Cylinder Timing a Revolver

teehouse

I have two revolvers, same model & manufacturer. One came with 2 cylinders 22mag & 22lr, the other with magnum only. I am told the cylinders may not interchange because of cylinder timing. I am very technical and mechanical oriented and feel confident I can acomplish this if armed with a little knowledge.
1) What is the procedure for checking timing?
2) Can I make a tool for timing? A turned down bullet on a long
screw handle or perhaps a drill bit or must this be purchased.
3) How is the adjustment made? I assum with the latch at the
bottom of the frame?
4) I haven't found any Gunsmithing FYI or How To websites.
Does one exist?
Thanks in advance for any response and I hope this simulates some gray matter amongst this outstanding community.
TeeHouse

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rhmc24

Two checks to do. Get enough light into the cylinder and look down the barrel (UNLOADED) to see that the cylinder bore aligns with the barrel. Check all cylinder bores. If when you slowly raise the hammer to full cock, the cylinder turns to where the bolt drops in place to lock it for firing it is timed properly, provided it passes the above eyeball test. The 'bolt' is the little part that comes up from the bottom of the frame and drops into a slot on the side of the cylinder. If you install a cylinder that is new to that gun, and if it does not time up properly, BE AWARE that if you modify the hand to time that cylinder, it will affect the timing of the original cylinder. Assuming that the hand and bolt are doing their job, there are mechanical defects that can cause timing faults. One is damage or a machining error of the star (ratchet) that the hand pushes against. Another is incorrect machining of a bolt slot (or slots) on the cylinder. Another I experienced was one cylinder bore not spaced correctly. These are rarely found on pieces from 'name brand' manufacturers. Problems with cylinder manufacture are fixed by replacing the cylinder or by returning the gun to the maker. Trigger and hammer faults can give the illusion of timing problems but that is really another subject. Hope this helps, Robert

teehouse

Hey, got it. Thanks for the explanations. The key info for me was the bolt falling in the cylinder slots while the cylinder is aligned with the barrel bore. Getting light and an eye into a 22 barrel sounds like borescope time to me. I don't have a $200+ dollar scope. That is why I suggested using an alignment rod, like the shaft end of a drill bit a few .001" smaller than the bore. If it strikes the cylinder at the bore/cylinder interface with the bolt in latched up, the cylinder is not TDC.
I had not thought of the cylinder hand making a short/long stroke. It does seem unusual that modern CNC manufactured parts would be incompatability. Different runs on different machines could be a source for error but again most manufacturerers now days have tremendous automated inspection tools capability.
Anyway, thanks for the insight. That was the little bit of thought I needed. I think I will swap cylinders and inspect the alignment/lockup myself. If it does to pass inspection I'll mail it back to its mother.
Thanks again for the response,
TeeHouse

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I hereby re-affirm my support to all individual citizens for their rights granted by the U.S. "Bill of Rights".


Edited by - teehouse on 07/14/2002 00:30:31