Gas cylinder polisher

[ipscgraz]

I was trying to find a way of buffing up the inside of my M14 Gas cylinder.

I figured a rotary tool would work but I couldn't find anything that would fit easily.

I held a .270 case in the chuck of a 3/8 drill & held the chuck still while I slowly rotated the drill. Sure enough the jaws of the drill collapsed the mouth of the nice soft brass case.

Some masking tape to build up the diameter and a long skinny strip of emery and away I went. The emery gets dull fast but if you tear off the last inch you get a fresh working surface of the emery.

After about 15 minutes the gas cylinder slid down just like it was supposed to.

A little cold blue in the morning and it's gotta be good.

 

[Winz]

Huh?

I'm not following exactly what you are doing. When your gas assembly is together, your piston should actually have some stiction

 

[olegs69]

He may be onto something.
I am interested to see how this turns out.

My gas system is a bit rusted up.
There's another thread about that somewhere.

 

[DaveGP]

Just use a cleaning rod tip with the slot in it - strip of emory cloth and a drill works too.

 

[powmia56]

We were welding gas cylinders at the clinic on Sunday. It is possible, due to the heat of welding, to get a very small deformation which can cause some sticking. If I remember, Graz' cylinder was the only one that seemed to be having some problems and he was going to take it home and do a little fine work on it.

Winz: You don't actually want sticking. The friction of the cylinder combined with the vacuum created as the cylinder slides down should slow the travel but this is not the same as sticking.

DaveGP: I would not ever recommend polishing the inside with a drill. It moves too fast and could easily remove too much material.

 

[45ACPKING]

I'll be trying to get some time in the future to inspect ipscgraz's gas assembly to be sure the solution was indeed that simple. It was a nerve wracking moment at the clinic when this issue rose it's ugly head. We had well over a dozen gas assemblies welded up and we all had some filing and fitting to do, the blueing past came out for some touch ups here and there. While i do not recommend the above method for cleaning the gas cylinder, I believe in this case it was probably the best solution.

there are specific drill bits availlable for the purpose of cleaning carbon build up from the gas ports and gas cylinder walls..... BUT to the best of my knowledge these are only availlable for gas cylinders and gas ports that are to USGI spec.

 

[DaveGP]

DaveGP: I would not ever recommend polishing the inside with a drill. It moves too fast and could easily remove too much material.

Perhaps you should read the USAMU 'Accurized National Match M-14 Rifle'
Pg 4.2.9 reads 'the inside of the gas cylinder is now polished with wet or dry abasive paper mounted on a mandrel ; first with 320 grit then finally with 400 grit'
Only an idiot would wail away with 80 grit for 20 minutes....

 

[Dimitri]

BUT to the best of my knowledge these are only availlable for gas cylinders and gas ports that are to USGI spec.

Even those are just standard drill bits with a handle selling for many times "new" price, measure/test different drill bits till they work in your Norinco?

Dimitri

 

[Winz]

Winz: You don't actually want sticking. The friction of the cylinder combined with the vacuum created as the cylinder slides down should slow the travel but this is not the same as sticking.

Yep, you are right. I couldn't come up with the right words at the time. Vacuum would be the proper word for it.

 

[ipscgraz]

I'll be trying to get some time in the future to inspect ipscgraz's gas assembly to be sure the solution was indeed that simple. It was a nerve wracking moment at the clinic when this issue rose it's ugly head. We had well over a dozen gas assemblies welded up and we all had some filing and fitting to do, the blueing past came out for some touch ups here and there. While i do not recommend the above method for cleaning the gas cylinder, I believe in this case it was probably the best solution.

there are specific drill bits availlable for the purpose of cleaning carbon build up from the gas ports and gas cylinder walls..... BUT to the best of my knowledge these are only availlable for gas cylinders and gas ports that are to USGI spec.

Yup; i wouldn't mind you seeing this. I think it worked out well but what the h#ll do I know...besides which I think i left a recoil pad at your place just to prove I'm a dumb#ss.

Nerve wracking? Well, maybe. I'm kind of a nerve wracking guy. However 140 years from now that won't matter.

 

[WWIII]

All you need to do is get a piece of wooden dowel (slightly smaller than the ID of the cylinder) then cut a slot in the middle of the dowel at one end with a thin blade such as a hack saw, then take a strip of emery cloth and slot it into the dowel slot you just cut, then wrap the remaining emery cloth around the dowel and put the opposite end of the dowel in a drill chuck then you can ream the cylinder out with an in & out motion. This will polish your cylinder up and remove any burrs & nicks inside. Use 300-400+ grit emery or aluminum oxide paper and reblue the inside of the cylinder when finished.