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installing spindle valve assy. in new gas cyl

1964 Views 4 Replies 3 Participants Last post by  Tommo
I have a new USGI gas cyl from M&A Parts, and a spindle valve assembly from Fulton. It won't go into the gas cyl. Is there some trick to this? is it a part that requires fitting?

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The installation of the spindle should be a simple push in with thumb, or LIGHT taps, with a brass hammer (light taps??,,tap the end of your thumb with the brass hammer, if it hurts, you have gone pass the light tap stage). A smug fit is desirable. Try a little lube and taps with the brass hammer, (no banging away with the ball peen), if it goes in, work it back and forth and around a bit. Hopefully this should loosen the spindle/gas cylinder fit up, then remove the spindle and remove that lube and then reinstall. If the spindle will still not go in without the lube, add the smallest amount that will work. Remember the rule,, no oil/lube in a gas system.
Now if the above is of no help and the spindle will not go in,, you are going to need to make some measurements. You will need a micrometer and it would be nice to have a ball gage. IF in fact your gas cylinder is GI,, you could assume that that the spindle valve passage is within tolerances,,0.2301” to 0.2306”, (be careful, this word “assume” can get you into a lot of trouble).. Using the mike, measure the dia. of the spindle valve shaft, it should be between 0.2294” and 0.2300.”..Now if it is too large you have some choices,, send the spindle back and tell them you need a spindle that meets GI specifications. You could order as many spindles as you can afford and hope one fits.. You could send the gas cylinder to someone who supplies the spindle and ask them to find one that fits,, Or you could hold the spindle, by the head, in a drill press and with abrasive paper/cloth of 220 to 300 grit, CARFULLY (using the mike a lot), reduce the spindle shaft dia. until it is a tight push fit in the gas cylinder. A better job could be done on a lathe, just remember to use a center on the shaft end, (a small carbide center drill will be needed)..If any one ask,, you can tell them that little center drill hole in the spindle is the latest NM modification.
Now the BEST way,, would be to use the ball gage and mike to determined the inside dia. of the spindle valve hole. Take that measurement, subtract 0.0002”,, contact a supplier and tell them you need a spindle valve with that shaft dia. You could have as much as 0.0012” clearance, however if you are going to all this trouble I would not have more than 0.0005” clearance…
Two more things, first: make no alterations to the gas cylinder, if you screw up, that is a lot of money, second: GET KUHNHAUSEN’S BOOK.
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Fulton seems to be selling allot of non-USGI parts these days!
yes, Tommo, I'm figuring that out. orders today went out to USArmory and Claude at RA Parts. I hope to have my problem fixed. Upon discussion with Claude about new GI gas cyls, he mentioned the surface facing the gas cyl lock should be in the white, and mine is finished. I wonder, refinned? Arg.......
You might also try Numrich Gunparts www.e-gunparts.com, most of their parts seem to be USGI. Just do not order elevation spindles or flash suppressors, both are castings!

Parts I have ordered that are USGI:

bolt (NA)
bolt lock
firing pin
oprod (NA)
oprod spring guide
sight base
sight base spring cover
stripper clip guide
trigger unit
windage dial
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