A puzzle, concerning a revolver cylinder

[contender]

I recently received a NM Ruger 45 acp cylinder.
Apparently, in it's past, someone wanted to modify it to fit something other than a Ruger. The cylinder boss end, where the base pin enters, has been tapped with threads, about 1/2 the way down the center base pin hole. I have asked my gunsmith, and we both are puzzled as to what gun this MIGHT be used in,, with this modification.
I'm open to any & all wild guesses & speculation. See the picture below, and start guessing!

 

[planetcat]

Pencil holder? Maybe an old rifle that used cylinders (not sure what they were called).

 

[PotatoJudge]

Shift knob on an old hot rod I hope!

I wonder if that could be bored out and a Colt style bushing installed.

 

[nvbirdman]

Maybe wanted to sleeve it to adjust the BC gap?

 

[roylt]

Who says it was used on a gun project.

Some sort of gun art maybe.

I do like potatoes idea about a shift knob!!

 

[mike7mm08]

Don't see how it could functioned in any gun. How could it revolve if it was screwed onto something

 

[tsubaki]

A possible shorty barrel situation and this would allow a threaded pin to be retained.
If so, it seems like a solution to a nonexistent problem.

 

[clintsfolly]

It's a diemaker thing! They never saw a hole that they didn't want to tap!

 

[contender]

We discussed the bushing thing. But,,,, the dimensions are all wrong. It's a lot of fun trying to figure out this. The sad part is how a good part, that's desirable, was ruined.

We have discussed the possibility of welding a ring of metal around the hole, filling it in part of the way. Then, re-drilling it for the base pin, and facing off the boss to fit. We think this might work, as only about 1/2 of it has been tapped.

 

[rugerguy]

sorry, was NOT to be used in any form of gun we can even imagine, depending on the threads as to either the "pencil holder" (we done that MANY time over the years) or the gear shift knob and that thread is too small for most of the shifters we've mounted 'pool' balls, monkey skulls, etc... 8) :roll: :wink:

( and YES as noted above, ANY "retired" machinist, tool makers' dream,, "thread 'em ALL...." :mrgreen:

 

[Jimbo357mag]

Look at those scratches on the cylinder face. What the heck? Maybe for a lamp?

 

[Mus408]

It's a diemaker thing! They never saw a hole that they didn't want to tap!

Hey be careful there!

Any extra holes I made were tapped and filled with a plug then stamped "Oil Here" :mrgreen:

 

[Mus408]

You mean you guys couldn't figure that out??? Oil retention grooves! :mrgreen:

 

[DGW1949]

We discussed the bushing thing. But,,,, the dimensions are all wrong. It's a lot of fun trying to figure out this. The sad part is how a good part, that's desirable, was ruined.

We have discussed the possibility of welding a ring of metal around the hole, filling it in part of the way. Then, re-drilling it for the base pin, and facing off the boss to fit. We think this might work, as only about 1/2 of it has been tapped.

In all due respect, I'm not so sure that your cylinder has been "ruined".
If I'm guessing right, all someone did was tap some 5/16" threads into the existing (1/4") pin-hole, which indicates that a 3/8" hole could be bored in order to remove the offending threads, after which an appropriate bushing can be fashioned and pressed into place.
That same sort of a thing has often been done in order to "fit" a cylinder with a short gas ring to a gun which needed a longer gas ring. I've done several of those myself, as-has others...and as far as that goes, I've seen one which had had it's whole length re-bored so a full length, Colt SAA-style bushing could be used.

Any machinist worth his salt could fix that right up for you, easy-peazy...just make sure he uses an appropriate material for the bushing, something like 4140...NOT cold-roll.
Better that than taking the chance of welding having a negative effect on the factory heat treat, eh?

Hope this helps.

DGW

 

[s4s4u]

I second the shifter knob notion ;-)

 

[Chuck 100 yd]

I have seen grooves similar to those cut into black powder revolvers. They
Are ment to defeat black powder fouling from tying up the cylinder, a place for lube.

 

[contender]

I'm going to see about what the thread pitch is.
And DGW1949,,, I like the way you think. We may try that instead. I too wondered about the heat of welding.

Maybe it was an idea for a shifter knob,,, but most shifters I ever saw had a larger threaded shaft.

 

[Quattroclick]

I have a different possible interpretation. Does the pin fit the hole properly? If so, the threads may be knurling. This process is used to reduce the diameter of the hole, and as someone pointed out above, leaves a groove for lubricant. Likely this would have been done to correct a loose pin fit. If the pin fits properly, I would use it. If not, I would bore out a section and press in a bushing.

 

[Dave P.]

Those are not any standard thread form. I'm with others that somebody tapped it
then reamed or honed it, maybe in attempt to hit a particular id.
No big deal to bore and sleeve it.
Dave
Edit.....I'd establish the centerline by indicating the charge holes, slight
time eater to set up but worth it.
Definitely be looking at total length and BC gap before investing any time in it.
If you were lucky it would be a bit long and you could also "square" it up to
fit the gun.

 

[contender]

No, these are not lube grooves. Definitely screw threads. The hole for the threads is larger than the base pin. Not by a large amount,,, but enough. Considering the bushing route.