main spring stud

[westbj2]

There are a number of ways to fabricate the main spring stud, but I think a tool similar to this one was used by some of the 19th century British spring makers.  The tool quickly cuts an accurate round stud and leaves the base as a .005" rectangular standoff so that the spring does not rub on the lockplate.  If you look closely you can see the similar standoff on the antique spring. Lots of filing left to do!
Jim

[Bob Roller]

That's a miniature hollow mill and I use one after rough filing the mainspring
stud and on the link that captures the main spring. I make mine with a #44 drill
and make the mill from water hardening drill rod.These little mills are easy to make and
I have several in different sizes that I made years ago.

Bob Roller

[45-110]

your milled stud picture looks like you did it after bending the mainspring? i have always profiled the stud when the spring blank is flat so as to be able to secure it in the vise. then the cutter will not hit the other leg the is bent. your effort is commendable, a sloppy fitting square pin in the oversize lock plate hole is one of my pet peeves on production locks.
best
kw

[westbj2]

45......
This application is a back action lock and has an internal integral hook for a screw head on the rear of the plate.  Hook body is only about 3/8" behind the stud hole inside the plate.  Started with the bend and placed the stud later to assure proper fit in a crowded space.
Jim

[Bob Roller]

your milled stud picture looks like you did it after bending the mainspring? i have always profiled the stud when the spring blank is flat so as to be able to secure it in the vise. then the cutter will not hit the other leg the is bent. your effort is commendable, a sloppy fitting square pin in the oversize lock plate hole is one of my pet peeves on production locks.
best
kw

I always finish the round stud after bending the mainspring and rough cut it
with a square medium cut file with one flat ground smooth and then finish with the
hollow mill. Never any trouble with the mill hitting the lower limb.

Bob Roller