The special Yoke Endshake screw

[blackpowder]

Hello everyone,

I have a model 15-3 from 1972 that has a bit of endshake in the yoke. As far as I can tell, the problem is a worn or improperly fitted yoke screw in the sideplate. Swapping the #2 screw with the # 3 screw, which are the same, didn't help much. I heard there is a special repair screw with a slightly different head that takes up the slack in the yoke button and, more often than not, fixes the problem. Does anyone know where I can get such a screw. S&W says they don't have one.

 

[handejector]

Never heard of it.
First thing I would do is try a new sideplate screw and see if it took up the slack or actually needed fitting. Both of your screws may have been used for the yoke on a gun that old, so both may be worn or fitted at some point in time.

 

[Hondo44]

I have never heard of a special repair screw either.

What you heard about might be the 1988 new style yoke retention screw which is larger diameter, has a spring loaded plunger with a pointy tip, and doesn't require fitting. However, it's not usable in older guns w/o some slight machining. The new groove on the end of the yoke shaft is a V shaped groove; different than the pre 1988 square cut groove.

Remove the yoke and check the groove for a warn area in the rear side of the groove where the tip of the screw rides. You'll likely find a worn area. You can peen that slightly or if severe, build it up a bit by tig welding and refit to the screw. A replacement screw with no wear on it, or a combination of the two, peening and new screw will eliminate the end play in almost all cases.

 

[jbtrucker]

New screws can be found ebay sorry forgot the vendors name

 

[Hondo44]

Screw suppliers:

GUN GARAGE on Ebay (for screws)
http://stores.ebay.com/Gun-Garage

"Aonepawninc" http://stores.ebay.com/aonepawninc
has a bunch of old S&W parts for sale.

Gun Parts Corp: Successor to Numrich Arms; many gun parts.
226 Williams Lane, West Hurley, NY 12491
Phone: 845-679-2417
e-Mail: [email protected]
Web Site: Gun Parts & Firearm Accessories | Numrich Gun Parts

 

[shocker]

gunblue490 in his S&W revolver youtube videos discusses endshake screws. Also says the yoke screw slot can become so worn that peening the slot is necessary for a repair.

 

[Retired W4]

Brownell's or Numrich had shims for end shake, which I've used successfully in the past. It has been so long ago that I really don't remember much about them. I could be talking apples to oranges. Can't remember.

 

[blackpowder]

Screw suppliers:

GUN GARAGE on Ebay (for screws)
http://stores.ebay.com/Gun-Garage

"Aonepawninc" http://stores.ebay.com/aonepawninc
has a bunch of old S&W parts for sale.

Gun Parts Corp: Successor to Numrich Arms; many gun parts.
226 Williams Lane, West Hurley, NY 12491
Phone: 845-679-2417
e-Mail: [email protected]
Web Site: Gun Parts & Firearm Accessories | Numrich Gun Parts

Just ordered a new screw from Gun Garage. Will try that first and see what happens before I start on any of the more complicated repairs.....
thanks to all for the good advice...

 

[Muley Gil]

The Gun Garage link doesn't work anymore.

 

[Jeff in Cincinnati]

Yoke endshake screw

For revolvers made prior to having the current spring loaded yoke bearing setup, there was indeed a yoke endshake screw available to S&W Armorers that could be used to repair a yoke that was loose. This was a sideplate screw that had a tip of larger diameter than standard. The side of the tip of this screw bears on the yoke button and can take up some looseness. However, fitting up a yoke by adjusting the yoke button (not the screw) is a job that requires some training. In fact, I would say it is second only to adjusting the ratchets in terms of difficulty and potential to create more problems than it solves. Often, using the oversize screw tightens the yoke too much, requiring that the yoke button be filed to fit properly again —- and this adjustment by filing is where it is very easy to go too far and ruin the yoke entirely. There is also a way to correct a loose yoke by peening the yoke button at just the right spot, which again requires training. A loose yoke should by evaluated with the cylinder closed, the only position in which yoke endshake creates issues. This is all to the best of my recollection from S&W Armorers School in the early 80’s. The new retention system, which is like what Colt has used for a long time, changed the need to fit the yoke button so carefully and is a big improvement in my estimation.

 

[bgrafsr]

For revolvers made prior to having the current spring loaded yoke bearing setup, there was indeed a yoke endshake screw available to S&W Armorers that could be used to repair a yoke that was loose. This was a sideplate screw that had a tip of larger diameter than standard. The side of the tip of this screw bears on the yoke button and can take up some looseness. However, fitting up a yoke by adjusting the yoke button (not the screw) is a job that requires some training. In fact, I would say it is second only to adjusting the ratchets in terms of difficulty and potential to create more problems than it solves. Often, using the oversize screw tightens the yoke too much, requiring that the yoke button be filed to fit properly again —- and this adjustment by filing is where it is very easy to go too far and ruin the yoke entirely. There is also a way to correct a loose yoke by peening the yoke button at just the right spot, which again requires training. A loose yoke should by evaluated with the cylinder closed, the only position in which yoke endshake creates issues. This is all to the best of my recollection from S&W Armorers School in the early 80’s. The new retention system, which is like what Colt has used for a long time, changed the need to fit the yoke button so carefully and is a big improvement in my estimation.

Yes, there was a side plate screw that had a larger diameter at the tip to correct yoke end shake. When I finished Armorer's School I order a lot of parts from S&W so I could repair our Model 66's. One of the items ordered were the larger yoke screws.

 

[blackpowder]

The Gun Garage link doesn't work anymore.

you can find them on ebay

 

[blackpowder]

A loose yoke should by evaluated with the cylinder closed, the only position in which yoke endshake creates issues.

I didn't know this. how much movement is acceptable? with the cylinder open, I can grab the arm of the yoke and move it noticeably back and forth a bit. With the cylinder closed, however, the movement is much less. In fact, I cannot even see or feel it, I only hear a light clicking when I push on the front of the yoke, where it is flush with the frame, with my thumb.

 

[Jeff in Cincinnati]

Endshake

Endshake, particularly cylinder endshake, can worsen over time if uncorrected and cause misfires in an extreme situation. Endshake worsens over time as parts that are not tight can get battered back and forth when the revolver is fired increasing the amount of endshake over time. This is more likely to happen when a revolver is fired with a lot of magnum or other hot loads. this is less likely, or takes much longer to occur, with a revolver like a Combat Masterpiece. Without inspecting the revolver it is not possible for me to assess the situation with certainty, but your description of only slightly detectable movement when the cylinder is closed doesn’t sound like excessive yoke endshake. Ideally, the yoke button is adjusted so that the cylinder closes snugly, with a little resistance being acceptable but then swings more freely as it opens. Since this was all hand fit “back in the day,” some variation from one revolver to the next was allowed during inspections.

 

[armorer951]

Crowned sideplate yoke screw with oversized pilot, AKA: "endshake screw". As with any older piloted screw, it will likely need to be fit to the button of your yoke. (this is not a "drop-in" part)

Part numbers:

blue: 050490701
nickel: 050490704
stainless: 070170200

 

[blackpowder]

some of you will find this interesting. I called S&W in Springfield to see if I can get one of those special endshake repair screws. After speaking with three different people I gave up. if these mystery screws ever existed they seem to be unknown and/or long forgotten on Roosevelt Avenue.....

 

[blackpowder]

Crowned sideplate yoke screw with oversized pilot, AKA: "endshake screw". As with any older piloted screw, it will likely need to be fit to the button of your yoke. (this is not a "drop-in" part)

Part numbers:

blue: 050490701
nickel: 050490704
stainless: 070170200

@armorer951
The yoke screws from Gun Garage arrived and now after the holidays I'm trying to see if it works. Well it does. After replacing my old screw with the new one and bottoming it out (I don't torque it), the endshake in the yoke is eliminated. No more endshake! However, swinging out the cylinder is not as smooth as before and drags just a bit at the start. After the cylinder is about half way out it goes smooth the rest of the way. Will that work itself out through wear? Or can I do something to make it work smoother? Thanks!

 

[Pine_Worker]

The S&W Revolver Shop Manual by Jerry Kuhnhausen describes how this is corrected.

 

[armorer951]

blackpowder......

Sounds like the new one is very close to the correct fit. Perhaps a little oil on the back of the button where the screw pilot is in contact will help loosen things up a bit. Ideally, the correct amount of contact with the screw as the yoke closes is what is required to hold the yoke in place properly, and without any movement fore and aft while the assembly is closed. A little resistance as the assembly closes is actually desired in this case.

Smith and Wesson teaches that the initial fit of the yoke button to the screw pilot is done by removing material from the contact point on the button itself. As and "end user" however, if fitting of the new screw becomes necessary, I would recommend removal of material from the screw pilot itself, not the yoke button. The reason here is the screw is relatively inexpensive, compared to a new yoke if a mistake is made.

Remember though, if a little fitting becomes necessary, that the yoke button bears against the side of the pilot at the end of the screw, not the end of the pilot. So..... modification of the screw to limit it's contact on the button (make the yoke easier to swing out) would entail making the diameter of the piloted end a bit smaller, not by shortening the screw pilot.

Some "break in" would be expected, so I would suggest waiting a bit, and see if usage and lubricant will help make the interface viable without further intervention.

 

[Arquebus357]

You only have play when the cylinder is open. Is the play between the yoke and the frame or is the play of the cylinder and the shaft bushing ? The screw will only address the former. If it's the latter I'm not sure how this can be addressed. Years ago I asked, here, about what I felt to be too much play between the shaft bushing and the cylinder (the latter) on a model 19. Several replied that as long as the cylinder opens and closes easily and the Cylinder Endshake is minimal (cylinder closed) that I should not be concerned with the play with the cylinder open. They made sure that I wasn't talking about the play caused by a worn screw.