a new sear spring. I stopped filing on the half cock notch when I realized the sear spring was altered. Thought I would just wait for the new spring to arrive, then start on the problem anew with these new suggestions.