I have a K-38 with a bit of cylinder end shake. I know if I shim it say by one .002 bearing it will set the cylinder back and open the barrel cylinder gap by the same amount. But if there is any yoke end play, by putting a bearing on the yoke stud, would that have any effect on barrel cylinder gap? I have not checked the yoke yet, so that may not be a problem, but I am curious about any chance of further increase in barrel cylinder gap if indeed the yoke is also a problem. Thanks for any light someone can shine on this.
Fix the yoke shake first. Here is how.....
Throw the yoke bearings away!
There is a way to peen the yoke button to tighten it up. It's easy to do too.
But first, try swapping the bottom 2 screws, you might get lucky and then your fixed up, if not look up in that FAQ for the peening method.
500 Magnum, thanks for the advice. I swapped the screws with no luck. When I get a chance I will do as you suggest on the yoke button. I also have a Heavy Duty with the same problems. Again I swapped the screws with no effect. But when I put the screws back in original position and tightened the yoke screw, the yoke became solid as a rock, but the cylinder was a bit hard to open. I loosened it some until the cylinder opened with just a bit of drag and the yoke was still rock solid. I'm not sure if that is right, as under fire, the screw may loosen again. Of course it would be an easy fix back to where it should be. Is that correct?
I'm not sure if that is right, as under fire, the screw may loosen again. Of course it would be an easy fix back to where it should be. Is that correct?
Check yoke endplay with the yoke screw removed and the yoke closed. If there is yoke endplay, shim it. Power's has both yoke shims and cylinder shims. You'll see there's a thrust surface on the yoke that limits the yoke's forward movement when closed that SHOULD be in contact with the frame with the yoke closed. Use the yoke screw and button to minimize endplay with the yoke OPEN so the cylinder will close.
You can use the yoke screw and button to set the yoke closed endplay but there's so little bearing surface the screw will just dent the yoke button until the yoke and frame are again in contact and your yoke closed endplay is right back, along with an equal increase in cylinder enshake.
When you tighten the yoke screw and if the yoke swings tightly, the screw it tool long and has to be fit. Use a file and file the end of the screw a few strokes at a time and check the fit. Ideally you want the screw snugged up yet there is a little drag on the yoke as it swings out.
When you peen the yoke butten, look at where the rub marks are on the button. Only where you see the rubbing is where you deform it slightly. Once the button is dinged try that screw again. You will see the yoke gets sucked up to the frame and if you over do the trick you will need to file out the ding until it works like it should.
That's how the shop will fix it. S&W won't use shims.
That's how the shop will fix it. S&W won't use shims.
Correct. Peening the button is the "traditional" method. If the yoke (closed) endshake is "out of spec" S&W will replace the "factory installed only" yoke. For the rest of us, well some anyway, to get the same (or better toleranced) results we use Powers yoke shims. The factory has (or had) lots of yokes to choose from to select fit them, the rest of us don't. A well fit new gun will have near zero yoke closed endplay with the yoke screw removed.
There is a simple problem with the peened button method. the closed yoke endplay quickly returns when the gun is fired. The yoke screw will dent the button until the yoke /frame thrust surfaces contact and will then stop. The yoke open endplay is usually still fine.
I realize the peened button is the traditional method (and can be necessary to adjust yoke open endplay) but shimming the yoke (to set yoke closed endplay) is the durable repair.
Six words of wisdom
The S&W revolver: A shop manual
Jerry Kuhnhausen is brilliant.
This book changed my world... A no frills approach to everything from taking a side plate off to bluing.
Amazing, I was able to put bearings in a hammer, change a hand spring, smoothed out the DA on an old 625 and all without shooting the rebound spring across the room. His pages on end shake are fantastic.
With that book and the kind & generous knowledge disseminated by the wonderful members of this forum, there is no revolver problem you can't fix.
Good luck
If you look at what causes endshake yoke you will see why shims may not work. (This relates mostly to older versions that do not have the spring loaded yoke screw.) The end of the yoke screw is very small in diameter, and, it is round. The area of the yoke button that it contacts is flat. Recoil causes the screw to peen a dimple into the yoke button which causes endshake yoke. If you shim the yoke to remove endshake it will push the dimple into contact with the screw. If the dimple is shallow this will cause a minor dragging when opening the cylinder. If the dimple is deep it may lock up the yoke, not allowing the cylinder to open. The area where the dimple is must be filed flat, removing the dimple. The button is then peened to move metal into contact with the screw. There was an earlier posting on the Forum that had to do with the side of the yoke screw being filed flat. I believe this was an attempt to reduce the occurance of endshake yoke by having a flat portion on the screw contacting the flat portion of the yoke button.
Just my $0.02.
KAC