Spring making question

[MasterPython]

I have been planning to build a flintlock gun for some time and have started gathering materials. I have a peice of 4140 steel .045" thick about a half inch wide andabout four feet long. Would this be tick enough to make springs? And since it is alloyed do I have any chance of heat treating it without a tempering oven?

 

[tiriaq]

I don't think that 4140 would be a good choice for springs. You could cut off a piece, and try hardening and tempering it, as an experiment. I know that servicable springs have been cast from 6150. Had it done about 35 years ago, the springs are still working. Brownells, I think Dixie, sell annealed spring steel.
.045" is too thin for any spring on a flintlock with the exception of the sear spring, assuming that the 4140 will spring temper.

 

[charlesross]

1095 is a very good material to make a spring out of if you can new material in small quantities. Another good choice is to salvage an old spring. Forge it to shape, or grind it, and then heat treating begins....

Heat the spring uniformly to critical temperature (a magnet will not stick to it) and let it cool as slowly as possible - a pail of vermiculite is handy for that. Once your peice has cooled, heat it uniformly again and harden by cooling it rapidly. Depending on the mass, the quench medium takes some trail and error. Air is fast enough for some small pieces, oil is faster, water faster still. After hardening reheat the piece gently to achieve a temper. The oxide colours that form an the surface are a pretty good thermometer for that.

There's the quick lesson - get ten or twenty years of practise and you'll be an expert. Lots of trial and error involved.

Build a man a fire and he'll be warm for the night.
Set a man on fire and he'll be warm for the rest of his life.

 

[Intrepid]

1095 is a very good material to make a spring out of if you can new material in small quantities. Another good choice is to salvage an old spring. Forge it to shape, or grind it, and then heat treating begins....

Salvaged as in, say, a leaf spring out of a small car? I thought most leaf springs were 4130 or 5160?
I, too, have been dreaming about building a custom flinter for a number of years now. I have a (old and near worn out!) VHS copy of the Colonial Williamsburg Gunsmith video, and it is quite fascinating!
I've been stockpiling scrap brass for quite a while, and all I need is a silicon carbide (not cheap!) crucible to start casting some brass. Oh yeah, guess I need to make some patterns, too


Cheers,

Jim

 

[tiriaq]

A tempering trick that I have used successfully is to place the hardened spring in a little steel pan - sardine tins used to be steel - and add animal fat. I used lamb fat. Heat the pan until the fat is burning, keep the spring wet with melted, burning fat. When the fat burns off, the spring will be tempered. Do this outside. Tempering a mainspring by watching oxidation colours is difficult because of the size of the spring, and the varying thickness.

 

[rlg]

see this post as well

I have been planning to build a flintlock gun for some time and have started gathering materials. I have a peice of 4140 steel .045" thick about a half inch wide andabout four feet long. Would this be tick enough to make springs? And since it is alloyed do I have any chance of heat treating it without a tempering oven?

See this thread as well for more options and contacts.

http://www.canadiangunnutz.com/forum/showthread.php?t=125413

Good luck
Robert

 

[Waba]

I have used a number of materials successfully over the years for leaf springs, from old files to storebought o-1, and I could go on for some length on spring design and building.

I have a (old and near worn out!) VHS copy of the Colonial Williamsburg Gunsmith video, and it is quite fascinating!

If that is the film I saw in 1968/9 then it is the one that gave me the key to uniform tempering---the lead bath.I keep a frying pan full of lead alloy( loosely approximating Lyman #2) for springs. Lay the hardened spring on the lead. Melt the lead.Immerse the spring. When the lead no longer sticks to the spring let the spring air cool. Thicker sections need a bit longer immersion time but just remember that the temp of the lead will climb too high if you don't watch it.

 

[Cocked&Locked]

don't use 4140, it won't hold spring temper for long in that sort of application. The rest of the advice posted here is good, so I won't add more to it.

 

[10x]

Dixie Gunworks Sells spring stock to make flat springs. It is untempered.
You can cut this stuff with a hacksaw, file, or dremel to the proper shape, polish it to get ride of nicks and gouges. A spring will eventually break on a nick or a gouge. Draw out the final shape you want to bend it to, Use tempered nails to creat bending jigs. Heat the spring to a dark cherry red, bend it to the proper shaper, quench in oil.
After cool polish and to get rid of nicks and burrs.
Then use the burning vegetable oil, or hot lead method to draw the temper and cool the spring slowly. Then do a final polish and install the spring.

I have retempered "soft" springs for muzzle loaders in this manner and have gotten excellent results.
Buy a bag of coil springs and practice. They start out as springs, anneal them, bend them to shape, then temper, and draw the temper. Eventually you will get the process down so you get good serviceable springs.
The finer the material, the harder it is to cool slowly and get a good spring.

 

[mooncoon]

I have made at least 40 mainsprings, mostly V type. I use 3/8 drill rod and hammer it to approximate thickness then anneal , grind the surface scale off and file to final dimension. To temper, I heat to red hot, quench in water, then draw to spring temper by putting it in a shallow tin tray more or less covered with old automotive lube oil. Heat the oil and let it burn away and voila you have a spring. I support the spring slightly off the bottom of the tray by sitting it on 2 finishing nails about 1 1/2" long
I think drill rod is somewhere around 1095. I also have used a lead bath and high temp thermometer but the burning oil is far easier and very dependable. Most flintlock mainsprings are roughly .1" at their thickest point and taper to about .070 closest to the tumbler.

cheers mooncoon