Crane screw?

[ISCS Yoda]

I NEVER pretend that I know what all the internals are for on guns - I am extremely unhandy so I shoot them and clean them but never fix them. I know a great deal about guns but I keep out of the mechanics because I'm dangerous there.

That said, I recently wrote about a friend's M629 (late 80s Lew Horton 3") that went to the gunsmith and when it got home the cylinder fell off. We couldn't determine what was wrong and it went back to the gunsmith.

He told us he didn't notice that the crane screw had sheared off and that's why the cylinder fell off. He replaced the screw, all is well. His assistant pointed to the screw on the far front of the sideplate as the offending screw.

Question: Is that forward screw the crane screw?

Question: Can you explain to me, please, what it is that that screw actually does - because I thought it held the sideplate on with the other two screws, that's all.

Thanks.

***GRJ***

 

[ISCS Yoda]

This was the first thread:

http://smith-wessonforum.com/s-w-revolvers-1980-present/390636-3-m-629-weird-issue.html

 

[Muss Muggins]

That screw performs two functions. If you look at the crane, you'll see there's a channel all the way around the rod at the end. The crane screw goes through the side plate and anchors the crane/yoke to the frame.

 

[Pizza Bob]

While I apologize for this being a Taurus revolver, it was the best image I could find (even has the callouts already included) to illustrate what the OP asks...

#2 is the hole for the crane screw, which also serves to secure the front of the side plate. The end screw protrudes into the groove cut into the front of the crane shaft (#6) thus preventing it from coming (forward) out of the frame.

S&W has used two designs - one a solid screw of a precise length and, two, a screw with a spring loaded end that serves as a plunger and actually contacts the shaft. If that screw gets sheared and the gun gets tipped down with the cylinder open, the yoke assembly will fall out of the frame.

HTH.

Adios,

Pizza Bob

 

[kaaskop49]

attn ISCS Yoda/ Pizza Bob

Dont'cha just love the handle Pizza Bob? Wish I could find decent pizza out here in Vegas...

Anyhow, that S&W 3-piece crane screw is captive (I believe that is the term), the parts remain together as a unit. FWIW, on a Colt, that same screw is also 3-piece, but is NOT captive. Interesting few moments one day, trying to find 2 of those pieces from a Colt OP! Finally did.

Hey Yoda, remember me, the J-frame magnum shooter? Best wishes and good shooting.

Kaaskop49
Shield #5103

 

[ISCS Yoda]

Thanks, y'all, I appreciate it.

Kaaskop49, I remember......you're still doing it?

I wi$h I could be your orthopaedi$t!

***GRJ***

 

[Pizza Bob]

Wish I could find decent pizza out here in Vegas...

Good pizza, as well as a variety of types is one of the few good things about NJ.

 

[murphydog]

In Smith-ese, that would be the "yoke retention screw" . Good illustration above.

 

[ISCS Yoda]

Good pizza, as well as a variety of types is one of the few good things about NJ.

If I didn't have family in NJ I'd say the pizza was the ONLY good thing!

***GRJ***

 

[BruceM]

In Smith-ese, that would be the "yoke retention screw"

Yep, that's because Smith & Wesson revolvers have yokes and not "cranes". It is a different screw than the other side plate screws and must be reinstalled in it's original location.

Bruce

 

[ISCS Yoda]

Somewhere on this Forum, not too long ago, there was a discussion about yokes and cranes and the fact that they were the same thing depending upon manufacturers' nomenclature. So, okay, I knew that, but my gunsmith used the term "crane". Had he said "yoke" I would have said it, too.

***GRJ***

 

[gubowner]

had the same thing happen to me with 1980 vintage Tarus 66, all the side plate screws had the exstension for the crane retension grove. All I had to do was swap one for the worn out one. Kept on shooting (pew pew pew pew pew pew!)

 

[bgrafsr]

had the same thing happen to me with 1980 vintage Tarus 66, all the side plate screws had the exstension for the crane retension grove. All I had to do was swap one for the worn out one. Kept on shooting (pew pew pew pew pew pew!)

Both long side plate screws have the "extension" or nub on them, but the "yoke" screw has a larger diameter extension (nub) than the other one does. That's why the screws should be placed back into the side plate screw holes from which they were removed. If not, you can end up with "yoke end shake".