Yoke endshake repair

[3T'sX3]

I have a nice old 27-2 with about .004 to .005 YOKE endshake. Cylinder endshake and barrel/cylinder gap are O.K. I am not in favor of using yoke washers. I am wondering if the endshake screws sold by Midway and Brownell's are an effective means of correcting the problem. How are these screws made? I would think that they would have to be larger in diameter than standard screws.

Another option, and more risky, would be to peen the end of the yoke shaft. Is it necessary to peen all the way around the circumference of the shaft or only the 90 degree portion that bears against the endshake screw? How much striking force does it take to peen this edge?

 

[S&W revolverman]

Yoke Endshake Repair

The first thing I'd do is try this. Remove the other sideplate screw (the one just below the yoke screw with a round head, not the flat headed one), and try it in the yoke screw hole. Someone may have disasembled this revolver and not put the screws back correctly. The yoke scew is fitted from the factory, the other round headed sideplate screw is not a fitted screw.

Hope this helps
chris

 

[cmj8591]

Try Chris' solution first. It may solve the problem.

The next step is to peen the yoke button. Use a small 4oz hammer and be sure to support the front of the yoke when you strike it. You only need to hammer on the 45 degrees from the 3 o'clock position to the 6 o'clock position on the button. (Looking down on the button hold the yoke so that the cylinder barrel is at the 12 o'clock position.) After hammering you can use a Barrett file to fit the button to the screw. (Hold the yoke so that the button is facing down and take a couple of file strokes on the area opposite where you just hammered on the inside of the button where it bears against the screw.) This is a trial and error fit so go slow and check your work frequently. After you are done recheck your cylinder endshake.

I've never had very good luck with the washer fix and have seen them fail and jam up the yoke several times. The oversized screw is also a fix but most likely you will need to fit the yoke anyways. The peening method works well and is not as difficult as it sounds and if done properly will last a long time.



Good luck

 

[3T'sX3]

Thank You for the replies. Is their a way to support the front of the yoke without scratching the finish while you are peening? This old 27 has a beautiful blue job.

I am not in favor of using yoke washers because they fix the yoke in a position too far forward. Would like to move the yoke rearward where it belongs. Currently the yoke protrudes out beyond the frame. Looks bad.

 

[Bert Man]

Thank You for the replies. Is their a way to support the front of the yoke without scratching the finish while you are peening? This old 27 has a beautiful blue job.

I am not in favor of using yoke washers because they fix the yoke in a position too far forward. Would like to move the yoke rearward where it belongs. Currently the yoke protrudes out beyond the frame. Looks bad.

New to the forum, but not new to S&W. May be able to help you. cmj 8591 is right about how to fit endshake yoke screw with a Barrett file. If you don't have to stretch the yoke barrel to far the original screw might work without re-filing. Only need to lengthen it enough to just eliminate endshake. Best way to support yoke barrel is to insert a yoke alignment tool through it then lightly peen forward on the front edge of the yoke barrel. Tap a little, check fit. Repeat until no more endshake. You mentioned that the yoke stands away from the frame somewhat which indicates yoke probably out of alignment. You do need a yoke alignment tool to correct that. Yoke alignment tool is a specialty armorer tool. Sorry, but I don't know any other way to do that. Maybe someone can offer an alternate way. Hope this helps a little.

 

[dfariswheel]

The "usual" peening method is to lay the yoke on a round lead or Babbitt bar to support it and to prevent scratching or denting of the yoke, while you peen the yoke "button".

 

[cmj8591]

The Babbitt and the hard wood wedge are the most important tools in the revolver armorer's kit!

Usually the bar is about 1 inch in diameter. Lay it on the bench and support the yoke so that as you are peening the button the opposite end of the yoke is resting on the bar. I used to have all of the diagrams and I wish I could put my hand on them now so that I could post it for you. Let me suggest this: if you are working on revolvers and doing these types of repairs invest in Kunhausen's "The S&W Revolver". It is available from Brownell's and is worth every cent.

 

[Bert Man]

yoke endshake repair

The Babbitt and the hard wood wedge are the most important tools in the revolver armorer's kit!

Usually the bar is about 1 inch in diameter. Lay it on the bench and support the yoke so that as you are peening the button the opposite end of the yoke is resting on the bar. I used to have all of the diagrams and I wish I could put my hand on them now so that I could post it for you. Let me suggest this: if you are working on revolvers and doing these types of repairs invest in Kunhausen's "The S&W Revolver". It is available from Brownell's and is worth every cent.

cmj8591 thanks for jumping back in and setting the OP back on the right track. Been a long time since S&W Armorer School (1979). Old brain cells got me on the procedure for endshake cylinder instead of endshake yoke. I agree about the babbit and wood wedge; couldn't do without them. I always check my work with the yoke alignment tool to make sure alignment is close as possible. Can get fairly close without it though. I never will forget the first time an officer came to my office a Mod. 66 with cylinder bind. When I struck the cylinder face a couple of times with the babbit bar the guy had a surprised look on his face, I freed up the cylinder, showed him it then rotated freely, a returned the weapon to him. He replied,"well I'll be d---ed." After that I always felt it best that to operate in private when any judicious babbit work was needed.

 

[3T'sX3]

Thanks for the advice everyone. Now to find some lead or babbit bar.

One more question. I have looked at the button very closly under magnification. It looks as if their is a slight cam or inclined plane on the inside of the button in the notch where the screw rides. Can't tell for sure if it was machined that way or if it is just a wear pattern. Do I need to try to preserve that cam when I'm filing and fitting the button to the screw?

 

[Bert Man]

Thanks for the advice everyone. Now to find some lead or babbit bar.

One more question. I have looked at the button very closly under magnification. It looks as if their is a slight cam or inclined plane on the inside of the button in the notch where the screw rides. Can't tell for sure if it was machined that way or if it is just a wear pattern. Do I need to try to preserve that cam when I'm filing and fitting the button to the screw?

May possibly find babbit bars from Brownell's. Yes, that cut you see was made at the factory when the fitter installed the yoke. Try to maintain that contour if you have to file the yoke button. If you have done any filing already insert the yoke back in the frame, install the yoke screw, and try to rotate the yoke in the frame. If you feel any tightness the yoke button must be filed. Remove it from the frame again. Please be aware that there is specific way to make the strokes with the barrett file. Don't think I can describe it properly in writing. If you make uneven file strokes the yoke will have tight places and loose places at different points of roation when installed. If you file a little too much or in the wrong way you screw up the button and the yoke is a factory-fit-only part. As was previously posted, I strongly suggest you obtain the Kunhausen S&W Revolver Book before trying to complete this repair or send it to S&W Service Center for the repair. A fine S&W revolver is a piece of genuine American art and is worth doing it right. If you do proceed to attempt the repair please go slowly, very light file strokes and frequently re-install the yoke in the frame and check you progress. Repeat this until the yoke turns freely (not loosely) and uniformly with yoke screw installed. If at any point you are not absolutely sure what to do, stop and obtained skilled assistance. Good luck!

 

[dfariswheel]

Thanks for the advice everyone. Now to find some lead or babbit bar.

One more question. I have looked at the button very closly under magnification. It looks as if their is a slight cam or inclined plane on the inside of the button in the notch where the screw rides. Can't tell for sure if it was machined that way or if it is just a wear pattern. Do I need to try to preserve that cam when I'm filing and fitting the button to the screw?

The "cam" is a sign of someone mis-installing the cylinder retention screw, or installing the WRONG screw.
When they opened or closed the cylinder the improper screw gouged that cam or ramp on the yoke.
Do not preserve it.
If possible, use a fine file to clean it up as well as possable.

 

[Alpha426]

Be careful not to deform the yoke button when using the ball peen hammer. There's a tool that can prevent that by applying pressure only to the area needed. See the attached photo.

The lead babbit is in the background.

 

[3T'sX3]

Be careful not to deform the yoke button when using the ball peen hammer. There's a tool that can prevent that by applying pressure only to the area needed. See the attached photo.

The lead babbit is in the background.

Wow! Very Clever idea. I assume this is a shop fabricated tool. Have never seen one of these in any catalog. I'm still looking for some lead round stock. I think my local gun shop has lead bars for bullet casting that may work.

 

[Alpha426]

I believe these tools were made by a tool supplier located near S&W's Springfield facility who specialize in S&W firearms. I don't remember the name.

 

[ken158]

Bert - I saw you mention you were at the armorer's school in 1979 - I was there in 1979 also. Do you remember which school you attended? I was there in June. Been a long time but I have guarded my book and tools and certainly remember making a bunch of model 64's during those two weeks.

 

[Bert Man]

S&W Armorer School 1979

Bert - I saw you mention you were at the armorer's school in 1979 - I was there in 1979 also. Do you remember which school you attended? I was there in June. Been a long time but I have guarded my book and tools and certainly remember making a bunch of model 64's during those two weeks.

Ken158 your the second armorer school graduate to contact me within a week. Didn't know this many of us old guys were still around. I was there the first 2 weeks in Aug. '79.
Never can forget because one morning in early Aug. temp was mid 30with a bit of light frozen precip and being from S. MS that was a bit unexpected that time of year. Yes, we also built a bunch of Model 64's. They must have had a big contract going on that model. I also still have my manuals and tools. In 1991 I left my original dept. to go to another. Had quite an inventory of S&W parts and since they had no other prospective armorer the property officer let me keep them. Didn't have to buy many parts for years. Haven't worked on many S&W recently as in 1993 we went to the Glock 21. Retired Sep. '08. Still have a 66-1 4-inch and 36-1 2-inch though and always will. Great to hear from you. Sure brings back memories.

 

[3T'sX3]

Endshake repair completed successfully. Thanks to everyone for the advice. It took a lot more striking force to peen the button than I anticipated. Fortunately, I resisted the urge to get a bigger hammer. Time will tell if the repair is durable. It concerns me a bit that the compressive load of the springs is now concentrated on the tip of the yoke screw. That load should rightfully be assigned to the yoke to frame flange. We shall see how it holds up.

 

[tomcatt51]

It concerns me a bit that the compressive load of the springs is now concentrated on the tip of the yoke screw. That load should rightfully be assigned to the yoke to frame flange. We shall see how it holds up.

It should concern you. The yoke should fit tight against the frame. The shims make up for a yoke that wasn't fitted correctly or loosened during use. The sideplate/yoke screw is there so the yoke/cylinder doesn't fall out when you open the cylinder and to hold it in place so it will close properly. Fire many rounds and you'll be right back where you started. The screw will wear into the yoke until the yoke sits against the frame like it's meant to.