Fly/tumbler for Cochran lock

[gibster]

I recently bought at auction a Cochran flintlock lock kit that was dated 1992. It was still in the styrofoam packaging.  I started to assemble the lock today and the fly was wired to the tumbler, so long story short, the fly was rusted to the tumbler. When I tried to work the fly loose, it sheered off the pin in the hole.  I tried drilling it out but no luck. I don't know if it was hardened or not, so I heated the tumbler red hot and allowed it to cool to try to drill it out again. But still no luck. I don't know if the pin is spinning in the hole or not. so I filled the hole with super glue to try to hold the pin in place to drill it out. Still no luck.  I have a fly for a small siler lock but until I get the pin out of the hole, it's not doing me any good.  Any thoughts on what I can do to remove the pin from the hole?  If not, any idea where I can find another tumbler for the lock?
Thanks.

[JPK]

Drill from the other side and drive it out.

[kutter]

As long as the tumbler has already been through the fire, you can solder the pin into place and then drill it out.

Being that you took the tumbler up to red heat to anneal it, it's probably heat scaled now. That'll have to be cleared off to get any solder, either soft or hard solder to take.

Soak the part in a weak soln of muriaric acid (2 tbs per/ pint water) for a while to clean the scale and any rust off.
Then solder the pin in place,,I'd hard solder it.
Flux well and hope the solder flows well enough down and around the pin in it's seat to secure it.
Drill it out.

You could make an entirely different style Fly and bypass the broken off pin.
Use the style Stevens used on their DST hammers .
The fly does not pivot on an integral pin inserted in a blind hole in the bottom of the cut-out for the Fly.
Instead the Fly is made entirely flat but with a ring at it's top that has a hole through the middle. That hole fits the tumbler axle.
The ring portion of the fly fits in a simple circular cutout plunge milled or lathe turned to the proper depth & width around the tumbler axle to accept it. The rest of the cut-out for the Fly is the same.

So the Fly is pivoting/rotating around the tumbler axle instead of the small integal pin attached to the fly itself. The latter set up being commonly used in these locks.

[Bob Roller]

If the fly had a pin that is broken off in a blind hole then maybe a strong magnet might work.
The shaft that holds the cock would stop any cross drilling.
Bob Roller

[Robert Wolfe]

Seems to me the simplest solution is to use the lock on a gun that does not require a fly. No set triggers.

[Scota4570]

My go to solution for rusty parts is Evaporust.  I normally put the part in an ultrasonic cleaner with the Evaporust.  IN about an hour it is free of all rust and the base metal is not affected. Next time maybe. 

[D. Taylor Sapergia]

To anneal that tumbler so you can drill out the stud, build a small hardwood fire and get a nice bed of red embers.  Then heat the tumbler bright red and drop it into the coals.  Let the fire burn out and then fish out the tumbler from the ashes.  Now it'll be dead soft.  Use a new drill bit to drill out the tit.

[gibster]

I appreciate all the tips and advice on what to do with this thing.  Well, right, wrong or indifferent, here's what I ended up doing.  The pin was spinning in the hole when the drill bit came in contact with it but would not come out regardless of what I did. With it spinning, the bit would go no further. I followed the advice of kutter and soaked the tumbler in a solution of water and muriatic acid to remove any scale and/or rust. Then tried to solder the pin so that it wouldn't spin when drilling. But no luck.  I wasn't able to get any of the solder to flow around the pin into the hole. So with really nothing to loose, I used a larger drill bit that would not center on the broken pin but would catch it on the side of the bit and drilled it out. I made a pin that would slip fit onto the hole and silver soldered it into place. Drilled a new hole for the fly and it looks like it will work fine.  Now the only issue is that the tumbler is fairly soft so I don't know how long it will last.  I really can't harden it because the solder will melt, pin will fall out and I'll be back to square one. I honestly don't know if the tumbler was originally hardened or not.  Any thoughts on having a tumbler that isn't hardened?

[rich pierce]

If you brazed your plug in place it could be case hardened as the temperature for brazing (with real brass) is higher than the temperature required for case hardening. This is how lock parts were traditionally repaired.

If the flow temp of your silver solder was under that for brass, this approach will not work.

A soft tumbler will quickly become unsafe to hold in the full cock notch. I’m guessing you plan to use set triggers or a light simple trigger pull. If not, a fly is not necessary.

[Scota4570]

The fly pin is captured by the bridle and plate, why solder or braze it? 

[gibster]

The fly pin is captured by the bridle and plate, why solder or braze it?

Because the hole had to be drilled out quite a bit larger than the original pin hole.

Rich had a great point and since I want the lock to last and be safe, I'm going to undo what I did as far as soldering a pin into place since I can't harden it without loosing the soldered pin. So, I'll thread the hole and put a piece of threaded screw into it, redrill for the fly pin and I should be good to go with hardening and tempering it. Thoughts???

[T*O*F]

Thoughts???

Why not remove the old pin, harden the tumber, and install a new pin that is a press fit into the hole.  It ain't goin' nowhere.

[gibster]

Thoughts???

Why not remove the old pin, harden the tumber, and install a new pin that is a press fit into the hole.  It ain't goin' nowhere.

That's a great idea, and would be easier than threading the hole.  Appreciate that.

[EC121]

A dab of JB Weld will hold it in.

[Scota4570]

The fly pin is captured by the bridle and plate, why solder or braze it?

Because the hole had to be drilled out quite a bit larger than the original pin hole.

Rich had a great point and since I want the lock to last and be safe, I'm going to undo what I did as far as soldering a pin into place since I can't harden it without loosing the soldered pin. So, I'll thread the hole and put a piece of threaded screw into it, redrill for the fly pin and I should be good to go with hardening and tempering it. Thoughts???

Make the hole round and make a two diameter pin?  I still see no reason to solder or braze it....  It is captured by the plate and the bridle?

 A dab of glue would be fine.  I keep loctite shaft sealant around for this kind of thing.   They make an oil proof version.  Of course I am not working on it so it is just a guess.