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jumbopanda
11-29-2006, 10:52 PM
Ok, the S just HTF for me.

My tap broke off inside my AK trunion! :mad: Now before you laugh and tell me that I should have done a rivet build and whatnot, tell me something. Should I go get a special tap extractor or just let it be and go with two screws? The hole that the tap is stuck in is the middle hole, btw.

Sydwaiz
11-29-2006, 11:04 PM
Where are you located? You can try finding a friendly machine shop with EDM machines. The easiest way would be with a carbide endmill. That's how I remove broken taps. I use my EDM as a last resort.

jumbopanda
11-29-2006, 11:26 PM
End mills? Do you just feed them straight down into the hole? Isn't it hard to cut through taps?

bu-bye
11-29-2006, 11:46 PM
http://www.cartoonstock.com/lowres/mly0582l.jpg

A good end mill will cut through just about anything. The other thing you can do is weld it all up then re-drill it.

NeoWeird
11-29-2006, 11:51 PM
If you are careful, and if it's not too deep, you can try to chip it out with a good ***** punch. I had to do that, but I had only a TINY bit in, anything more than a 1/4" or so and I would not recommend it. Drilling is NOT an option. If you want to keep it cheap, you can always knock it out, redrill to a larger size, and retap. Carbide MIGHT work, but I've never tried using an endmill to get broken taps out (not saying it won't work, or that you shouldn't, I've just never done it). I'm by no means an expert either, so keep that in mind.

Have you tried to back it out a pair of needle nose pliers, two nails, etc? The taps used on AK builds are pretty thin and once they are under pressure if you put much lateral force on them they can sheer off right at the top of the AK metal, but they are not bogged down and jammed in tight. If you don't 'cut' it out, I'd try chipping it a tiny bit (be careful not to deform the metal it's in) and then back it out with something. I've even heard of takine a piece of wire and winding it up, then turning it and feeding it into the thread grooves, then when you get it in as deep as it goes you can pull on the wire fairly tight and it will grip the tap walls and help back it out.

If you do this, you might be able to use the existing cut threads and just get a new tap to finish (although expect a sloopy thread job, and you will probably have to go a size larger to get positive thread lock).

Good luck with that.

ETA: Keep in mind that taps are hardened steel, so you better use a good carbide endmill if you do go that way.

jumbopanda
11-30-2006, 12:38 AM
Tried twisting it out, inserting nails into the flutes, and breaking it. None worked. I think I'll try the end mill method and drill larger. The hole is currently drilled for 10-24 screws, but I also have 1/4-20 screws on hand which would work just as well.

metalhead357
11-30-2006, 1:20 AM
GO SLOWER next round, and use more oil. Use a lot more back out action than trying to cut full swaths. I know it can happen on just about anything but was your hole cut/drilled to the proper size before attempting to tap? ((ask me how I know this:o but no, thankfully, not on gun or gun parts)).........

Good luck

NeoWeird
11-30-2006, 1:48 AM
That reminds me, the AK trunion seemed to make chips that did not want to break easily. As you turn into it, you will feel the chip build and then when you let off of it make sure you go back far enough to hear the chip break. Usually I only need to go back a quarter to half turn back to get it to break, but on the AK trunions it seemed to almost go a complete turn back before it would break towards the bottom. Might keep that in mind next time. Just because you feel the tap go free when you back off doesn't mean you broke the chip. Also there is nowhere for the chips to go, so maybe back the tap out 60% of the way down and blow it out before finishing. Wouldn't hurt next time.

ZapThyCat
11-30-2006, 6:25 AM
Folks, lets not use the term "SHTF" for stupid issues. When SHTF happens people will be dying by the dozens or hundreds, that's far different than a broken part in a gun.....

BigMac
11-30-2006, 7:52 AM
GO SLOWER next round, and use more oil.
Good luck



No, do not use oil. Use cutting fluid. This was the advice given me be a machinest that removed 3 taps for me.

I bought some stuff called Rapid Tap, in a little yellow lighter fluid looking can, at OSH and it works great.

Charliegone
11-30-2006, 10:30 AM
My suggestion..get some cobalt drills (hard metal kind) and drill through it. Worked for me when a piece of drill got stuck on the rear trunion on my ak. Went right through. Also, do get cuttiing fluid. I got ace stuff which is pretty good. Plus...these drills will cut through metal like swiss cheese, so please be careful.

saki302
11-30-2006, 12:50 PM
I busted out a tap by using a hardened punch and a medium weight hammer. A few whacks and little teeny pieces came out. And it was also in a trunion :P hahaha

-Dave

DRH
11-30-2006, 2:01 PM
Spend the $20-25 bucks for a broken tap extractor and also buy a few spare sets of fingers at the same time. It makes easy work of getting the broken taps out.

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1737705&PMT4NO=14935705

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1737834&PMT4NO=14935705

jumbopanda
11-30-2006, 2:29 PM
The reason it broke was because I kept turning it after it hit the bottom, not because I didn't back it out frequently enough or I went too fast.

I thought to myself "just a little more..." and then....ARGH! :mad:

jumbopanda
11-30-2006, 2:33 PM
My suggestion..get some cobalt drills (hard metal kind) and drill through it. Worked for me when a piece of drill got stuck on the rear trunion on my ak. Went right through. Also, do get cuttiing fluid. I got ace stuff which is pretty good. Plus...these drills will cut through metal like swiss cheese, so please be careful.

The problem with using drills is that the surface of the broken tap is very uneven, which causes the bit to wander off center.


DRH, I've seen those, but why are there always ones that are less than $1 while another of the same size is ~$12?

DRH
11-30-2006, 4:43 PM
The $12.00 one is the tool and the .87 cent link is for an extra sets of fingers of which you should buy multiple sets with the tool (one set included). They are hard and break easy. I bought four more sets later and the shipping was double the price of the fingers.

M. Sage
11-30-2006, 6:24 PM
GO SLOWER next round, and use more oil. Use a lot more back out action than trying to cut full swaths. I know it can happen on just about anything but was your hole cut/drilled to the proper size before attempting to tap? ((ask me how I know this:o but no, thankfully, not on gun or gun parts)).........

Good luck

+1 to slowing down. Cut for only 1/4 turn at a time, stop, back up one full turn, then go 1/4 turn past your last stopping point. You'll break the chips off at a manageble length instead of loading the tap up horribly (jamming it in the hole and making it break).

It's not a horrible idea to back a tap most of the way out once in a while and clean the chips out if they're building up and/or it's a deep hole. An aerosol spray of something like WD40 can be used to blow them out the bottom of the hole, if this is a through hole you're tapping and not a blind hole.

jumbopanda
11-30-2006, 7:44 PM
Lets change the topic for now. I'm trying to drill out the other trunion holes and things just aren't working out. I'm using 1/4-20 screws, like the guy at www.gunsgutsandgod.com, which are slightly larger than the rivet holes and require a little bit of drilling into the trunion. Unfortunately, the trunion is a tough mother****er and the drill just grinds up against it. I've tried TiN coated HSS bits, and cobalt bits, two different speeds, and POURED oil all over the damn thing. No luck, at most the drill goes about 1/8" into it and then just stops and starts to grind. Am I doing something wrong or am I just destined to never build an AK?

Charliegone
11-30-2006, 7:59 PM
Oh yeah I forgot to mention. I pounded the drill flat on top so that I could drill on it.:D

Just go slow. I always use about 2 drills for the back, the cobalt ace drills worked great for me. Also I would suggest you also use a punch once you get half way through. I know its a b**** but its just easier that way, just to get it moving. Best to make the hole almost the size of the rivet to punch out.

rg_1111@yahoo.com
11-30-2006, 8:09 PM
Oh yeah I forgot to mention. I pounded the drill flat on top so that I could drill on it.
I think you mean tap.

metalhead357
11-30-2006, 8:39 PM
No, do not use oil. Use cutting fluid. This was the advice given me be a machinest that removed 3 taps for me..

Same stuff 98% of the time...just different viscosity; but really ANY kind of lubricant will work. Machining tapped parts (tapping via Milling machine, lathe, etc) usually do require a better/dedicated cutting juice but for the home builder 3in1 will even work, so will WD 40..........

Charliegone
11-30-2006, 9:57 PM
Oh yeah I forgot to mention. I pounded the drill flat on top so that I could drill on it.
I think you mean tap.

no...I mean pound.:D

Ok this is what I did exactly, just so nothing is forgotten.
(starting from the broken drill in the trunion) I first got a punch with a flat tip and pounded the drill on the top of it flat. It just needs to be flat enough so that it can be drilled through. After that, I drilled on the other side. Then I drilled through the drill and that was it. Went right through. After that I just pound the outter part of the rivet out.

jumbopanda
11-30-2006, 11:09 PM
Another concern: should I be worried about drilling too deep into the front trunnion? I drilled into the barrel, not all the way through it, but maybe 1/2-3/4 of the way into it. Is this a bad thing?

Charliegone
11-30-2006, 11:24 PM
Another concern: should I be worried about drilling too deep into the front trunnion? I drilled into the barrel, not all the way through it, but maybe 1/2-3/4 of the way into it. Is this a bad thing?

Yes! Be very very careful with the front trunion. I suggest you drill about the size of the udrive, or screw whatever you are using. DO NOT GO OVER!!! This can be really really bad. I'm talking explosion when you shoot. I think just a little tiny bit is ok...but 1/2 seems to be too much. I would think it would be ok to fill it up...but don't take my advice, maybe someone else can chime in this part.

jumbopanda
12-01-2006, 2:23 PM
:eek: :confused:

Charliegone
12-01-2006, 2:38 PM
:eek: :confused:

Don't worry, there is always a solution to everything. A new (or used) barrel will fix that. If I were you, I'd just buy a new front barrel assembly (which runs like 60 to 50 bucks on Gunbroker I think.) No matching numbers, but better than nothing.:D