(Please move if miscatagorized) fitting cock to tumbler (repair)

[Greywuuf]

Not really a gun building topic... it is a repair question. Working on turning an late percusion target gun back into a regular shooter and my hammer is very loose on the tumbler...I figure I can either build up the tumbler shaft or the hammer hole... either with brazing or more invasive with tig welding.... I can try to place shims in the hole or I can buy a new hammer ( looks very similar to several pieces offered by TOW.   Shims might be tough as the gap is pretty small and they would be very thin.

Thoughts or suggestions

[rich pierce]

Getting some braze in the square hole will usually work for a couple thousand shots.

[whetrock]

Have you had the lock out and looked at it with the mainspring removed? How well do things fit? I asked because if the tumbler may need replacing anyway, then you could solve the problem with the fit to the hammer at the same time.

[Greywuuf]

I have had the lockout but not removed the main spring, i suppose that is excellant advice, it does seem to function well and I don't have a lot of slop on the tumbler but as you said it was under tension.

[Birddog6]

Were it me, I would disassemble the lock to see the true wear. Tension on it can give false indications. Cause you may do a bunch of work & find out you had other issues, then have to do it all over, more parts $, more shipping costs, etc.  I suggest you pin down the true problem First, then proceed.

[bluenoser]

Assuming the tumbler is in decent shape, I tighten things up with shims made from annealed feeler gauges.  In reality, annealing might not be necessary.  I only shim two adjacent flats in the cock.  After selecting a feeler gauge that is just a little over sized, I solder it onto one flat and file for a tight fit on the tumbler shaft.  Soldering a shim onto an adjacent flat would likely cause a problem with the first soldered joint, so a different approach is advisable.  The second shim can be epoxied in place and, again, filed for a tight fit on the tumbler.  Alternately, a shim of appropriate thickness can be selected and loose-fit as the cock is installed.  Feeler gauges are a great resource for that due to the selection of thicknesses.  Trim to width and extra length and test fit to find the correct thickness.  For final installation, butt the shim up against the shelf on the tumbler shaft and press the cock on.  Once on, trim the excess length off the shim and install the screw.  The down side is that a loose shim can be lost if the cock is later removed.
There is a perhaps better approach that had not occurred to me prior to posting this reply.  The second over-sized shim could be soldered to the adjacent flat on the tumbler shaft and filed for a snug fit.  Think I will try that next time.

[Bob Roller]

One repair I did for this was tapered shims driven into the spaces between the hammer and the tumbler shank.When driven tight I carefully filed them to  height that allows the shims to be crushed by the hammer screw.
Bob Roller