R. E. Davis Jaeger lock modifications

I have recently received an up graded hammer for my R. E. Davis Jaeger lock. I looked at the Chambers Early Christian Spring lock on the TOW web site. I am thinking the Frizzen from that lock could be installed on the Davis lock with little modification. It looks to have a better angle to receive a blow from the flint and start scraping from initial contact instead of receiving the blow straight in to its face. I need to do something with the original frizzen any way since it is all beat up and appears rather soft. I am also thinking of re-heat treating the original frizzen and at the same time bending it back a little. Has anyone tried any of these proposed changes?

 

[rich pierce]

There are lock fiddling things I will do and those I will not. I've built a number from kits and a couple from castings that were not kits and made a few springs. Early on I messed up a frizzen or two. It seemed to me in the late 70's that a lot of lock manufacturers were having trouble with getting good steel in their castings and so I did a fair amount of work tuning locks on guns I built and for others.

I'd not try to bend a frizzen. The probability of messing up the screw hole or that area where it will be drilled is too great. It would be different if working from an oversized rough forging but there's precious little extra metal on the teat that contacts the frizzen spring. Once it gets out of shape or twisted or the hole elongated or out of round or too big, the part is useless.

Swapping parts from different makers is usually not helpful. The one part was supposed to be designed for that lock, the other was not. The pans may be of entirely different shapes, the pivot bolt also, the distance from the bolt to the pan, the distance from the pivot to the fence, and the offset of the teat from the edge of the frizzen can all be different and make it nearly impossible to fit one to the other w/o welding etc.

There are several things you can do with the frizzen you have. #1 is to case-harden it, #2 is to "steel" it by riveting or brazing a piece of real steel to the face (common in colonial times). If you took some 1080 to 1095 steel and fitted it to the frizzen and brazed and quenched it, it would spark like a demon. Draw out the teat a little bit and grind it all back and you're good to go.

That frizzen is also pretty hefty so do not be afraid to grind it back to re-shape a little bit.

I built an early Christians Spring style gun using this lock back in 1982 or so and it required some serious tuning at that time. Once I got it tuned, it was fast and reliable and crisp as skim ice on a puddle.

 

[Birddog6]

Can you see a big difference in the hammer ?

Have you tried it to see if it corrects the lock problems :hmm: ?

 

[Zonie]

I wouldn't try bending it for the reasons mentioned above and because most likely it is a casting.

Castings have a very large grain structure and the bond between the grains is not real strong. Because the grains are large, they may extend a good percentage of the distance from one side of the frizzen to the other.
Put another way, it is likely to break if you try bending it very much, even if you anneal it.

Wrought or forged steel usually has very fine grains so they are not as likely to break, but there are very few locks made today with forged or wrought steel frizzens.

If the frizzen was making good sparks before, it IMO does not need to be rehardened. The washboard or grooves that were cut into it by the flint in the old cock can be removed by regrinding or sanding using course "wet/dry" silicone carbide paper (don't bother with "emery paper or cloth. Emery is very soft so IMO it doesn't work well).
IMO, the wet/dry paper method is better than a power grinder because power grinding can overheat the part and destroy it's hardness. It can also introduce Grind Burns and local sharp stress risers which may later cause failures.)

Another tool that can be used is a whet stone. Here again, because it is a hand operation it should not effect the hardness of the existing part.

If it were my lock, I would smooth out the frizzen and try the new cock. That may be enough to solve all of your problems. If it doesn't, you can always remove the frizzen later and harden it.
There are many posts that describe the hardening and tempering process.

 

[jerrywh]

I have bent dozens of frizzens be they cast or not. I just heat them red hot where I want to bend them and bend them. then when I get them where I want them I just case harden them again.
If you case harden a frizzen -don't forget to temper it .Put it in the oven for 1 hour at 350 to 400 deg. It should come out a real light straw color. Then draw the tail to a blue color.

 

[Dave K]

Jerry, what do you mean by drawing the "tail" to a blue color?

 

[Zonie]

Jerry, what do you mean by drawing the "tail" to a blue color?

I believe he is suggesting that the area around the frizzen screw should be softened a little more than the upright face of the frizzen.
This increases the toughness of the matrial so it is less likely to break.

Because you want to do this locally, it must be done with something that will heat just the area you want to retemper. I use a small pencil like propane torch who's flame can be directed only at the area I want to effect.
It is a good idea to shield the areas you don't want to retemper. This only requires something to keep the flame from hitting the protected area.

The reference to the color "blue" is a description of the color the metals surface will become.
If you ever took apart a old clock, you may have noticed the spring in it was a rich blue color. That is a good temper for springs and other items that must hard but very tough.

Briefly, when clean steel is heated, the surface changes color depending on how hot it is.
The first color you would see would be yellow, going to straw yellow, then to brown, then purple then blue. Beyond blue, it starts to turn a dull gray.
When heating the metal, care must be made to do it slowly and gently. The colors will appear and start changing fairly rapidly from one to the next. The difference in temperature between yellow and blue is only about 140 degrees F.

If I am doing this color tempering just to obtain a nice blue color for decorative purposes (screw heads look really pretty) I will quench the part in oil when the color is reached. By doing this, the surface has reached the correct temperature but the depth of the heated material may be rather shallow.

If I am tempering the part for strength (as you would be doing here), I just let the part air cool when it reaches the desired color. This allows the heat to penetrate the metal so that the whole area is tempered.

 

[jerrywh]

zonie is exactly correct.
If you don't the thin section between the pan cover and the tail is likely to break. The abrupt change in cross Section oF that part makes it especially vulnerable anyway.

 

[Stophel]

Let's try this again...

Here is a lock made from the Davis lock (this one is one of their supposed "french fusil" locks, but it is the same thing). The lockplate was reshaped to get rid of as much of that horrible banana shape as possible, the cock was reshaped so that the flint wouldn't hit the pan (even at half cock, the flint jaws were not horizontal, but slanted downward in a most unattractive manner), the bridle was worked so that the shoulder of the tumbler struck the bridle at the same time that the shoulder of the cock struck the top of the plate (I may or may not have had to make a new bridle to do this..I don't remember, but I often do have to make a new one), The mainspring was closed up at the "v" since, as it comes, it is sprung out WAY too much and has an absolutely incredible amount of "preload" on the spring. Even at half cock, it was bent backwards (look at the photos of this lock in the Track of the Wolf catalog and you'll see what I mean). The frizzen spring is one of the "blank" springs from Track. Other than filing and polishing, the frizzen was not messed with. It now sparks like wildfire.[url] http://photobucket.com/albums...cks/?action=view&current=7119170-R1-013-5.jpg[/url]

I have bent a few frizzens back if I thought they were too vertical.

Do not even DREAM of bending ANY lock part cold. It MUST be hot.

Davis "carbo-nitrides" their parts (a modern form of case hardening) which I like very much. The frizzen face should be rock hard. If you can't scratch it with the sharp point of a file, it is fine.

 

The Chambers Frizzen fit almost perfectly. It came heat treated. I used the knife sharpening wheel on my bench grinder to remove just enough of the bottom so it would close flush over the pan. It is shaped exactly as I thought it should be and sparks wonderfully. The only problem with its dimensions is it is about 1/32" too short from the pivot screw to the back edge to cover the pan completely. At least now I know how much I need to cant the original replacement Frizzen when I'm heating it to harden it :applause: