End-Shake Tolerences

[snubbiefan]

I have heard lots of numbers and I guess I should call Smith, but I have all the experts right here on the forum...so.

When does end-shake in a 22 caliber revolver become a problem? The gun shoots great, it's as accurate as I am and doesn't spit, but the end-shake is close to .007-.008. This being a 22....hardly any danger of stretching the frame...I would suppose?

The story is that I acquired a spare cylinder and yoke and fitted it to see what would happen. Yes...I know the "word" is that this should be factory fitted. If I shim this thing back closer to like .003 or .004 end-shake, I will wind up with a sizable .010 to .012 BC gap and I do not want to spend any money to have the barrel re-fitted.

Any thoughts?

 

[500 Magnum Nut]

If it starts to misfire or have carry up issues then fixing the endshake is first on your list of repairs.

 

[scooter123]

IMO you should just shim it and deal with the larger B/C gap, with a 22 caliber I'd consider 0.003 or 0.004 inch tolerable but any more and I'd correct it. No, it won't stretch the frame, however with that much slop I do believe that it will start peening the end of the yoke tube and it won't be long before the cylinder is slapping the barrel. On the other hand, that larger B/C gap won't have much effect on accuracy and with the low pressure of the 22LR the only real issue is a need for more frequent cleaning of the leading it'll cause. Bottomline, it's wiser to have to clean the gun more often that beat the end of the cylinder against the barrel.

BTW, I have a 617 no dash with a 0.010 inch B/C gap and it'll shoot under 2 inches for 24 rounds at 35 yards on any day I'm up to shooting that well. So I know from personal experience that a wider than optimum B/C gap really doesn't hurt accuracy that much. Bottomline, fix that end shake before you start beating up your barrel and cylinder. Note, I'd shim it to produce between 0.001 and 0.002 inch of end shake because tighter is better in this area even if the resulting B/C gap is a bit wide.

 

[snubbiefan]

Good information folks. I do not own a revolver that has anything greater than .005 to.006 BTC gap and I have read where a larger BTC gap may not be destructive in any way....other than the issue mentioned concerning cleaning. I am pretty sure I'll be shimming it for end-shake.

The spare cylinder and yoke were cheap....heck, I just had to try it and see what would happen. The only detrimental affects I have noticed appears to be excessive end-shake.

I am just one of those folks that likes to try and figure-out things for himself and do my own fixes, but I try and stay away from "Bubba" territory. I believe shims will be in order here and I'll be good-to-go.

 

[Tyrod]

As an aside, I've been putting the barrels on my Dan Wesson with the supplied .006" feeler gauge for going on 30 years now. I can't say that I've ever had an issue except for wearing a feeler gauge out. It's prolly .004" now. And it's the one out of 3 feeler gauges I use most often.

 

[snubbiefan]

I need to add some information here that I should have stated up-front. I think it may be beneficial to those that continue to ask and worry over the aluminum cylinder models.

This is a model 317 in question. I picked-up a complete set of used "innards" for a 317. In these parts was everything but the frame and included the cylinder and yoke assembly. I think I have discovered the wear-point that will begin to show-up in the aluminum cylinders and it won't be from bore-wear....it will be from interior bearing surface wear. Both yoke assemblies from my gun and these used parts were dimensionally identical and the end-shake manifested itself with the used cylinder over either yoke assembly. So....the wear-area in this aluminum cylinder is at the base of the cylinder and not the yoke assembly. A shim will fix this problem and even provide a harder bearing surface where the yoke-rod meets the interior of the cylinder.

This may be worth mentioning in the threads concerning aluminum cylinder longevity. It's not the bore-wear of overall cylinder strength....it's the wear where the cylinder meets the yoke-rod.

 

[tomcatt51]

This may be worth mentioning in the threads concerning aluminum cylinder longevity. It's not the bore-wear of overall cylinder strength....it's the wear where the cylinder meets the yoke-rod.

The same applies to the carbon steel and stainless cylinders. The end of the yoke will wear a groove in the cylinder surface. You need to fix the groove before shimming. If you don't, the shim gets trashed and usually the shim gets blamed. It's like blaming the Wolff reduced power mainsprings for mis-fires when the the problem is a too short strain screw.

When you have one .002" shim fix .006" endshake, you know there's a groove. If you true the surface the shims do work well as a bearing to prevent the groove from forming and hold endshake in tolerance much longer than yoke stretching.

 

[snubbiefan]

That makes a HEAP of sense and I can actually see (or imagine) the groove down there at the end of the cylinder....I had looked in there before you made this post.

Just as an aside...I did notice on the used yoke two "stretch-marks" where the tube had been adjusted. So...this was either done at the factory or by a smith somewhere along the line. Surprisingly....it is exactly as long as the un-touched rod on my gun.

How may times can you stretch a yoke tube?

 

[Fkimble]

Powers makes a hand tool to square the end of the yoke but I don't see anything like it to cut the inside of the cylinder itself. What is the best/easiest way to clean up the inside of the cylinder? And I just replaced a .002 shims to fix .005 endshake in each of 2 28-2s. So I'm looking at either fixing the groove or replacing the shim sooner than later or both?
I suppose I could use the yoke end tool and remove just enough to allow a .004 shim to fit, this should be thick enough to last much longer than a .002 shim before sellf destructing?

 

[snubbiefan]

Wonder if it's possible to peen it back down and then add a thin shim on top of that?

 

[tomcatt51]

Powers makes a hand tool to square the end of the yoke but I don't see anything like it to cut the inside of the cylinder itself. What is the best/easiest way to clean up the inside of the cylinder?

A "W" drill bit goes into the cylinder just right. I cut the shank end square and glue on a piece of wet or dry sandpaper, 220 or 320 grit, to square the cylinder surface. Water works fine to keep the sandpaper from loading up.

I like the .004" shims best and set even new guns up to use a .004" shim. Then add as necessary, put the .004 in last.

 

[snubbiefan]

I KNEW somebody would be along with the answer!

 

[TAROMAN]

A "W" drill bit goes into the cylinder just right. I cut the shank end square and glue on a piece of wet or dry sandpaper, 220 or 320 grit, to square the cylinder surface. Water works fine to keep the sandpaper from loading up.

I like the .004" shims best and set even new guns up to use a .004" shim. Then add as necessary, put the .004 in last.

Thanks, man. This worked the trick.
Faced off the end of the drill in my lathe and super glued the sandpaper to it.
Trimmed it and went after the cylinder.
A couple sandpaper runs later, and I finished it up with some valve grinding compound.

 

[ViperR]

I dressed down a Dremel reversed cone grinding bit to just slide in the cylinder. I attached it to tap wrench and making sure it laid flat on the grooved area, I twisted and ground away the groove. Cleaned it up with lapping compound and cleaned and dried it good with brake cleaner (GunScrubber). A .004" shim was a perfect fit and now have .002" end shake. Make sure you lube all mating surfaces before assembly. The yoke end was fine, but I polished it a bit with lapping compound.
I was getting misfires in my rimfire, but now after 1,000 it's still good.

 

[snubbiefan]

This must speak volumes for the 317 and maybe the 63. I swear the end-shake I had when I started this thread about this old used cylinder was .008 and better. If you allow for say.....004 BTCG...I can get a .012 feeler in the gap with the cylinder pushed back against the recoil shield......AND...it still goes bang every time.

 

[tomcatt51]

I dressed down a Dremel reversed cone grinding bit to just slide in the cylinder.
The yoke end was fine, but I polished it a bit with lapping compound.
I was getting misfires in my rimfire, but now after 1,000 it's still good.

What works, works. I don't like going in with something that will cut the sides of the yoke bore vs just the face.

Sometimes the end of the yoke is fine. I use dykem (sp?) or just a sharpie and check the contact pattern.