Making Springs

tactical870

tactical870

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Anyone here have experience making springs? I'm in need of a spring for the cocking arm on a Hopkins and Allen XL bulldog in .32rf. I went to a local machine shop today and got a piece of spring steel approximately .022" thick (similar to original) When I try to cut the material it takes a curl shape to one side and is no good. Also seems softer than the original material. Any sources for parts? Ideas for making a spring? Thanks
 
hi tac making springs is not that complicated but you need to know what you are doing.
my advice is buy one if you can but if you cant then here is a basic outline for you.

1 make the spring the size and width of the original as well as the same thickness of spring stock.

2 it must be hardened and drawn back to the desired temper.

3 to harden heat to a critical temperature and oil quench.

4 reheat to around 800 degrees dark blue colour(guess) and allow to cool

thats it now 800 degrees is a guess as spring steel varies by type but you can get a spec sheet from the machine shop where you get the spring stock which will tell you the makeup. then google the heat treat specs for that material and you will know for sure.
 
I make 5 or 10 V style mainsprings a year. I forge mine out of drill rod but as applies to you, don't worry about the curling or twisting; heat the material up red hot and hammer it straight. Toss the red hot material in a bucket of wood ash to anneal and when cool, brush gently on the grinder to remove the scale and then grind and file to dimension and finish with draw filing and a quick sanding with 150 grit abrasive paper using cutting oil
Once the spring is to dimension and the correct curve (bend hot) heat it red hot and quench in water with 1/4" of lube oil on the surface. Check that it is file hard then put it in a tray of lube oil, with the spring on edge and sitting on two 1 1/2" finishing nails. You will need a steel block with a slot in it to hold the spring on edge if it is a single leaf. Heat the oil with a torch until it flashes and let the oil burn away. When the oil is gone the temper is drawn to spring temper. If the oil does not want to burn try putting a piece of cloth in the oil as a wick and further it is sometimes necessary to add a small amount of 2 cycle oil.
While I used to draw the temper in molten lead using a thermometer, I find the burning oil is very consistent and dependable.

cheers mooncoon
 
Thanks for the advice. The spring I was attempting to make was approx .060" x .022" x 1" A little finer than what you guys are describing. The machine shop I got the sheet or spring steel from told me to cut it with tin snips but it seems to curl it to the side every time I cut it. I have the gun working for now but would much rather get a proper spring made for it. I am by no means a gunsmith, but I am a mechanic with a good working knowledge of this stuff. Thanks for all the advice.
 
Springs aren't cut out of sheet steel. Spring wire is wound on a mandrel then heat treated.
"...seems to curl..." You using aircraft snips? They come in left, right and straight. Still not how a spring is made though.
 
I'm making flat springs not coil springs. Had a good go at gas welding up some parts then case hardening tonight for an old .32 rimfire dictator..... Actually looks professionally done... LOL
 
tactical870 said:
Thanks for the advice. The spring I was attempting to make was approx .060" x .022" x 1" A little finer than what you guys are describing.
Click to expand...

The principles are the same however. shape the spring then temper hard and draw the temper to a working hardness. With such a small spring you do not need oil on the surface of the water when hardening but the burning oil for drawing the temper is very dependable, at least for me

cheers mooncoon
 
tactical870 said:
I'm making flat springs not coil springs. Had a good go at gas welding up some parts then case hardening tonight for an old .32 rimfire dictator..... Actually looks professionally done... LOL
Click to expand...
i keep an assortment of rewind springs from various
smal gas engins. eg, lawn mowers, gas weed eaters,
chain saws,outboards,ect,
also another source is the shipping banding and the real
heavy banding that is used in the sawmills. all this stuff
is already heat treated and handy for various flat springs.
 
Hell of an idea. I just realized the banding that our new outboards come shipped with is very close in thickness to what I need.... Maybe I'll try cutting it with a dremmel. Thanks for all the advice!
 
Not a problem, I make custon sized springs

tactical870 said:
Anyone here have experience making springs?
Click to expand...

I have made custom sized springs in my machine shop for other CGNers. If you have not found anything off-the-self, send me a drawing with dimensions and grade of material required and I can run you off whatever you need.

Regards
Robert
 
It's a pain, but it's easier to find a pre-existing spring of similar shape and trim to spec, being careful not to draw any temper.
 
Lawn mowers, clocks and garage doors all may yeild good spring steel. As does VW microbus transaxels and Ski-doo olympic front ski springs. Trunk rod from old car trunks is an excellent material for both springs, firing pins and Elan/olympic ski runners.
 
Send me picture soon as you can if you require it sooner than later, I may have one.
Lay a ruler beside it on different top and side views. .bradburn@yahoo.ca
 
we use banding in the shop for flat springs in a button style contact. put a slight bend in it and works great . the price is right too . get your self a better set of snips or tighten up the ones you have.
 
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