How difficult was it to make the mainspring? I have the same instructions and another set for an earlier pistol and have been wondering how difficult it would be to try.
The springs intimidated me as well, but that's probably a good reason to choose the wheel lock.
Steel selection - almost anything that you can heat treat in a home shop will be superior to what every they used 500 years ago.
In those days metallurgy was akin to witchcraft, and the only alloying elements were native to the ore or picked up from the flux and fuel in the furnace. So the metals we have today are much stronger and better able to handle the stresses of the application than what our forefathers had. If we copy their stuff with modern materials, the chances of success are high.
Making the man spring and spring for the dog/cock
I went to the scrap bin and looked for something about the correct thickness that was used in an application that would have required it to be heat treated in the original application, and came up with an old law mower blade.
I selected it because: It was the right thickness. it had to be tough for the original application, so it probably had enough carbon to heat treat. The blade was also a relatively low cost commodity grade component, so no one was going to use an exotic alloy for the application (IE it probably would heat treat without issue in a home shop).
After selection I cut a test square, heated until it lost its magnetism, and quenched it to verify it would harden and not crack.
Simple file test to verify it got harder and hammer strike in a vise to shatter the metal. I want to see a brittle fracture surface with a fine gray texture.
Cutting - roughed out the oversized blank with an angle grinder and cut off wheel.
Then I tossed it in a brush fire and left it their overnight to soften it.
Filled it to width.
Used the cutting torch to heat it and rough in the form with round nosed plyers.
With the form roughed in I located the jog for the toggle link to rid in and forged that with a simple home made mild steel die - Just a round notch made with a drill bit. I heated the spring and drove it into the notch with a round bar on top to create the C shape. (sure it will ware fast, but I don't plan on using it much)
The loop on the cock spring was started with round nose plyers and tapped into shape around a steel rod on the anvil.
With the form finalized, I cut the notches and drilled the holes and verified it fit.
Then smoothed all surfaces with files and paper. Made sure all the scratches were along the length of the spring, not crossing it.
Finally I did a simple heat treat by suspending it from wire and heating it slowly with a torch until it was no longer magnetic, then quenched in oil as that was sufficient to get the metal hard.
Ran it across a wire wheel to remove the scale and brighten it slightly, then I cooked it in a toaster oven at about 400 F for 1/2 hour.
The hotter you go on the temper, the tougher the part is, but it also takes a set more easily. Lower tempers are harder and less ductile, but will bend farther before snapping. I wanted it soft enough to yield without snapping if I over stressed it. Easier to reharden and temper at a lower temp the to start again from scratch.
Finally check the fit, test the operation, and polish
It is hard to do - compared to what.
Getting the form is not too bad if you have hammered iron for 30 years.
If your not a confident, make a simple hardwood from to hammer the part around from some scrap or an old pallet.
Sure it will smoke and burn, but it will be more than good enough for one part.
