"Never ever, ever, ever, ever, ever, ever....."

[armorer951]

GunBlue490 passes death sentence on end shake shims, AKA: "washers".

Inspection tips video. End shake and repair mentioned at the 21:00 minute mark. He obviously hates shims, with no qualifiers.


How to Inspect a Smith & Wesson Revolver ~ Know Before You Buy! - YouTube


Carter

 

[stansdds]

Interesting. I was curious as to his logic for not using shims, so I scrolled through the comments and found this entry.

Colonel K:
You said not to put washers in the revolver to reduce end shake. Are you referring to the thin shims used in cylinders and yokes?

GunBlue490:
Yes. They eventually break down and the floating parts can cause serious problems, most especially an unexpected complete stoppage in a defensive gun. These are correctable issues that are accomplished by the factory.

I had wondered how they would withstand the impact forces during firing. I'm thinking these might be fine for range toys, not fine for serious use revolvers. Sort of like nylon shock buffers in semi-auto pistols.

 

[SS336]

Ok, should I be worried?
I just looked and the one revolver that has one hasn't fallen apart yet.
Is it just his opinion or is this a "thing" now.
I respect your opinion, what go you think about endshake washers?

 

[K Harris]

Jerry Kuhnhausen has no problems with them.

 

[WR Moore]

Well, the factory fix involves stretching the yoke barrel. This reduces the cross section that supports the fore and aft loading during firing. Thereby reducing the strength of the part. Is it a significant reduction? Dunno, but the shims work.

I installed shims in my model 29 in the 1980's and they haven't failed or impaired function yet.

 

[VaTom]

GunBlue490 passes death sentence on end shake shims, AKA: "washers".

Inspection tips video. End shake and repair mentioned at the 21:00 minute mark. He obviously hates shims, with no qualifiers.


How to Inspect a Smith & Wesson Revolver ~ Know Before You Buy! - YouTube


Carter

Watched the entire video on Friday. Thought it was very good information. On several occasions he mentions that the revolvers he was showing were designed as "combat firearms".
Such firearms must be totally reliable, shooting the first time / every time. Anything that could remotely cause a malfunction is unacceptable. As someone who carried a Model 10 and Model 64 for years as a LEO I agree with him.

He is old school. When he showed how to properly hold a revolver when reloading it took me back to my LEO basic training days in 1976. That is how we were taught! Still do it. With many of newer shooters never handled a revolver the information is in the video is good for those buying their first.

 

[armorer951]

Stretching of the yoke barrel is, or was, the factory solution to excessive end shake on the yoke barrel. Peening the end of the yoke barrel was also a technique used, and was taught at the armorers school. I would suspect that nowadays, the factory repair folks would simply replace the yoke entirely if parts were available.

I haven't seen any S&W sponsored prohibitions or "warnings" concerning the use of shims to correct excessive end shake. I say excessive, because if the front and rear gauges in the gun are correct and in spec, then end shake is a non-issue. I have no personal experience with installed shims "coming apart" inside the assembly as he indicated would happen, although this would certainly be a possibility, especially when/if proper maintenance is neglected. During 40+ years, I have certainly seen many neglected revolvers, including those used by people whose lives depended on them.

If due caution and attention is used, shims seem to be a viable correction for this common problem:

The interior bearing surface inside the cylinder yoke cavity should be prepped properly, and the end of the yoke barrel should also be squared to 90° (confirmed to be square) at it's end with a facing cutter, and lightly polished with crocus cloth or similar. This enables the forces on the shim to be distributed uniformly.

Stacking thinner shims to take up larger spaces inside the assembly should be avoided. If the space in the assembly needs to be closed .004", then a .004" shim should be used, not four .001" ones. Common sense. Follow the instructions supplied with the product, if there are any.

After installation, regular inspection and maintenance should be performed to ensure that the integrity of the repair. Regular cleaning and re-lubrication is also a must.



Carter

 

[Inusuit]

I've successfully shimmed several S&W revolvers including two that are used as class guns for NRA Basic Pistol. Several thousand rounds with no problems.

 

[Protocall_Design]

I prefer the stretching method, as it keeps everything one solid piece. Also, it's easier to do since you don't have to disassemble the cylinder assy. to do it.

I have seen a lot of guns with shims in them and not a problem with them. I feel that either way, done correctly, is a viable fix.

I don't like the end peening method because that makes a bunch of high spots on the end, rather than a smooth, continuous, face for the cylinder to ride on.

 

[pantannojack]

What is the alternative? Take it to a GS and 16 months later they still don't remember that you brought it in for service?

 

[2152hq]

Take one of the shims,,place it on a smooth steel surface.
Place a smooth flat faced punch squarely on the shim.

Now pound on that punch with a large heavy hammer. Keep pounding untill the shim itself breaks up into tiny pieces that would cause the revolver to stop firing.
The shim is contained down in there. I guess if soft enough and hammered on long and hard enough it could compress. But it would have to 'grow'. That metal has to go somewhere and out to the edges is where it will go and slightly curve inward where it disturbs nothing.

OTOH, a shim made from hardened HT steel could possibly shatter if too hard I Guess. That could be a problem perhaps.

GunBlue490:
Yes. They eventually break down and the floating parts can cause serious problems, most especially an unexpected complete stoppage in a defensive gun. These are correctable issues that are accomplished by the factory.

States that they do eventually break down....He must have some proof of this?
Does 'breaking down' mean shattering and breaking into pieces as he claims?
Or does it mean that the shim itself becomes battered and thinner just like the original surface contact points and get loose once again.

That the 'issue' is correctible by the Factory is certainly true.
They will likely fit a new Yoke for you.
They don't mess with stretching the tube anymore I wouldn't think.
Labor isn't cheap.
Parts replacement is.

I think it's one person's thoughts about what could happen. What may have occured with the wrong material used for a shim in someones project gun perhaps.

But with the many thousands,,maybe more in use and no reported problems, I don't think shattering yoke shims are about to raise their ugly heads in the DA revolver world and bring them all to a terrible halt.
All at the most intense moment of need.

 

[smoothshooter]

Interesting. I was curious as to his logic for not using shims, so I scrolled through the comments and found this entry.



I had wondered how they would withstand the impact forces during firing. I'm thinking these might be fine for range toys, not fine for serious use revolvers. Sort of like nylon shock buffers in semi-auto pistols.

Wouldn't the brass case head transfer a lot of the rearward thrust to the firing pin bushing area o the frame when the gun is fired?

 

[armorer951]

During recoil, the end of the yoke barrel is impacted by the interior boss at the bottom of the yoke cavity in the cylinder. Recoil causes the frame to go rearward, while the cylinder rides on the yoke, independent of the frame and tries to remain stationary.

This repetitive impact force to the end of the yoke barrel during recoil is magnified by the caliber of the gun, the weight of the cylinder, and the end shake space provided in the cylinder assembly.

 

[pantannojack]

During recoil, the end of the yoke barrel is impacted by the interior boss at the bottom of the yoke cavity in the cylinder. Recoil causes the frame to go rearward, while the cylinder rides on the yoke, independent of the frame and tries to remain stationary.

This repetitive impact force to the end of the yoke barrel during recoil is magnified by the caliber of the gun, the weight of the cylinder, and the end shake space provided in the cylinder assembly.

So temporary expansion of the cartridge case at firing does not grab the cylinder and thrust it rearward to the recoil shield minus head space?

 

[pantannojack]

What is the alternative? Take it to a GS and 16 months later they still don't remember that you brought it in for service?

I think the answer is to get the tools and do it your self. I mean stretch and face the yoke.

If you love a WOMAN you can't keep your hands off her. The same for a revolver or a dog.

 

[pantannojack]

During recoil, the end of the yoke barrel is impacted by the interior boss at the bottom of the yoke cavity in the cylinder. Recoil causes the frame to go rearward, while the cylinder rides on the yoke, independent of the frame and tries to remain stationary.

This repetitive impact force to the end of the yoke barrel during recoil is magnified by the caliber of the gun, the weight of the cylinder, and the end shake space provided in the cylinder assembly.

I can imagine that the yoke does not shrink/compress under impact square to the axis of the bore line. Therefore simply adding shim after shim can actually bend the yoke. Might a abrasive shim wear off the high points under rotation?

 

[armorer951]

This is a very complex issue involving several moving parts and consequently, my understanding of the process is limited. Two things for sure.......I am certainly old, and I am certainly not an engineer.

My understanding is as follows:

In modern cartridge revolvers, the rearward motion of the cylinder occurs during the initial ignition and pressurization phase of the detonation (prior to recoil) and does not result in a "heavy" impact of the cylinder against the breechface. This is demonstrated by the lack of impact damage on the breechface (or the surface of the extractor boss) by the boss in the center portion of the extractor. This boss around the center pin in S&W revolvers provides the only contact site of the cylinder assembly against the breechface.

The damage and "peening" at the end of the yoke barrel and bearing surface at the bottom of the cylinder yoke cavity happens during the recoil phase of the frame subsequent to detonation. During this phase, the end of the yoke barrel batters the bottom of the cylinder yoke cavity. The yoke is fixed, and is a part of the frame and moves back with the frame under recoil.

To say it another way....the cylinder, which moves freely on the yoke barrel (front to back) tends to "stay stationary" on the yoke while the frame moves back under recoil forces. As the frame and yoke move rearward under recoil, the end of the yoke barrel impacts the bearing surface at the bottom of the cylinder cavity.....to the extent that motion is allowed by the required end shake in the cylinder assembly.

This unavoidable impact and battering or "peening" of the yoke barrel occurs each time the revolver is fired. Other damage occurs to other parts involved, but this describes the end shake issue we are all trying to understand and repair, if needed.

 

[chief38]

IMHO there is no "absolutely perfect" way to correct end shake without parts replacement. If the Yoke is stretched back to spec with the repair tool that resembles a tubing cutter (essentially weakening the tube), the yoke will eventually get pushed back and "shrink" - hence end shake will eventually return. If shims are used, there is a minor risk of them wearing and small debris could be generated. As the shims wear, end shake will increase again. The use of shims will proportionally increase the barrel / cylinder gap.

Now the practical and realistic side. Excessive end shake must be repaired for proper functionality. I don't care much for stretching the Yoke and much prefer using shims to fix the issue. If quality made shims are used, the risk of them coming apart as GunBlue490 suggests might happen, is almost a non issue. I have repaired end shake with the use of shims several times and after 2 decades of shooting there are absolutely no issues at all. Yes, barrel /cylinder gap was increased slightly, but it is still to acceptable tolerances and does not affect function of the revolver. Quite honestly I have never seen shims "come apart" and have not seen any issues at all. Heck - shoot any gun enough and something has to eventually wear! Given the option of stretching the yoke or using shims, I prefer the shim method and have never had issues with their use. At this point, I doubt too many Gunsmiths still use a Yoke stretcher and would also prefer using shims. Again, other than replacing parts, there is no absolutely perfect way, but I feel the shim method is just a better way to go and will usually last decades of use with normal pressure ammunition that the gun was designed for.

 

[chief38]

BTW, I have watched many of GunBlue490's videos over the years. I agree with some of what he has to say and disagree admittedly other times. Everyone (even sometimes Certified Gunsmiths themselves) often disagree on how to get something done. Most Gunsmiths (as other Tradesmen) usually attend classes, courses and work as an apprentice under an experiences GS and that is where they get their training, experience and are taught to fix something a certain way. As I have come to realize as I've gotten older, there are sometimes alternative methods that are as good as or even better than conventional methods but for one reason or another do not fit a conventional repair method. Some reasons for this might be because it may just not be able to be done by some or may take so long that a reasonable profit could not be realized.

ie: When you bring your car into a repair shop because the starter is broken, water pump is broken radiator is leaking, they will just replace said part. It's not necessarily because the original part can't be fixed, it is because many mechanics today are incapable of actually repairing the original part and even if they could the time it would take would be too long to make a profit. That doesn't mean that actually repairing a broken part is the incorrect way to go! Same thing sometimes with guns.

Sorry if I've drifted a little from the original topic, but I did want to point this out. There are times I have repaired Revolvers in a way most professionals would never do because the job took so long and was so precise there would be no room for them to make money on that job. That doesn't mean my repair is not as good and could even be better.

GunBlue490 has his own opinions, methods and procedures. While I do disagree with him sometimes, I do respect his opinion most of the time.

 

[oink]

I have a stretcher and a fair supply of shims. The stretcher is easy and I suspect any weakening is negligible and not an issue. To me the shims just create another place for crud to collect eventually become a cleaning issue. Probably not much of an issue if you only shoot clean jacketed ammo. Lead, dirtier powder and alox/bees wax lube and it will get in there eventually.