Fixing Locks

[dave_person]

Hi Guys,
My apprentice, Maria, is the armorer for Warner's Extra-Continental Regiment, the Green Mountain Boys. After last weekend's event at Ethan Allen's homestead, she brought back repair work to the shop. A lock from a well used Miroku Brown Bess was tired and the frizzen loose and floppy. The trigger pull on the musket was a spongy 10 pounds. The next gun was an India made fusil de chasse that had a horrendously heavy trigger pull and simply did not spark or shoot very well. The third project was an India-made long land Brown Bess that also had a horrendous trigger pull and did not work very well. The owners all wanted to get the guns working before the Battle of Hubbardton event next weekend. It is instructive that the only gun still working flawlessly during tactical demonstrations on the final day of the event was Maria's fowler with a tuned high quality lock. Flintlocks are systems, meaning you can rarely correct one thing because when you do, you have to adjust or correct several more. Anyway, the Miroku lock was the best of the bunch but it needed help. One of the most serious issues is the half cock notch sticks out much further than the full cock notch.

What that means is you cannot lighten the trigger pull very much because it is that trigger pull pressure that keeps the sear out of the half cock notch when the lock is fired. With a light trigger squeeze, the sear will easily drop back into the half cock notch when firing. This is the reason why set triggers require locks with fly detents. This Miroku lock cannot possibly work with a light trigger. We will take care of that by grinding down the lip of the halfcock notch and reconfiguring the tumbler notches as best we can. We welded steel on the sides of the toe of the worn frizzen to make it fit precisely into the slot between the lock plate and pan bridle. I made a new frizzen pivot screw that fits precisely. One reason for the mushy trigger pull was the hole for the sear screw was too large for the screw and the sear and bridle moved under pressure. We solved that by making a new sear screw on which there was a larger shoulder that fit in the bridle hole, then narrowed to fit the sear precisely, then narrowed again to make a shoulder for the threads so it tightened against the lock plate without pinching the bridle and sear. Everything fit well after our modifications and the components we changed are to be case hardened and tempered.

Now the other two projects. I am going to stop any narrative and just show photos. I am not sure what we will do to fix these problems. The first is the Bess and the second is the fusil.

dave

 

[Hatchet-Jack]

Excellent post Dave! It's neat that you are able to help the regiment by repairing their arms just as gunsmiths did in colonial times.

 

[ArmorerRoy]

Hi Guys,
My apprentice, Maria, is the armorer for Warner's Extra-Continental Regiment, the Green Mountain Boys. After last weekend's event at Ethan Allen's homestead, she brought back repair work to the shop. A lock from a well used Miroku Brown Bess was tired and the frizzen loose and floppy. The trigger pull on the musket was a spongy 10 pounds. The next gun was an India made fusil de chasse that had a horrendously heavy trigger pull and simply did not spark or shoot very well. The third project was an India-made long land Brown Bess that also had a horrendous trigger pull and did not work very well. The owners all wanted to get the guns working before the Battle of Hubbardton event next weekend. It is instructive that the only gun still working flawlessly during tactical demonstrations on the final day of the event was Maria's fowler with a tuned high quality lock. Flintlocks are systems, meaning you can rarely correct one thing because when you do, you have to adjust or correct several more. Anyway, the Miroku lock was the best of the bunch but it needed help. One of the most serious issues is the half cock notch sticks out much further than the full cock notch.

What that means is you cannot lighten the trigger pull very much because it is that trigger pull pressure that keeps the sear out of the half cock notch when the lock is fired. With a light trigger squeeze, the sear will easily drop back into the half cock notch when firing. This is the reason why set triggers require locks with fly detents. This Miroku lock cannot possibly work with a light trigger. We will take care of that by grinding down the lip of the halfcock notch and reconfiguring the tumbler notches as best we can. We welded steel on the sides of the toe of the worn frizzen to make it fit precisely into the slot between the lock plate and pan bridle. I made a new frizzen pivot screw that fits precisely. One reason for the mushy trigger pull was the hole for the sear screw was too large for the screw and the sear and bridle moved under pressure. We solved that by making a new sear screw on which there was a larger shoulder that fit in the bridle hole, then narrowed to fit the sear precisely, then narrowed again to make a shoulder for the threads so it tightened against the lock plate without pinching the bridle and sear. Everything fit well after our modifications and the components we changed are to be case hardened and tempered.

Now the other two projects. I am going to stop any narrative and just show photos. I am not sure what we will do to fix these problems. The first is the Bess and the second is the fusil.

dave

That is great info. Thanks

 

[Dutch7]

“I am going to stop any narrative and just show photos. I am not sure what we will do to fix these problems.”

I am certain you and the apprentice can repair these but a welder will be required

 

[dave_person]

Hi Dutch7,
A welder and a bushing in the tumbler hole. Here are some other photos od the India-made guns. I think the lock mortises were inlet using a dull screw driver.

Look at the lock plates. They were probably file shaped and then polished using wheels. See how the screw holes are dished out and so is are the tumbler holes.

On both cases, if the tumbler holes were not dished out by polishing, the flintcocks would not clear the lock plates when seated on the tumblers. They would tighten against the lock plates. Here are some more photos of the stocks.

My apprentice is learning quickly why I don't usually waste my time on this stuff.

dave

 

[Notchy Bob]

Dave, these posts are great. Very instructive. The work you and Maria do in your shop is way over my level of skill, but I like knowing how to diagnose the problems, and what can be done to fix them even if I'm not equipped to do it myself.

The comments and photos of the half cock issue on the Miroku were particularly informative. I have an original I. Johnson M1842 percussion pistol that's in good condition overall, and the barrel has been lined by Mr. Hoyt, but it has about a 90 pound trigger pull. Seriously, I have to use both index fingers and both middle fingers to pull the trigger. I called Brad Emig about it, and he described pretty much what you showed with the Miroku lock... The trigger can't be lightened too much because of the geometry of the tumbler, although he said he could improve it from its current level of function.

I look forward to additional posts on this thread. It is very instructive.

Thanks!

Notchy Bob

 

[FlinterNick]

Hi Guys,
My apprentice, Maria, is the armorer for Warner's Extra-Continental Regiment, the Green Mountain Boys. After last weekend's event at Ethan Allen's homestead, she brought back repair work to the shop. A lock from a well used Miroku Brown Bess was tired and the frizzen loose and floppy. The trigger pull on the musket was a spongy 10 pounds. The next gun was an India made fusil de chasse that had a horrendously heavy trigger pull and simply did not spark or shoot very well. The third project was an India-made long land Brown Bess that also had a horrendous trigger pull and did not work very well. The owners all wanted to get the guns working before the Battle of Hubbardton event next weekend. It is instructive that the only gun still working flawlessly during tactical demonstrations on the final day of the event was Maria's fowler with a tuned high quality lock. Flintlocks are systems, meaning you can rarely correct one thing because when you do, you have to adjust or correct several more. Anyway, the Miroku lock was the best of the bunch but it needed help. One of the most serious issues is the half cock notch sticks out much further than the full cock notch.

What that means is you cannot lighten the trigger pull very much because it is that trigger pull pressure that keeps the sear out of the half cock notch when the lock is fired. With a light trigger squeeze, the sear will easily drop back into the half cock notch when firing. This is the reason why set triggers require locks with fly detents. This Miroku lock cannot possibly work with a light trigger. We will take care of that by grinding down the lip of the halfcock notch and reconfiguring the tumbler notches as best we can. We welded steel on the sides of the toe of the worn frizzen to make it fit precisely into the slot between the lock plate and pan bridle. I made a new frizzen pivot screw that fits precisely. One reason for the mushy trigger pull was the hole for the sear screw was too large for the screw and the sear and bridle moved under pressure. We solved that by making a new sear screw on which there was a larger shoulder that fit in the bridle hole, then narrowed to fit the sear precisely, then narrowed again to make a shoulder for the threads so it tightened against the lock plate without pinching the bridle and sear. Everything fit well after our modifications and the components we changed are to be case hardened and tempered.

Now the other two projects. I am going to stop any narrative and just show photos. I am not sure what we will do to fix these problems. The first is the Bess and the second is the fusil.

dave

I had the same issue on a Japanese bess lock recently, I made a bushing from mild steel and welded it in. The bushing was just a few thousands tighter, tight enough to ream in place with the rehardened tumbler. I had used my hand drill to turn it through slowely, lubricated with cutting oil. Oddly though … the lock didn’t seem very used, I’m wondering if it was just over drilled and not worn open. Springs I lighted up out to an even balance to keep the issue from happening again then i case hardened the plate, which i think is some type of mild alloy, possibly 8620 steel. It’s very mild.

A lot of this I’ve learned from observing your work Dave, thanks very much, always.

 

[Dutch7]

“My apprentice is learning quickly why I don't usually waste my time on this stuff”

She will learn this quickly too, I hope

 

[waksupi]

The triggers can be improved by pinning them higher rather than through the trigger plate. This can require making a new trigger. Using magnifiers and diamond stones the engagement surfaces can be smoothed. A bit of good anti-seize grease on the tumbler/sear engagement on re-assembly will cut the trigger pull in half or more. Fixed lots of guns like this over the years. It also seems to deal with the odd tumbler dimensions, too.

 

[sturmkatze]

My apprentice is learning quickly why I don't usually waste my time on this stuff.

dave

Certainly those triggergaurds have more detail to the acorn than my pedersoli. I looked at a brand new one and it was all smoothed out.

 

[FlinterNick]

Certainly those triggergaurds have more detail to the acorn than my pedersoli. I looked at a brand new one and it was all smoothed out.

The Indian trigger guard is not shaped correctly. The Acorn leaves are much less robust and often have to be cut with a graver, they’re not usually casted in. A pedersoli guard has the right ‘Basic’ shape, it just needs to be cut correctly.

 

[Rifleman1776]

Now........somebody explain to us why they think a fix-it job like that should be cheap.
Great tut, Dave.

 

[FlinterNick]

Now........somebody explain to us why they think a fix-it job like that should be cheap.
Great tut, Dave.

I suppose it depends what they’re driving … you ought not charge 100% what the lock may be worth. Indian repairs don’t yield much

 

[BackDraft]

I haven’t even read everything posted here yet. I just saw the magic 3 words, “My apprentice Maria”, and I clicked the ‘watch’ button. I knew it would be enlightening, and entertaining.

 

[AwwNaww]

Thank you much for the detailed analysis of these issues. If I wanted to buy a Brown Bess replica, whose should I buy? The problems above are really sad.

 

[BadDaditood]

I have heard that Loyalist Arms ships a product that works out of the box.
My experience with a balky lock from our frosty friends north of the border is not pleasant, and as yet unresolved.
Same oversized holes in gouged out lock plate and octagonal barrel polished so hard it’s almost round.
At this point the money I thought I was saving is irrelevant.

(Sorry to butt in if you were asking Dave)

 

[AwwNaww]

Thank you much...I'll look to Loyalist Arms

 

[dave_person]

Thank you much for the detailed analysis of these issues. If I wanted to buy a Brown Bess replica, whose should I buy? The problems above are really sad.

Hi AwwNaww,
I am afraid I don't have a good answer for you with respect to Brown Bess. The Pedersoli and Miroku usually are the best of the lot but they leave a lot to be desired both from historical accuracy and function. The India-made guns are a gamble. Some may work adequately but some are real lemons and very poorly made. The Miroku version of the French model 1766/68 is the best commercially reproduced 18th century musket you can find. They did an excellent job producing it. Their Bess, not so much. One problem with Miroku is their castings were superb and the alloys excellent but they did no finish work on those parts. They basically assembled the cast parts as is with minimal machine fitting. So a Miroku lock can be turned into a superbly functioning lock if you treat it as a partially finished kit lock. The Pedersoli components are also good, not quite up to the Japanese stuff, but a Pedersoli BB lock can be transformed into a good and much more authentic lock. The India stuff is sometimes OK but more often terrible. I usually don't accept jobs working on them. It is just too labor intensive and the end result rarely satisfies. Unfortunately, the only way to obtain a properly functioning and historically accurate Brown Bess is to have one made from TRS parts by someone who knows Brown Besses. That is a very unsatisfying answer but there it is.

dave

 

[dave_person]

Hi,
Well I fixed the Miroku Bess lock this weekend. It is now a very good lock and might actually pass 18th century British ordnance inspection, something none of the modern repros would do in any way. The tumbler screw securing the flintcock was badly corroded and could not be loosened. The slot was badly mauled from folks trying to do that. I used penetrating oil and heat but nothing worked and the screw had to be replaced anyway, so I ground off the head. Unfortunately, the tumbler and cock had corroded together and I could not remove the tumbler. We soaked it in penetrating oil for 3 days and tried again using heat. No go. I used a ball peen hammer and steel punch and it was not enough. I heated the tumbler and cock then applied penetrating oil and let it sit over night. The next day, I pounded out the tumbler with a punch and a 5lbs hand sledge hammer. I beat the living $&!# out of it. It finally worked and the parts showed worse the wear. I annealed all the parts in my heat treating oven so I could work on them.

I filed down the lip of the half cock notch but could not reduce its height to be below the lip of the full cock notch. That means the final trigger pull cannot be too light. It will need to be at least 3.5-4lbs. That will be fine for a reenactor and far, far better than the owner has experienced. To aid that effort, I ground the lower leaf of the sear spring thinner to weaken it. That was the key solution. Next, I needed to fix the sear. The hole in the bridle was larger than the hole in the sear.

As a result, the sear moved up a little when the trigger was pulled resulting in a mushy trigger pull. I solved that by turning a new sear screw that had a shoulder for the bridle, then reduced to fit the sear precisely and then reduced again to make shouldered threads.

That solved the problem entirely. I also had to make a new frizzen pivot screw for the same reason. The hole in the pan bridle was larger that the hole in the frizzen. In addition, the thickness of metal on the pan bridle on top of the hole for the frizzen was paper thin. I gas welded new metal on top to strengthen it and am proud to report that I did not burn through the thin metal. I think I could actually weld a beer can. I also welded steel on the sides of the frizzen toe to eliminate the terrible side to side play that was there.

After that, I made a new frizzen pivot screw that fits the holes precisely.

I flattened and polished the inside of the lock plate. Polished all the internal components. I fitted a new tumbler screw. Cleaned up the exterior, reshaped the feather spring to put more pressure on the frizzen, hardened and tempered it. Then I case hardened and tempered the lock plate, frizzen, sear, tumbler, and bridle. I polished off the case colors and tarnished the lock to look used. Finally, the frizzen needed a new sole. I made one from high carbon steel and soldered it to the frizzen using Stay Bright low temp silver bearing solder. I cut the sole out of the steel, roughly shape it and give it a curve to match the face of the frizzen. I give it a little more crescent curve than I need because during hardening and quenching, the curve may straighten a little. I heated it bright red, quenched in warm water and then fluxed and tinned the face of the frizzen. I fluxed and laid the sole on the frizzen and heating from below, melted the solder until the sole seated in place. Then I cooled it, and ground the edges flush. I heated the feather spring and opened the bend slightly then hardened and tempered it. I also weakened the main spring by grinding off thickness of the lower leaf and a large bevel on the side. Eventually, the force to bring the lock to full cock from rest was about 10 lbs and the force to open the frizzen was 4 lbs. Those are good parameters. I cleaned up the lock, assembled it and then tested everything. It is a good lock now. All the sparks into the pan where they do the most good.

dave

 

[PathfinderNC]

Fascinating work.