Flutes Off Center Of Chambers

[Tar Heel]

A careful observer will notice in the provided photo, that the carbonization patterns appear not to be directly centered over the chamber holes. You can detect a slight offset to the circular pattern between the flutes. This revolver is timed correctly and is very tight and in fact the blast pattern is centered over the chamber hole. Chamber holes align perfectly with the bore on each hole. Why do you think the chambers are not precisely centered between the flutes? Or is it, the flutes are not centered between the chambers? Guesses?

127657

[rbertalotto]

I'd like to see measurements of the chamber walls with regard to the flutes. It looks like the chamber at 1 o-clock in your photo has more "meat" to the left than it does to the right. They all appear to be slightly rotated a few degrees to the right.

Somewhere on the internet someone posted a picture of a S&W revolver with the flutes cut so far off that a few chambers had paper thin walls. Not sure how that gun ever made it out of the factory!

[contender1]

What make of gun is that?

[Stonecrusher]

I have a 625JM like that. I never noticed until after I fired it. On mine the cylinder walls are still thicker at the smallest side of the fluting than from the charge hole to outside of cylinder. The gun is close to perfect in every other respect, so I choose to ignore it.

It looks like yours is the same way, with more meat in the fluted areas than the outside of the cylinder. It shouldn't happen, but someone was half asleep when they performed the fluting operation and someone else when it went through QA. If you sent it back, I am sure they would replace it.

Things slip through QA all the time. It is a shame when we spend our money, and a lot of it, to not get a perfect product.

[Tar Heel]

To above...it's a S&W MOD57. I bought it in '85. I never really noticed that until today when I decided to remove the carbon from the cylinder face. The gun is tight in all respects but there is a difference on either side of the flute. I will take a few more shots and then go measure it. I'm not sending it back. It's been 30 years in service and it's no harm. I was just curious. Let me go measure the rascal.

[Tar Heel]

Here ya go. Yellow arrow shows chamber mouth equidistant from the bottom of the forcing cone. Red arrows show flute edge off center of forcing cone. I have the shed all shut down and secure so I will postpone the measuring for tonight. You would think they have a fluting jig and the fluting is done referencing the chamber hole(s). There must have been a lot of slop in the fluting jig that day. It's surely cosmetic but still. Mechanics is mechanics or else they do (did) that by hand?

Granted it's not much but that one section of the chamber wall is about 2 or 3 thou thinner there than the other side. It's a 41 so there is a tad more wall to begin with.

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[Tar Heel]

You know....it could be that the chambers are all off by a degree or two due to the location of the bolt stop detent. I will have to measure the chamber walls as best I can. Sure wish I had a machine shop. I'll have to use cave man tools.

[Nueces]

Another thing to consider is that the rear face of the barrel may not be perfectly square. If it isn't, then the carbon rings might be offset some.

[Tar Heel]

It's probably a combination of all the factors. Axial wiggle, rotational wiggle, surface facing, crane wiggle, and I'm sure some magic stuff too. Doesn't seem to affect anything and I was just curious. All my other DA & SA revolvers are blued so I don't get to see this except on this one revolver.

[JSnover]

There are tolerances for just about everything. Yours is probably within spec if you only found a difference of "2 or 3 thou..."

[Zouave 58]

Guess the real question is how the axis of the chambers aline with the axis of the bore. If they do aline then perhaps the mismatch is more annoying than mechanically significant. Is there any evidence of lead shaving to one or the other side of the barrel shank? And , indeed, the rear face of the barrel may not be square to the cylinder face as it was common to set the barrel/cylinder gap by hand filing during assembly.

[Forrest r]

I've seen this before when I was testing the cylinder gaps on a dw looking for the best accuracy. The dw didn't do it when there was 1/1000th's to 2/1000th's cylinder gap. But it really started showing up by the 7/1000th's to 8/1000th's cylinder gap mark.

I'm not saying that's what going on but it is possibly another piece of the puzzle to look at.

[Tar Heel]

Is there any evidence of lead shaving to one or the other side of the barrel shank?

No evidence of any of that. This gun is a shooter and one of my most accurate 41's. Barrel/cylinder gap is negligible. You are hard pressed to see any gap through there. I will try and find my feeler gauges to measure it but she is a real shooter.

[MtGun44]

Flutes are just for lightening and 'styling' and have no real effect on anything, so appear
to not be particularly well aligned to the chambers. Seems like a pretty big "and so?"
as far as function, but does indicate a touch of sloppy alignment in the machining
process, but without impact on accy or function.

My suggestion - slap your hand and give yourself a good talking to for looking that closely
at a good shooting revolver! :kidding: :bigsmyl2:

Bill

[Tar Heel]

My suggestion - slap your hand and give yourself a good talking to for looking that closely at a good shooting revolver!Bill

Precisely! The engineering got me to thinking about datum. What is the root datum on a revolver action and then the build from there. Cool geek stuff.