Lock building project

[mooncoon]

I traded for a jaeger style target rifle quite a few years ago with the intention of replacing the lock. The lock that came with the gun did not fit the mortice apart from being the ultimate bodged up afair. Photos below are of the gun and the new lock so far although I intend to redo several spots on it. If one learns from ones mistakes, I guess I must have learned a lot on this one. The frizzen and #### are store bought and I intend to replace the #### with one that is about 1/16 - 1/8" longer. The lower jaw on the present one strikes the fence on the pan. For reasons that escape me now, I located the pivot for the sear about 1/16" too low and intend to make a new sear although the present one works.
There were a couple of surprises; one is that the barrel is very wide at the breach end and I should have had the upper arm of the mains spring start farther forward as well as closer to the bottom of the lock. Because I made the mainspring like a that used in conventional locks and normal sized barrels, I had to grind away a lot of the top arm to make room for the barrel. What was very surprising is that I expected that to cause the upper arm to bulge when the the lower arm was bent up but it did not. I also made the forward portion of the tumbler similar in proportion to a most modern locks but I now realize that if I had made the forward arm a bit shorter and the lower arm of the main spring a bit longer, I could probably get more rotation (in an angular sense) on the tumbler for the same amount of movement of the mainspring.

cheers mooncoon

 

[Glenfilthie]

Good luck with that MC - it looks like you will have your work cut out for you...

 

[tiriaq]

What stops the foreward movement of the ####? Usually there is a shoulder on the inner surface of the #### which strikes the top of the lockplate, although some English sporting locks did use the chin of the lower jaw contacting the flashpan fence as a stop.

 

[englishman_ca]

Did you do this while squatting on the garage floor with just basic hand tools? I find that when I handmake fiddley parts, I often make three. The first one almost fits, the second fits but could be better and the third one is close to what I wanted. Sometimes I make a fourth cos I dropped one and loose it under the bench or if springgy, launch it accross the garage. Kudos to you for tackling such a project, it takes time, patience and good eye.

 

[mooncoon]

What stops the foreward movement of the ####? Usually there is a shoulder on the inner surface of the #### which strikes the top of the lockplate, although some English sporting locks did use the chin of the lower jaw contacting the flashpan fence as a stop.

at the moment it is the lower jaw of the #### because it is too short. With a proper ####, the top of the tumbler will stop against the top back of the bridle and I will also have a shoulder on the #### which will stop against the top of the lock plate. I thought of adding some material to this #### for the shoulder but it basically only has to last for 50 - 100 shots tops until I can get a new #### of the proper length.
I am hoping the gun is accurate and want it for a chunk gun shoot at Heffley Creek at the end of August and after that will have time to make some changes.

cheers mooncoon

 

[mooncoon]

Did you do this while squatting on the garage floor with just basic hand tools? I find that when I handmake fiddley parts, I often make three. The first one almost fits, the second fits but could be better and the third one is close to what I wanted. Sometimes I make a fourth cos I dropped one and loose it under the bench .

The lock plate is just scrap plate filed to fit the lock recess. The pan and its bridle are 1/2" plate with a slot milled in the bottom for the lock plate and some weld added to the back to make the fence, because I can use thinner stock to make the pan that way. The pan is silver soldered to the lock plate. The tumbler is 4140 round stock turned on the lathe to look sort of like a wheel and axel then shaped with files. The tumbler bridle is just flat plate milled into an L shape (ie to leave a pedestal that the screw goes through) then filed etc. Springs are drill rod forged to thickness. Screws are drill rod turned on the lathe. So far there is no 1/2 #### and detente (fly) because I need to get a small end mill and because I am in a rush to get the gun shooting.

I also have a gap in the space time continuum into which small parts sometimes are sucked, never to be seen again :>) :>) Perhaps if and when I get too old to putter in the basement and remove the clutter, I will find a small pile of small screws, springs and miscellaneous bit.

cheers mooncoon

 

[Intrepid]

Drill rod for springs...? O1 or W1? And what is the carbon content of drill rod, I can't remember...

Nice lookin' rifle!


Jim

 

[Ol' Flinter]

...makes a fella even more appreciative of the skills of the old-timers who could hammer out a complete flint lock and temper the parts with a crude forge!! Good luck at Heffley.

 

[mooncoon]

Drill rod for springs...? O1 or W1? And what is the carbon content of drill rod, I can't remember...

I think it is around 1095 and I normally quench in water because with something as thin as a spring, I can get away with it. On thicker things I often use about 3/8" or so of oil on top of water because the oil takes some of the shock off and the water does not burn or smoke the way an oil quench does. Until fairly recently I used the burning oil method of drawing the temper on mainsprings but the last three or four I switched and have been using my Lee lead pot heated to 720 F measured with a high temp thermometer. I did try making a very large mainspring using a piece of automotive leaf spring but I think it must have to be heated to 750 or 800 F because at 720 - 740 it is still too brittle
I use drill rod for making machine screws as well and it is certainly not free machining. Miserable stuff to turn in the lathe.

cheers mooncoon

 

[Intrepid]

Neat Thanks Mooncoon, I'm going to have to try it, and see how it goes.



Jim

I think it is around 1095 and I normally quench in water because with something as thin as a spring, I can get away with it. On thicker things I often use about 3/8" or so of oil on top of water because the oil takes some of the shock off and the water does not burn or smoke the way an oil quench does. Until fairly recently I used the burning oil method of drawing the temper on mainsprings but the last three or four I switched and have been using my Lee lead pot heated to 720 F measured with a high temp thermometer. I did try making a very large mainspring using a piece of automotive leaf spring but I think it must have to be heated to 750 or 800 F because at 720 - 740 it is still too brittle
I use drill rod for making machine screws as well and it is certainly not free machining. Miserable stuff to turn in the lathe.

cheers mooncoon

 

[mooncoon]

Neat I'm going to have to try it, and see how it goes.

Something to think about is the location of the lower arm of the spring. If its pivot point is near the bottom of the lock plate, the tip will not move towards the center of the tumbler. If you have the pivot of the lower arm up high, the tip moves in on the tumbler and you have to file space for it, closer to the axel of the tumbler,

Also when making the little tit on the upper arm and that goes into the lock plate just before the bend of the spring, leave a strip which you can then grind or file to fit after the spring is bent to its final shape.

final suggestion is that recently drill rod seems a lot more difficult to anneal after forging. I also think the scale on the surface is hard and dulls files. I bought one of those $40 angle grinders with a fine 4" disc on it and now grind a lot of the spring closer to final dimension (thickness) where I used to use files. I use the disc flat wise not on edge to do the grinding. Saves a lot of filing and a lot of files. I do my annealing in wood ash, by the way and for small parts clamp a couple of thick pieces of steel onto them so that they cool slower

cheers mooncoon

 

[Intrepid]

And thanks again

I, too, use an angle grinder with 'flap disks', or 'blending wheels' as some call them, for thinning stock as needed, then finish with either files, or emery cloth in various grades. It does indeed save a lot of grunt work with a file


Jim

Something to think about is the location of the lower arm of the spring. If its pivot point is near the bottom of the lock plate, the tip will not move towards the center of the tumbler. If you have the pivot of the lower arm up high, the tip moves in on the tumbler and you have to file space for it, closer to the axel of the tumbler,

Also when making the little tit on the upper arm and that goes into the lock plate just before the bend of the spring, leave a strip which you can then grind or file to fit after the spring is bent to its final shape.

final suggestion is that recently drill rod seems a lot more difficult to anneal after forging. I also think the scale on the surface is hard and dulls files. I bought one of those $40 angle grinders with a fine 4" disc on it and now grind a lot of the spring closer to final dimension (thickness) where I used to use files. I use the disc flat wise not on edge to do the grinding. Saves a lot of filing and a lot of files. I do my annealing in wood ash, by the way and for small parts clamp a couple of thick pieces of steel onto them so that they cool slower

cheers mooncoon

 

[H Wally]

Man - these threads are always lessons in gunsmithing. I hope it turns out well and shoots even better at Heffley!

 

[mooncoon]

I finally got around to attacking the lock again and seem to have improved it or at least made things a lot closer to the way that I should have the first time. I wanted to get more rotation out of the #### so I made a new main spring with the upper arm quite a bit thicker than the first one and more taper to the bottom arm to permit a bit more bend. Also welded up some of the screw holes as well as added weld to the arm of the tumbler bridle so that I could relocate the sear higher in the lock. Had to make a new better sear spring as well as relocate that. Altogether I am getting more rotation out of the #### which allows it more time to accelerate and the lock seems to be sparking better now. Also I was having considerable problems with the sear binding on the set trigger and that is now eliminated. All that is left now is to see what sort of accuracy I can get out of the gun.

current lock

As first made with the sear too low and not enough taper to the mainspring.

What is very strange about this gun is that something must have happened to the original chamber area because a previous owner has done a very good job of making a new extended breach plug with a long fine thread into the barrel. The original vent hole has been filled in and is covered on the inside by the threads of the breach plug. All of this has lengthened the barrel by about 1 1/4". Strangely however the vent hole when I got the gun was a long straight hole with no coning and when the gun did fire, it was with a long hang fire. I drilled this hole out and installed a vent liner which improved things tremendously. The last 10 or 12 inches of the forestock had been replaced and originally I thought that it had been broken. Later I realized that by lengthening the heavily swamped barrel, the first 3/4 of the barrel channel would have had to be widened slightly but the last portion would have been quite open as well as too short. The solution was to replace the last portion and re inlet. I would be most curious to meet the fellow who did the work and find out exactly why. I think someone else haywired up a lock to fill the hole and make the gun easier to sell. The haywiring on that lock was far too crude to have been done by the person who extended the breach portion.

cheers mooncoon