M66 bolt (or cylinder stop) engagement

[Topgun]

My 66 is a .....bit..... sloppy in battery. Wondering..... seems like the bolt engagement in the cylinder cut is not real deep.
Could the depth of the engagement have any effect on lockup in battery?

IF.. I stoned the TOP ONLY of the part of the bolt that is INSIDE the frame (NOT the top of the bolt that engages the cyl) would it allow the bolt to rise a bit further in the frame?

It ....seems..... that if I don't touch the lower part of the bolt notch (inside) where the trigger engages it to pull it down and out of lockup, then no matter how high the bolt rode, it would still pull it completely out of engagement so it would not drag on the cyl .....or..... stay too high to allow it to revolve.

Is this correct?

Can I stone the internal part of the bolt to get more engagement in the cyl notches?

 

[Badger Arms]

Before you do that, you might consider CAREFULLY removing the sideplate and doing a thorough cleaning. It might be that some manner of fouling is preventing the bolt from fully seating.

 

[bountyhunter]

Clean it first, but it is probably normal wear. The "wobble" in lockup (battery) is inherent as wear accrues at several places:

1) The inertia of the cylinder rotating and catching the bolt peens the frame on the RHS in the slot the bolt pops through.

2) Same effect peens over metal in the cylinder slots the bolt pops up into.

3) Wear in the frame slot that the hand comes through means it does not apply as much force to the star (end of ejector) to hold the cylinder tight in lockup.

One thing I can say: stoning on the bolt is going to screw it up. You can fit an oversized bolt (I did it on my 686), but unless you are an experienced smith on these guns, don't try it.

Can I stone the internal part of the bolt to get more engagement in the cyl notches?

No, but check one thing: it is possible that the metal on the frame slot (that the bolt comes through) which gets peened may be holding the bolt from rising all the way up (I doubt it, but it's possible). If so, you can smooth the underside of the frame below the slot to allow the bolt to come all the way up.

 

[Topgun]

Worst part is that it is almost a new gun. Have had for years but mostly as the shop gun before we retired.
So I would imagine a maximum of .....maybe.....500 rounds and MOST being .38 wadcutters.

It is also only 2 holes that are what I find too loose. No lead shaving. Accuracy OK but not great. Looks OK from looking per Mike Irwin and my own bonsai wire hook check.

It's CLEAN. BOY is it clean. It was just a wild idea that I had from looking at the depth of engagement and it isn't very deep. Can't force it out of battery so it's deep .....enough. I guess.

Probly should just leave it alone and shoot it.

But that's no fun. Gotta .....TINKER..... to make a gun behave.

 

[bountyhunter]

It is also only 2 holes that are what I find too loose.

Either:

a) The cylinder cuts on those two positions have become enlarged (or were never right)

2) the star blocks associated with those two positions are damaged (or were never cut right)

 

[Topgun]

Bountyhunter...


Think you right.



Have even ......t h o u g h t........ of peening a small tink on one or the other.

No. Shoot the damn thing.
B-b-b-b-but.
Enough sniveling.
Shoot the damn thing.

 

[bountyhunter]

If it is the cylinder slot being peened, the factory can squeeze the metal down and make it move over (saw a picture of how they do it). It it is the star blocks, they would have to do a new ejector. Fitting those is not trivial work. BTW: I shot my 686 until the cylinder probably had .030" wobble in lockup at every hole (I guess about 25k rounds fired?). I didn't notice any difference in accuracy. I fitted new wider bolt to take most of the wobble out just because I figured it deserved it (my first wheelgun). Still shoots <2" groups freehand at 25 yards.

 

[Jim K]

Hi, Topgun and guys,

I hate to disagree with such distinguished company, but on a S&W (unlike a Colt) the hand has very little to do with the cylinder lockup once the cylinder is locked. In fact, the hand slides up past the ratchet as the cylinder reaches alignment with the barrel and most S&W revolvers are not rigidly locked when cocked (there is almost always a slight rotational movement). S&W says that rigid lockup is not necessary and that (within limits) the bullet itself will line up the cylinder with the barrel. They also say (correctly) that the Colt hand can actually push the cylinder out of alignment once the gun takes on some wear.

In most cases, it would be perfectly OK to take a bit off the cylinder stop in front of the stop lug itself. In fact, if you look you will see that there is a little pad there to allow just such fitting and the stops are fitted that way at the factory.

If the stop spring is OK and there is nothing else you can find wrong, try a bit of stoning at that point. Work carefully, but the worst you can do would be to let the stop come up too far so the trigger would not engage it. Since the stops are fairly cheap $8 or so, you can't do much damage.

Jim

 

[bountyhunter]

most S&W revolvers are not rigidly locked when cocked (there is almost always a slight rotational movement).

That is true of their newer guns. Check an older one with low mieage and you will see they used to lock up tight (no wobble at all). Part of the reason the new ones wobble in lockup is they no longer have the pins from the ejector star into the cylinder. The new ejectors are "angle cut" to apply rotational torque. That also gives them a bit of play.

The main reason new SW's do not lock up snug is that they are not properly fitted. I have inspected more new SW's than I could count, and a few have a snug lockup, most don't. Some of the new PC 627's are loose as are their 629's... and some are tight. The 66 I ended up buying had a snug lockup on three cylinder positions, and a few thousadths wobble on three. Old wheel smiths know about the process called balancing and know that means the guy who did this one didn't do it right. But, it had the best trigger and was tighter than the other dozen 66's here in town so I bought it anyway.

In fact, the hand slides up past the ratchet as the cylinder reaches alignment with the barrel

correct, but the hand is still incontact with the star ratchet (along the RHS). That is one point the cylinder is held in lockup. The other two are: the pin that goes into the recoil shield (that the cylinder turns on), and the stop bolt in the cylinder notch at the bottom. Wear at the frame slot (where the hand comes through) will increase wobble, but the main culprit is the peening of the cylinder notch as well as the frame slot edge where the stop bolt pops up. Rotational inertia of the cylinder beat on those every time the cylinder turns.

S&W says that rigid lockup is not necessary

That is what they say NOW..... strictly speaking, it is not necessary. Every revolver "loosens up" on cylinder wobble as it wears on the points I mentioned. Buying one that already wobbles is like buying a new set of tires that somebody already drove for 10,000 miles.

In most cases, it would be perfectly OK to take a bit off the cylinder stop in front of the stop lug itself. In fact, if you look you will see that there is a little pad there to allow just such fitting and the stops are fitted that way at the factory.

True, and that was my point earlier: there are several critical fit points on a stop bolt and the factory fitted them to the trigger and cylinder when they built the gun. Stoning it likely means you are screwing it up, especially since the original poster said:

"It is also only 2 holes that are what I find too loose."

That means the stop is not the problem. It's either the cylinder slots or the ejector star.

try a bit of stoning at that point.

At least read the Kunhausen manual on SW first to understand the relationships of the various surfaces of the stop.

 

[Jim K]

Hi, Bountyhunter,

I am about willing to bet that I have handled more old S&W's than most folks, and most of them never really locked up tight, even from the factory. That S&W comment about alignment by bullet was made at the factory around 1957, so it is not "what they say now".

You are very correct about the other factors involved, but that was not really the question Topgun posed. He said that the cylinder stop was not entering the cylinder notch far enough; I think my suggestion was quite correct for solving that problem. It is not uncommon for S&W's to have that problem due to the fitting (or lack of it) we both mentioned.

As for only two holes being "loose", you indicate that cannot be due to the cylinder stop not coming up high enough. All I can say is maybe. If the stop is coming up short, and not entering the notch fully, the battering you mention will enlarge the notch on the outer edge even more than normal, so it is not, IMHO, unlikely that some notches will wear more than others. In any event, there will be some play in that cylinder. The stop has to have room to move; the extractor (ratchet) has to be free to move to eject cases; the hand has to be free to retract. If everything were as tight as possible, nothing would work, hardly a desirable situation.

BTW, do you remember that S&W used to insert little pieces of hardened steel in the cylinder at the side of the notches? That solved the wear problem, but they decided the cost was just too much for a minor improvement. Maybe that was when they started to say that the bullet would do its own alignment.

Jim

 

[Topgun]

First, let me solve ONE problem in answering the "problem" (if indeed a problem even exists)
(Jeez, I may go into politics on THAT sentence)
There is NO peening ANYWHERE. The star looks very crisp and unworn.
As I said, there is VERY little use on this gun.

The K frame cylinder shouldn't peen much with not much use due to its light weight compared to the N frame cyls. And it hasn't. NO evidence at all of any peening from being stopped.

My.........theory........ is that this fairly new gun is a product of fast manufacturing and that some of the SLOTS are microscopically different from the rest.

ADD to this that the bolt does not .....appear.....to engage deeply at all and could be FURTHER evidence of sloppy fitting when new.

That was my reason for asking about taking down the front part of the cyl stop as even minor relief looks to be magnified at the stop itself by VERY small adjustment of where it hits the frame.

It......LOOKS.....like if the stop went just a wee bit further into the slot that it would compensate to some degree any variation in cyl cut dimensions.

As it is NOW, it amazes me that it is NOT peened. That stop is ...j u s t...into the slots on all holes. Enough to stop it decisively, but not ...q u i t e.. enough.

If that makes sense.

I haven't had the stop out yet. I know how it works. I have had it pressed down enough to check for grit or crap above the part of it I am thinking about putting on a pedal powered axe grinding stone (kidding).

It shore LOOKS like a lil more "sticky-inny" would alleviate the "problem."

...Now if I can just PRY off the sideplate one more time without bending it too much more than I have...... (kiddin again)



P.S. Wouldn't it be great if S&W fitted a carbide RING to the cylinder with the cuts in THAT? Probly be easier than fitting the little wedgies.

P.P.S. I think I'm beginning to HATE every gun made since about 1960.

 

[bountyhunter]

It......LOOKS.....like if the stop went just a wee bit further into the slot that it would compensate to some degree any variation in cyl cut dimensions.

Take the bolt out and "hand test" the fit into each slot and see if two are too tight to let the bolt seat. If they are, those two slots need widening (you can cut on the bolt if you don't mind the extra wobble). If it drops properly into every slot, something else is the problem.

 

[bountyhunter]

I am about willing to bet that I have handled more old S&W's than most folks, and most of them never really locked up tight, even from the factory.

Those are the ones I leave in the case for somebody else to buy.

That S&W comment about alignment by bullet was made at the factory around 1957, so it is not "what they say now".

OK, I realize the taper on a forcing cone is there for a reason.... I'd just rather have a new gun that is fitted right.

BTW, do you remember that S&W used to insert little pieces of hardened steel in the cylinder at the side of the notches? That solved the wear problem, but they decided the cost was just too much for a minor improvement. Maybe that was when they started to say that the bullet would do its own alignment.

What they need most is some re-enforcement at the frame slot where the bolt pops up. On my 686, it peened the crap out of that edge and required an oversized bolt eventually.

Funny story.... SW no longer makes or sells the oversized bolt. I called the factory to ask about one. When the guy told me they didn['t have them, I asked him how they could fix guns that were peened over at the frame?

His reply: "That's a good question....."

Numrich still has them for now.

 

[Jim K]

Hi, Bountyhunter,

I am sure there are S&W revolvers that have absolutely no play whatsoever in any parts. If I ever find one, I'll be sure to send it on.

Jim

 

[Topgun]

Jim, if you need a reliable source of "no play" Smiths, try under big city bridges.

 

[bountyhunter]

Hi, Bountyhunter,

I am sure there are S&W revolvers that have absolutely no play whatsoever in any parts. If I ever find one, I'll be sure to send it on.

Jim

,

If you read my posts, you will find I stated that a properly fitted new SW had snug fit (zero rotational cylinder play) in lockup. That does NOT imply there is zero play between all parts, in fact it does not imply there is zero play in the fit between ANY two parts. The point is, the play is lockup can (and was) routinely fitted for zero play quite easily on older guns by properly balancing the fit of the blocks on the ejector star to the hand. It was not magic and it was not brain surgery. But the key word there was "fitted". That word no longer is in the SW dictionary, where the advent of MIM has brought the mindset that all parts drop into the gun and it flies out the back door without any fitting at all.

As for "fits" that have no play: read the Kuhnhausen spec on what the proper clearance is for front-rear cylinder play (end shake): it is ZERO to one thousandth of an inch (0 - 0.001").

The point of my post is twofold:

1) You as a consumer, are not required to buy a gun that is not properly fitted. In fact, I would say if you shop for a new SW without feeler gauges and a range rod, you're nuts. I routinely see barrel cylinder gaps between .010" and .015" on new smiths.

2) The standard of fit between new guns today and new guns ten years ago has nosedived. That means very nice used guns are (in many cases) better guns than the new ones being shipped. Food for thought.

 

[JNewell]

I'm not Jim and don't play him on TV, but zero endplay is not the same as zero rotational play. I don't have Kuhnhausen's book here, but I'll take a look at what he says about that tonight. IIRC, S&W HEs aren't designed to lock up with zero rotational play (unlike, for example, Colt I-frames).

 

[bountyhunter]

IIRC, S&W HEs aren't designed to lock up with zero rotational play

I might believe that if I hadn't owned three of them that did. One is a model 10 (from the 70's), another is a 66 and a 686 from mid 90's vintage. Snug lockup on a SW was not that difficult to achieve. It is not essential to accuracy, it just showns the gun is properly fitted. All wheelguns loosen up as they wear, and eventually have to be re-worked. Point is, they don't have to start out loose when new.

 

[Dave Sample]

I have only tuned a few dozen of these so I will not put a dawg in this fight. I will just say that I agree with Jim Keenan 100%. S&W 66's were my favorite duty gun for years when I could not carry a 1/2 90. I do not have any S&W's now and they are not allowed in the yard since they rolled over for Slick Willie. I gave all my Smith tools away to Don Williams and will never tune another one as long as I live. Someone has to take a stand when these things happen and I have always done that. I realize that it did not make any difference to anyone but me, but that's OK. I feel good about it. If it works, don't fix it!

 

[JNewell]

I'm sure tight ones get out of the factory, but I don't believe it's inherent in the design - unlike a Python, for example. In theory, depending on how tolerances stack up, it could even be a bad thing. (Cylinder could lock tight but out of alignment with the forcing cone and bore.) I am going to apologize for not getting to K's book (still mean to, if only for self-education on this issue) -- am getting killed at work this week. :banghead:

 

[bountyhunter]

.

I'm sure tight ones get out of the factory, but I don't believe it's inherent in the design - unlike a Python, for example. In theory, depending on how tolerances stack up, it could even be a bad thing.

Folks, you miss the entire concept of differentiating between a "tolerance" fit and a "fitted" fit. The former requires you leave enough slop to allow the parts to drop together without an interference fit, the latter does not.

The cylinder end shake is (or was) a fitted fit... based on my examination of the crane in my newest gun, it still is. The end of that crane tube was clearly swaged (lengthened) and then machined to precise length to get the proper end shake (clearance). I would have preferred if it was cut right the first time, but so be it.

The cylinder lockup USED to be a fitted fit and the fitting method was in the blocks on the ejector star. Anybody who has taken the SW armorer's school knows how it is done. And, if properly done, it leads to a snug fit with zero (or imperceptible) rotational play even though none of the individual pieces have to be held to a ridiculously tight tolerance. Old smiths came with this, new smiths don't. Argue about whether it's worth the money, but it's a fact it can be done and the way to do it is well known... and used to be the standard of manufacture.

 

[JNewell]

No one's missing the point. It just isn't required for the design to work to spec. I've just taken a good deal of time I'd rather have spent doing something else going through Kuhnhausen's book. There is a lot of attention to issues like endshake (as you note), but if there is more than a passing line or two on rotational cylinder play, I missed it. Contrast his discussion of the I-frame. They are fundamentally different designs.

Can a S&W be set up this way? Sure. But I'm not sure you want it that way, except for shooting on a square range at bullseye targets. If you get a bit of burned powder crud or some other bit of dirt on the star, the zero tolerance gun can turn into a zero function gun. Can you set up a M1911 really tight? Sure. But you don't even have to get into the field to find out what happens...take any pistol course and watch without even going outside.

I'm done. You get the last word.

 

[bountyhunter]

If you get a bit of burned powder crud or some other bit of dirt on the star, the zero tolerance gun can turn into a zero function gun.

If you did much comp shooting with wheelguns you would know the #1 reason they become "zero functionsl guns" during shooting is when hard carbon falls onto the ejector rod as the cases are ejected, then the crud accumulates UNDER the head of the star and can cause binding precisely because the end shake spec is .001" or less. Why must it be a tight spec? because if the cylinder is allowed distance out from the recoil shield, it gets a "running start" when the round fires and the case expands and drives the cylinder back into the shield. A loose end shake will end up with the cylinder beating the recoil shield all to hell.

So, the actual "zero fit" that causes jams with careless reloading is the one which is required by the SW design (end shake).

Crud on the outside of the stars will NEVER cause a problem in a gun even with a snug lockup because the hand pushes the star block up then slides along it and would sweep out anything in it's way. It is the "trapping" action of the star head against the cylinder face that can make a hard carbon pad which will bind a cylinder or even bend a crane if it is forced to close.

 

[bountyhunter]

Can you set up a M1911 really tight? Sure.

That's a separate myth: that a 1911 has to rattle to be "reliable". Read the Kuhnhausen manual on the correct fit for a 1911 (barrel/slide/frame) and you will find they say it is when the barrel in lockup rests with the lower lugs on the slide stop cross pin (NO PLAY) and the upper lugs inserted into the slide cuts with the barrel snug against the slide. This is called the "three point support" as the two lower lugs rest on the cross pin and the top of the barrel rests against the slide. I have two hand made 1911's (STI) that are 100% reliable and they both lock up dead tight (barrels have absolutely no play at either end in lockup). The mass makers of 1911's do not fit their guns this way because hand fitting is too expensive.

I never said it is essential for a gun to be properly fitted for it to work: I simply pointed out that are basically two ways to fit a gun: the right way and the other ways.

 

[bountyhunter]

I've just taken a good deal of time I'd rather have spent doing something else going through Kuhnhausen's book. There is a lot of attention to issues like endshake (as you note), but if there is more than a passing line or two on rotational cylinder play, I missed it.

You also apparrently didn't read my posts because nowhere did I say that Kuhnhausen covered the technique of "balancing" or fitting a star, or fitting up a gun for zero rotational play. It is too complicated and they do not cover it. I directed the original poster to Kuhnhausen to understand the relationship of the surfaces of the stop bolt: I said:

At least read the Kunhausen manual on SW first to understand the relationships of the various surfaces of the stop.

Here is what I said was in Kuhnhausen:

As for "fits" that have no play: read the Kuhnhausen spec on what the proper clearance is for front-rear cylinder play (end shake): it is ZERO to one thousandth of an inch (0 - 0.001").

I did give my opinion which I stand by:

If you read my posts, you will find I stated that a properly fitted new SW had snug fit (zero rotational cylinder play) in lockup.

You will find many of the new PC guns are fitted up, and some are not.

I also never said a gun could not shoot accurately with cyl play, because they can. The bullet "squares up" the cyl alignment as it enters the forcing cone. I'd just rather have one that is right when it starts out because that means it will be longertime until I have to overhaul it from the wear points loosening up.