so ive decided to de-screw my build and rivet it. got my bolt cutters ready to modify, already replaced the rear trunnion screws (it aint pretty, but she'll hold) and now im ready to pull the barrel. as the topic says i dont have a press, so what's a good way to push out the barrel pin?
i think i remember a thread about this from an earlier date, so if anyone's got a link id appreciate it. but off the top of my head, i was thinking about trying a gear puller, same way im going to pull the barrel. think itll work?
ok, here is the deal... BIG hammer.... it's all about kinetic energy, momentum, and overcoming the coefficient of friction.
if you are trying to get it started with a punch, forget it.
I lay the trunion flat on something... like a big flat anvil, take a 1/2" diameter steel rod (like from a socket breaker bar) set it on there and wack!
the big rod lets you hit it with authority!
this will get ANY pin moving, in my experience. Even romy pins.. although with a romy pin, I sometimes need to work them back and forth (flip hit flip hit) untill it's loosed up a bit.
I have a second 1/2" diameter rod that I ground on, so there is a very short "punch" oming out of it at one edge, this rod sits in the trunion "L" where the pin is, and it nice and steady, and it can't wander.
this lets you wack with some power.
only after the pin is driven into the trunion a little do I get the "proper sized" punch
I built up a jig with a welder and some angle iron from an old bed frame. basicaly just made a U channel. I set the barrel/trunion in it, and set one end on the concrat, and use my big 1/2" rod and some nickels to drive out the barrel.
most AK building tools are easy enough to make with limited tools and a little scrap metal.
I have sacrificed several wrenchs and socet set drivers, etc/
Before you do anything, I would offer 3 simple words; Soak that Pin.
I have done several Romy pins and with a few days of soaking everyone of them came out EASY!
Also, when I press my pins I made a jig from a set of "Drill Bit Stops".
A small one that holds a hardened punch,
(same diameter Stop as the punch with several lengths of punch, very short for the start, long for the push) and another Stop with a diameter somewhat larger than the Barrel Pin for Trunion support.
I make a relief grind in the Support Stop that mates to the surfaces of the face of the trunion so that the trunion can sit flat. You can hold the support stop in place during the press with a bit of Tape.
Before I bought my 20 ton ress, I did all my Pin R&R with a large Vise and a Hammer, putting pressure on the pin with the vise and then a smack with a hammer to the face of the vise got them moving. Fairly easy.
The Press just makes it that much easier.
Delmarksman, When you state "face of the vise" you are talking about the Moving part of the casting?
Do you strike it in-line with the srew thread? Would a dead blow hammer work, or just use a steel BFH?
As much as I hate to "abuse" tools, this whack and shock technique seems to have a lot of fans.
I want to keep it in my bag of tricks in case it is needed, and would like to be sure of the technique. Thanks.
Yes that's correct.
I will say that I broke my first vise with this method, BUT it was a really dinky chinky made unit. I bought a 6" Kobalt (brand name) from Lowes for +- $40 and it's built like a Tank. Smacking it with a 4# hammer has barely smooshed the paint. Comes with an Unconditional Lifetime Guarantee.
It seems that pre-loading the pin and the the jarring helps to break the seal.
But I will say again,
Soak your pin and barrel at the trunion with a bit of penetrant.
After doing several that way, someone brought me their Polish (which are generally not known to be a bear) to remove their barrel pin on my 20 ton press. I had advised him to soak his for a few days and he did not.
I can say for a fact that his pin was easily 50-100% harder to remove than the soaked ones.
I then turned around and did 3 Romy's and all came out with little effort.
I will always soak 'em from now on.
Here are a couple pics of my pin and barell removal tools;
I tried it with my vise and with my 12-ton press, and I couldn't get it to budge.
Someone on another board recommended an air hammer. I put that thing in the vise and layed on it with the air hammer and it practically flew out of there!
You just gotta really lay on it before you pull the trigger, and work in very short bursts until you get inside the trunnion. If you don't, the punch will walk around and screw up your sight block, barrel, etc.
That's a very nice setup you got there, Delmarksman. I'll have to do something similar if I build more of these things.
Thanks for posting the pics.
Sure, no problem, pics always help...thousand words and all that...
I think that with the vise method, as you said about the Air hammer, the key is to have as much pressure as you can get on the pin before you hit it. A Pre-load so to speak.
Also, as said before, I tape the punch to the (moving) jaw and the stop to the trunion so there's less to try and hold while cranking down the vise jaws.
1 hand operates the vise, the other holds the barrel/trunion with the stop taped to the back side.
Not shown in the pictures is a set of large washers, set to the same height as the stop, on the same side, for extra support of the trunion. Helps the trunion stay square to the press.
Barrel puller is Auto Zones Power steering Pulley Puller PN# 25190.
Don't bother going to the website, you will not find it there, but it is on the shelf.
With a small amount of relief grinding to fit around the trunion corners, it works like a charm.
Mine have all come out using a 3/8 or 1/2 in. drive hand ratchet.
I do like to put the jaws in a vise to prevent them from popping off though, and that makes it easier as you don't have to try and hold the barrel and work the ratchet at the same time.
thanks for all the help guys, ill go soak it in some more CLP for the rest of the day. thatll make two days with it doused in CLP and then take the biggest hammer i can find to it.
ill even post pics once its out
PB blast works better than anything, nothing can stand in the way of PB blast!
hmm, well then i'll have to give that a try. thanks!
The stuff is magic.
Until recently, I pressed all of my barrel pins with an 8" bench vice.
Now I have a 20T press
PB Blast is an excellant penetrant, so is 3 in 1 but Kroil will also work really well.
It's the "Oil that Kreeps", ya know.
Many Moons ago when I worked on Jet Engines for a living we used Breakfree CLP on the bolts in the "Hot Section", soaking them prior to removal. I was usually left wanting for more/better.
This was with the true Mil-Spec stuff that came by the Gallon, not the comercial stuff that is sold today
in the spray cans.
I think that you would be better served letting it soak with one of the others for a few days.
If you have trouble with getting the pin to move, be advised that hammering on it may mushroom the head of the pin and "Work Harden" the end making it more difficult to drill out if it comes to that.
So have patience and don't be in too big of a rush, let 'er soak for a few days, atleast.
The air hammer method is by far the easiest way to get the job done. I chucked up the pointed bit in the drill press and turned it down to make a punch. PB blast the parts the night before and it took all of about 10 seconds to knock out that barrel pin. This is my firs build and I have learned tons from all the posts. Totally disassembled the entire rifle in about 2 hours. Not including going to Lowes to buy the 6 inch Kobalt vice.
I used the air hammer to start to move the barrel pin. Moved it a bit, then wacked it out with a BFH and a punch. Took longer to write this than to do it.
I used a 6 inch gear puller to pull the trunion from the barrel. used a stack of pennies against the barrel, and it crushed the bottom 2 pennies. The trunion poped and groaned, but it pulled it right off the barrel.
This is my very first build. Taking an ak apart isn't hard....if I can do it, anyone can. I intend to build my yugo underfolder with drive screws. I will get some pics and post the results.
One of the things I was guilty of when I started was thinking that this rifle is some delicate instrument. it ain't at all, it is a battle rifle. It will come apart if you follow the instructions on this and any number of other websites...
Try a 6 inch vise, a 3/8 socket ground to fit the trunion side, a really short 1/4 in. push pin, plus sucessively longer ones, and a piece of pipe on the vise handle. Torque it down until the pin ALMOST buckles. Then whack the movable end of the vise with a big hammer or hand sledge. It'll probably move a touch. Use longer pins as needed. My worst case was a Tantal that needed a pin, made from a piece of a 1/4 in. drill shank, so short I only got in 2 vise cranks before putting in a slightly longer one. The push pin got squashed, now looks like a little barrel.
Of my 3 Romys, one came out by hammer and punch easily, one in the vise with difficulty, one almost as bad as the horrible Tantal. Only one gave an audible pop, and all the tough ones fought me all the way.
Pushing the barrel was similar, one with a hammer and socket, the others pretty tough using the Autozone pulley puller in a vise and a big long wrench to turn it. Just be sure to shim the barrel breech so you get a straight push.
BTW, I heated them, soaked for a week in PB Blaster, froze, used receiver heating, air hammered - didn't help until I got the monster 6 inch industrial vise, made short push pins and cranked and whacked.
Also, push from right (looking forward, to left. My pins were tapered a bit less than .001, assuming it didn't happen from all the hammering!