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-   -   Gas block pins (http://www.firearmstalk.com/forums/f20/gas-block-pins-30009/)

Fisherking 08-03-2010 04:39 PM

Gas block pins
 
I'm telling you I don't know what kind of steel and at what pressure the gas block pins are put in at but over the weakend I took the pins out of my Norinco M4 carbine. WHAT A PIA . The pin was stuck so I centerpunched it so that the tappered pinpunch would not walk. A couple of good hits and I shatered the pin punch which left a piece of it in my finger, I gave up on that idea and decided to drill it out on mydrill press. The first one drilled fine the steel was hard at first but once the cobalt drill caught it walked right through it. The second pin was not so easy.I started it by center punching it again and using a small drill started drilling. The drill would not catch and I started to bore a hole a little at a time. I thought I was deep enough to start the bigger drill and when I did it started good so I added presure and it walked:eek:. I was starting to get mad at this point but I kept it in check. I turned the block and gun over and started on the other side same thing started than walked:mad:. Now by this time I was totaly PO ed so I took a bigger drill and drilled the F**k out of it:D. To say the least I got the Gas block off but I thought it was totaled,but not so it was made out of steel. I welded and built up the block where it was mangeled redrilled aand it was good to go and workes flawlessly.
I can hardly waight till my free float hand gard and new gas block with the flipup sights come in so all that pain and agravation I went through is worth it.
Any one else have a story like this one please feal free to share. You know what they say misery loves company.

F.K.

Jpyle 08-03-2010 04:49 PM

Quote:

Originally Posted by Fisherking (Post 325270)
I'm telling you I don't know what kind of steel and at what pressure the gas block pins are put in at but over the weakend I took the pins out of my Norinco M4 carbine. WHAT A PIA . The pin was stuck so I centerpunched it so that the tappered pinpunch would not walk. A couple of good hits and I shatered the pin punch which left a piece of it in my finger, I gave up on that idea and decided to drill it out on mydrill press. The first one drilled fine the steel was hard at first but once the cobalt drill caught it walked right through it. The second pin was not so easy.I started it by center punching it again and using a small drill started drilling. The drill would not catch and I started to bore a hole a little at a time. I thought I was deep enough to start the bigger drill and when I did it started good so I added presure and it walked:eek:. I was starting to get mad at this point but I kept it in check. I turned the block and gun over and started on the other side same thing started than walked:mad:. Now by this time I was totaly PO ed so I took a bigger drill and drilled the F**k out of it:D. To say the least I got the Gas block off but I thought it was totaled,but not so it was made out of steel. I welded and built up the block where it was mangeled redrilled aand it was good to go and workes flawlessly.
I can hardly waight till my free float hand gard and new gas block with the flipup sights come in so all that pain and agravation I went through is worth it.
Any one else have a story like this one please feal free to share. You know what they say misery loves company.

F.K.

Not to be a smart ass but you do know that the pins are tapered and only come out from one side. Flipping the upper doesn't work. Did read here recently that someone had to press the pins out and that it required like 50 tons of force to get them out, believe it was a Del-ton upper.

Fisherking 08-03-2010 08:52 PM

Ya I knew about the pins but thanks for the heads up. The one side almost has a cap on them.
You don't happen to know what brand of upper that the guy had to use the 50 ton press on.
To hold the old Gas Block on I just used roll pins. I was looking in Brownells but I didn't see any taper pins. If I decide to use the old G.B. I will use a tap and thread it.
F.K.

Highpower 08-03-2010 11:21 PM

I use a cup-tipped punch for the taper pins with the (rounded cap) convex ends. I have only had trouble 1 time while removing a pin on a Colt H-BAR Sporter. Barrel/FSB was securely held in a bench vice with soft jaws for solid support. The front pin came out with a few solid hits, but the rear pin refused to budge. I finally ended up flatting/facing the end of the pin (mill) and pushing it out in a 20 ton shop press.

That was nothing compared to getting the front sight band off of my Model 1917 Enfield however. When it finally broke loose, I had a 4 foot "extension" on the press handle and it sounded like a .44 Magnum going off! :eek:

TheDaggle 08-05-2010 12:23 AM

Quote:

Originally Posted by Jpyle (Post 325275)
Not to be a smart ass but you do know that the pins are tapered and only come out from one side. Flipping the upper doesn't work. Did read here recently that someone had to press the pins out and that it required like 50 tons of force to get them out, believe it was a Del-ton upper.

This was my unfortunate tale. Had a machinist who bent a punch, milled a block to hold the post, milled a new, stronger punch, then finally put it in a 50 ton press with a hardened steel t block across the pins :eek:
My upper was assembled by DTI, and I believe Troy said his DTI upper came without any pins at all, so in the future I think set screws may be the way to go...


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