Endshake vs runout (?)

[85Ybody]

I just picked up a 64-5 so I could inexpensively start learning the S&W.

First off, I do have a slightly bent extractor rod. I've looked here how to straighten it, but since the knurls are slightly blemished, I think I will just go with a new rod. If I am looking at the right part, they are only about $8.

Now that I've torn it down (and am currently limited to books on hand at the time which are from my library and using the internet), I can't find anything in the books on what I would consider runout on my yoke barrel when the cylinder is installed on it. Maybe this will describe the problem better, and since I do not believe it is endshake, someone might be able to point me to a gunsmithing term so I can do a more refined search.

When the cylinder is locked, endshake (if any) is less than my 0.0015" feeler. However, I can rotate the cylinder slightly when it should be locked. I am unsure the correct way people report this movement (which would probably be in degrees). I am not sure what the allowable limit is, but it is not "rock solid". So in looking at this, I swung the crane down and checked how tight the cylinder was on the yoke barrel. With the extractor rod pointing left and running left to right, I can slightly rotate the cylinder in a clockwise and CCW direction. This is why I was considering it to be runout.

If I look at a factory fix of correcting endshake, which is stretching the yoke barrel, I would think this would in turn make the OD of the yoke barrel smaller and lead to more of what I have. I am making loaded assumptions here, but in my mind, that would do the same thing that I am experiencing now.

Maybe I just need to know the correct dimensions for the OD of the yoke barrel cylinder bearing surfaces (pic in post 8 of the FAQs here http://smith-wessonforum.com/s-w-smithing/94072-faqs.html ) and the ID of the cylinder.

I might be chasing down a problem that doesn't exist.

Thanks!

Matt

 

[tomcatt51]

Sounds like you're chasing a non-existent problem. Endshake sounds good (you need some, usually .001"-.002" on a revo that's going to be shot DA) and with the S&W design there is always some cylinder rotation when the cylinder is "locked" and it's not detrimental.

 

[dfariswheel]

If I'm reading right, with the cylinder closed, you can turn it slightly clockwise and counterclockwise.

If so, not only is this totally normal, its necessary in the S&W for proper operation.
Many people hold the trigger on a S&W back and notice some rotation movement and think the gun needs work.

Fact is, the only gun in which this is a valid test is the old Colt action like the Detective Special, Python, etc.
Only the old Colt action locks the cylinder tightly when the trigger is held back.
In the S&W, Ruger, Dan Wesson and others, the cylinder is specifically designed to be slightly loose when the trigger is held back.
This is to allow the chamber to align itself with the barrel when the bullet passes into the bore.

How loose the cylinder is, whether with the trigger held back or the action at rest, is not something to which S&W assigns a specification.
The only test is whether the revolver is accurate and doesn't spit bullet metal.

In other words, your S&W is operating exactly the way it was designed to do.

 

[85Ybody]

Thanks to both for the description of correct operation! The cylinder stop does make a distinct click right before the hammer releases so I will stop worrying

I was able to straighten the extractor rod between a brass plate and nylon mallet but the knurling is still less than perfect. Runout is gone on the extractor rod though, and since my cylinder concerns shouldn't have been concerns, I think I will head to the range tomorrow.

As far as it being accurate, I am not...so that'll take a while to check!