Whats a good way to estimate barrel cylinder gap?

[Blondie.357]

If you don't have the little thingymajig that gun smiths use to do it is there another way? I refuse to believe that one has to send their gun in the mail for weeks on end just to have some schmuck take a little tool to the gap and figure out what it is.

I know a credit card is .0200 inches thick, and I had some thick paper that when folded in half was just slightly less thick than the credit card, so I estimated that that paper was about .009 inch thick.

It didn't fit through the gap, but a piece of normal printing paper does.

Anyone happen to know the thickness of regular household printing paper?

And perhaps there is another more precise method than what I am trying to do?

 

[hickstick_10]

A feeler gauge.........those things that you use for checking sparkplug gaps. The have all those little metal strips with the different thicknesses marked on them, and fold up like a pocket knife.

Cost about 5 bucks or less

Just as precise as a gunsmith. Alot of them use just that.

There available at any hardware store, about as common as a claw hammer.

 

[Blondie.357]

Thanks,
Now I have to a reason to go to Lowes. "I love that store"

 

[johnbt]

Dollar bills are .0043".

"It is a piece of paper measuring 2 5/8" by 6 1/8" with a thickness of .0043". The composition of the paper and ink is a state secret. New notes will stack 233 to an inch, if not compressed, and 490 notes weigh a lb. Every thousand notes cost the Government $8.02 to print. At the same time, over 2 billion bills are in circulation, each with an average life span of 18 months."

 

[Magnum Mike]

Thanks John. Now I can say I learned something new today!

 

[gyvel]

A feeler gauge.........those things that you use for checking sparkplug gaps.

Also available at your local auto parts store or any Sears where they sell tools.

 

[Elvishead]

Also available at your local auto parts store or any Sears where they sell tools.

Yeah., but they don't saaport loco nashcar.

 

[balin]

note book paper is .003 , we often use it as a quick feeler gauge in machine shops.

 

[Blondie.357]

Well I bought the gauge, its just what I was looking for but I have another issue if someone can help me.

What is the proper way to measure the gap? I ask because there seems to be 2 ways to measure it.

I can measure it by pulling the cylinder back and forcing the gap to widen, or I can measure it the way it sits at rest.

Without forcing the cylinder back the gap is .003

If I hold the cylinder to the back its .007

Which one is the correct measurement?

 

[Don P]

Per my book, The S&W Revolver, a shop manual by Jerry Kuhnausen it is the .007 reading you obtained and all is O- KE- DOKE- E

 

[sheepman]

You also measured a 4 thousands of end shake (.007 - .003)

 

[hickstick_10]

congradulations

you are now qualified to measure cylinder gaps on revolvers

I would expected 5 though or less from a smith and wesson

 

[Blondie.357]

I would expected 5 though or less from a smith and wesson

I have put quite a bit of magnums through this gun.

I doubt it was .007 when it was new.

 

[KyJim]

You also want to measure cylinder gap while the revolver is in full lockup. Check out Jim March's revolver checkout sticky at the top of this forum. I believe SW now considers a revolver to be in spec at .007 or even higher, though I could be wrong about this.

 

[Dfariswheel]

Sorry, but no you don't.

Even if a revolver cylinder is pushed forward when the hammer is cocked, this is an artificial state that means nothing.
If the cylinder is moved forward when cocked, the backlash in the action allows the cylinder to be shoved right back by recoil.

The object of gaging the cylinder gap and cylinder end shake is to get a true measurement of what state the action is in.
Even if the cylinder were to be pushed forward, all that is is the spring pressure of the hand. When the gun is fired, recoil pushes the cylinder backward against the slight spring pressure, so that spring pressure pushing the cylinder forward is not a true measurement.

Most revolver measurements are taken with the action at rest.
One of the few cases where the action is cocked is in the older Colt revolvers where the action lock-up is judged with the trigger held to the rear.

 

[KyJim]

Sorry, but no you don't.

Thank you for the correction. Your opinion is one which I consider to be right up there with "holy writ." It looks like there needs to be a re-write done on the sticky thread.

 

[jad0110]

I believe SW now considers a revolver to be in spec at .007 or even higher, though I could be wrong about this.

Actually, S&W now considers all the way up to .01" in spec :barf: .

I guess I was lucky that my 642 measured .012"; they ended replacing the barrel under warranty.

 

[Lost Sheep]

With or without a cartridge in place?

I believe I would measure B/C gap with a cartridge in the chamber in firing position (don't use a live one, you are only interested in how the rim thickness affects the position of the cylinder, so empty is just fine, and infinitely safer).

Lost Sheep

 

[Blondie.357]

I believe I would measure B/C gap with a cartridge in the chamber in firing position (don't use a live one, you are only interested in how the rim thickness affects the position of the cylinder, so empty is just fine, and infinitely safer).

I did that, there is no difference.

 

[Blondie.357]

Oh good you can easily fix end shake without sending your gun in to be tuned.

http://www.midwayusa.com/viewProduct/?productNumber=392482

Can you stack these washers up? They are .002 inch thick, so if I wanted to make my gun have close to a .002 gap I would have to use 2 of them. Is that ok? Or are you only supposed to install 1?