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Jumping Frog wrote:

olafpfj wrote:I may be well out of my depth on this comment but here goes...

While it is CLEARLY not correct I don't think that it is dangerous. I would like to hope that the safety tolerances are such that, while not correct, is still OK.

No, it is dangerous. Speaking as a Mechanical Engineer, the cylinder wall thickness is clearly too thin for design safety margins.

I just had and I think debunked my own argument for why it is wrong but still safe. The crux of the argument being...does the 7 shot have 6 or 7 flutes. Without that insight...common knowledge I don't posses I'm sure...I should shut my trap before I make uninformed pronouncements.

If the 7 shot only has 6 flutes then you would have a thin walled offset. For the sake of argument...if 6 holes are drilled in a cylinder designed for a 7 chamber offset then you should be fine. I'm not for a moment saying its right or that I would shoot it. I'm kinda an obstinate stickler for actual physics vs. rule of thumb and this probabaly isn't the place to engage in that "how many angels" argument.

So before I get too flamed...let me seperate my stance.

1. This is wrong and I would never knowingly shoot it. It would be sent back to S&W IMMEDIATELY.
2. The propeller hat, paste eating, egghead in me wants to know and debate the actual, mathematical physics of the problem as it relates to what was actually physically constructed..ie. while clearly wrong, is it unsafe for the illustrated cylinder.

I too love S&W revolvers, but that is a disgrace for a company of that caliber to turn something out like that. I'm sure they will make it right, the title says it all though...come on!

olafpfj wrote:2. The propeller hat, paste eating, egghead in me wants to know and debate the actual, mathematical physics of the problem as it relates to what was actually physically constructed..ie. while clearly wrong, is it unsafe for the illustrated cylinder.

The geometry on a fluted cylinder is set up so each chamber is centered under the non-fluted portion of the cylinder with the actual flute being in between each chamber. Look at the six-shot example below. See how the wall thickness is consistent between each chamber as well as from the chamber to the outside of the cylinder wall.



The design engineers clearly decide what the minimum wall thickness needs to be for a specific designed chamber pressure for a specific grade of steel. Change the kind of steel or change the kind of chamber pressure and the thickness required will change.

The problem in the original picture (copy posted below) is putting 6 chambers under a 7 flute cylinder means the chambers are no longer centered between each flute. Look at the steel thickness between the chamber and the cylinder wall at 4 o'clock (Exhibit "A"). It is obvious that the design engineers were comfortable with that metal thickness having the necessary strength (including safety margin) for the .357 mag cartridge for that diameter chamber within that diameter cylinder.



Now look where the chamber is not centered under the flutes at Exhibits "B" and "C". The metal wall thickness is obviously much thinner than the design thickness, roughly half the thickness of exhibit "A". Half the thickness can even be less than half the strength, but you'd have to run it through stress analysis software to know the real values.

Anyway, back to the original point: it is clearly dangerous because the metal thickness is substantially less than the designed thickness.

Greetings,

The revolver under discussion is mine. As has been said, I took it out to test fire it and get it sighted in (no problems) and just finished an action job when I noticed something odd. I was double-checking the timing when I saw that the flutes seemed to be changing position in relation to the timing notches. Looking at the front of the cylinder ...... Well, you can see for yourselves.

The cylinder wall thickness of the correct chamber is 0.10". The thinnist one is 0.04". Methinks a loss of 60% of a chamber wall might just be a bad thing.

To tell you the truth, when I first noticed the screw-up, I laughed. I thought it was funny. I don’t think it’s funny anymore. The more I think about it, the madder I get. I doubt I’ll be in a better mood when someone from S&W contacts me after the first of the year.

If I had fired some full-bore factory .357 loads instead of the fairly mild .38 Spl loads I used, I might very well have been injured. By now, lawyers would be involved.

S&W is closed till 1/2/12. I emailed them last week, but I guess they haven't gotten around to their in-box.

The final QC was signed off by "Brian C" on 12/2/2011. That was a Friday. I'm thinking this gun was good old Brian's last inspection of the week. Maybe he was more concerned about the hot date he had planned than he was about how many flutes there should be in an SSR cylinder!

That is truly a shame, but great they actually let you know who inspected it or that is was inspected at all. I'm sure they will get you taken care of. But really embarrassing on their part. Especially for a Performance Center product that are supposed to be top quality.

Another pic or three ....

Japle

You take very nice pics. I hope you come back and post "after repair" pics as well.

You said something about an action job. Did you diy or have a smith do it? Just wondering if a third party missed the improperly fluted cylinder as well. It could easily happen to an excited buyer (of a thousand dollar "high quality" gun), but one would think a professional smith would have noticed.

surv

You said something about an action job. Did you diy or have a smith do it?

I did the action work myself. Been doing them for decades. That's how I caught this "feature". I was doing a final check on the timing and noticed that, as the cylinder rotated, the flutes were changing position in relation to the timing notches.

glad you caught it when you did. I don't know that most of us would have noticed the glitch before loading up the magnums. The folks at S&W will certainly make it right, and hopefully go another step to make sure you'll be a happy camper.

Jumping Frog wrote:

olafpfj wrote:I may be well out of my depth on this comment but here goes...

While it is CLEARLY not correct I don't think that it is dangerous. I would like to hope that the safety tolerances are such that, while not correct, is still OK.

No, it is dangerous. Speaking as a Mechanical Engineer, the cylinder wall thickness is clearly too thin for design safety margins.

Agreed, design margins in Mech E projects are much tighter than the factors of safety in buildings and bridges.

Japle wrote:The final QC was signed off by "Brian C" on 12/2/2011. That was a Friday. I'm thinking this gun was good old Brian's last inspection of the week. Maybe he was more concerned about the hot date he had planned than he was about how many flutes there should be in an SSR cylinder!

Manufacturing and assembly errors are often blamed on the QC department, because "they didn't catch it." 100% inspection does not result in defect free product.

In reality, most errors result from a variety of causes. This cylinder never should have made it past the machining operation. It should have been immediately identified as scrap and marked with red paint or some similar method. Then they should have investigated the root cause for the defective part and corrected their process.

UPDATE 1/3/2012

This morning, I talked to Jon Young at S&W Customer Service. He’s talked to the other CS and production guys and no one has seen a gun like this that made it out of the plant. They’ve seen cylinders like this in the scrap bins, but not on guns that were shipped.

He says there’s no problem if I keep the cylinder. Also no problem with anyone messing with the action. I just have to include a note stating the problem (I’ll include a few photos) and ask that they just replace the cylinder.

He says I can ask for a non-fluted cylinder, but he can’t guarantee I’ll get one. There might be an extra charge. I pointed out that it wouldn’t be any more expensive to install a non-fluted cylinder on purpose than to install a 7-fluted cylinder by mistake. The non-fluted cylinders come from the Performance Center, though, so he doesn’t know how that’ll work.

S&W is very aware of the fact that my gun is the subject of threads on at least 12 different firearms forums. They know I’m going to report on what happens.

Jon said he’ll have a shipping label emailed to me. I’ll remove the cylinder and sent the gun in.

Wish me luck!

Sounds like they'll make it right...and you'll get to keep a conversation-piece paperweight.

Please keep us informed about how it all plays out.

Update – 20 January:

Well, as of today, S&W has had my gun for two weeks. Considering the fact that it’s the subject of distinctly unflattering threads on 15 different firearms forums and S&W’s Facebook page, I thought I might get a little quicker action.

Guess not. I haven’t heard a word.

Japle wrote:Update – 20 January:

Well, as of today, S&W has had my gun for two weeks. Considering the fact that it’s the subject of distinctly unflattering threads on 15 different firearms forums and S&W’s Facebook page, I thought I might get a little quicker action.

Guess not. I haven’t heard a word.

Maybe if the S&W employees didn't spend so much time at work surfing the web, you would have your gun back.