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2XTM 9mm Build Progress

11K views 65 replies 13 participants last post by  2ndAmendican 
#1 · (Edited)
Thanks to all who offered advice, and especially to Zoom6Zoom who sent me the original PDF files from Lichtenberg Research. They helped a ton!!!!!!!

Here is the progress so far:

Bent up a piece of .050 mild steel that I cut out the rough opening for the 2XTM magwell prior to bending. (I use a Tapco flat as a template, and scribe onto the plain sheet metal.) Trimmed to rough size, bent the top rails in a hydraulic knife edged type bender at work. drilled pilot holes everywhere I needed them, cut out for magwell, pistol grip nut, and trigger so I could put it in my poor mans jig. Set the outer die spacing for the .050 flat, and bent it up, nice and square, with great corners. I was worried about how well it would turn out with the large magwell cutout and not being able to use the forward most bolt through the inner clamping die on the bending jig. It turned out great!!!!!! Temp installed the magwell with 2 8-32 screws in the aft holes for the front trunnion. In general it fits good. It will still need lots of trimming and fitting once I have a couple of Suomi drum mags to start fit checking. I went ahead and finished drilling up the receiver, temp installed the center support, double checked the FCG fit, selector lever, top cover, etc.... It all looks great.

I mocked up a few parts on it just to get an idea of what it will look like. This is by no means the furniture that will go on it. I haven't decided on that yet. It's just there because it was the closest items at hand.

Crap tried to load a pic and it's too big!! Will post a pic as soon as I can resize it.
 
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#3 ·
I have the pic on my work computer, and today they have me stationed on the other side of the base, dangit! I'll see what I can do though.
 
#7 ·
Same as any other build from a flat. Ejector tip and FCG holes with a MAPP gas torch.
 
#12 ·
Hey guys, mild steel doesn't harden from simple heating and chilling. It lacks the carbon content. Case hardening may help with special surface chemical treatment (carbon rich stuff).

VD
OK VD, I'm confused now. So the heat treat method that I, and virtually every AK home builder (that builds from a flat) has been using does not work???? Same procedure from Toten Kopfs CDROM, and all of the various internet published procedures. Basically heat area to cherry red, then quench in oil or water. Remove scale with a wire brush then heat area to a grayish purple color and let air cool.

I've built about 5 receivers from 4130/4140 sheet from McMaster Carr for myself, and bent a few blanks from this for other folks on Gunco, and have had no problems(both .040" and .050"). Not to mention all of the Tapco flats, and AK Builder flats that I have done this method on. Now mind you, I don't have thousands of rounds through any of my 25+ builds, so I don't know how long it takes for a hole to egg out, or an ejector tip to get peened into oblivion. Have there been failures of these areas from the procedure that I use? If so, I'd sure like to know and change my procedure.

I have actually been looking at some of the case hardening products, (Brownell's and Cherry Red) mainly for firing pins, but was thinking about trying it on the FCG holes as well.
 
#11 ·
Lets try this again:
 

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#13 ·
I've built about 5 receivers from 4130/4140 sheet from McMaster Carr for myself
Hey guys, mild steel doesn't harden from simple heating and chilling. It lacks the carbon content.
The difference is "mild steel" vs 4130/4140 (and similar steel), they need to be hardened in different ways.


The build is looking good, I got to stop screwing around and get mine done.
 
#14 ·
The difference is "mild steel" vs 4130/4140 (and similar steel), they need to be hardened in different ways.


The build is looking good, I got to stop screwing around and get mine done.
Oh, ok, I see. People are differentiating between "mild steel" and "4130/4140 steel". I have always used the term "mild steel" to include 1018, 4130, 4140, and a few others that are easily formed, and need to be heat treated to "fix" their final shape and or strength/wear properties. It has never been questioned until today. Been using that right or wrong for 30 years, in the aviation industry no less. LOL. . I guess I will have to be more specific in the future.

Definitely gotta get yours going Coils. You gonna use that blank I bent up?? If so it should work out great. I was concerned about where the jig through bolt went, and whether it would interfere, but from what I see on mine, it should be dang near perfect.
 
#15 ·
Just trying to clear up the confusion :D
Well all the different grades of steel gets me confused, too many out there and they all have different characteristics.

Yes I was going to try using one of those blanks I got from you. Got to get some other projects (non-gun related) out of the way first.
 
#17 ·
Thanks guys!! Unfortunately some major medical bills just hit the mailbox and the project is stalled. I need to buy a couple of drum mags because the next step is to fit the mag(s) to the magwell, before fitting the magwell to the receiver. Unfortunately that aint gonna happen for awhile, unless somebody has some extras they are willing to let go real cheap. Dangit!!!!
 
#19 · (Edited)
chris, i finally got together with my buddy and got you that spare beater trunnion i'll mail it out today or first thing in the morning

edit: dang that thing's itching for a galil stock lol you know turbo has the trunnions he made for an akm that take galil stocks :) they're great i bought a couple but had him narrow them down for 1.5mm receivers
 
#20 ·
Thanks Johnny. Yeah you can set it up for both drums and sticks, but it's easier to go drum only. CFS has them for $24.99.

Thanks Justin. Yeah it would be great to have a Galil trunnion/folder on there.
 
#22 ·
Well, I have a few parts on the way thanks to Jreifsch80. Also was able to swing 2 Suomi drums from CFS for $24.99 each. Need those to fit the magwell to. Then fit the magwell to the receiver. Now I need a cheap trigger guard. Might make one if I can find the drawing again. Machine shop still has my EOD bolt, so he can give me a quote on 10 each partial copies. We decided to do the main body of the bolt/carrier only. The tube for the recoil spring is welded on after the fact, and the end user could take care of that. We'll see.
 
#28 ·
Coils, as soon as I get the pricing, I'll let everyone know. I'll start a new thread just for the bolts.

Well, yesterday I cleaned up and modified the front trunnion that I got from Justin. I drilled up the receiver for the front trunnion, threaded it 10-32, and installed it. I temp installed the barrel and gas tube to check everything. Looks good. The drum mags are due in today, so I can fit the mags to the magwell. Then I need to spot weld the rails in, and install and fit the magwell permanently. Smartbomb is sending me a fixed stock rear trunnion, a recoil spring assembly, and a trigger guard. Thanks Smart!!!

The big item is obviously the bolt/carrier. I think that temporarily I'm going to use my EOD bolt. The ones I'm having machined are basically the same dimensions, so once the replacement comes, it should swap out fairly easily.

Thanks again to all of you guys who have helped with spare parts, etc.... It's much appreciated!!
 
#30 ·
chris. its all good! parts should be on their way soon. keep me in the loop on the bolt. i want to try one.
Thanks!!! Will definitely keep you in the loop.

Update: Got my mags yesterday from CFS, and cleaned them up. I like the way they work. Test fit them and both of them fit pretty good right off the bat. I don't think that I will have to remove any material from the bottom of the magwell. Using my EOD bolt at the moment to test, and the bolt is wider than the slot in the feed tower (if you can call it that) on the drum. I need to investigate further, and see where I'm going to remove material. Probably a little from both the mags as well as the sides of the bolt. I need to be careful though, as the bolt is designed to work with a double feed mag, and the drum is single feed. Don't want to take too much off where it won't properly strip rounds from a double feed mag.

Here's a pic with the mag inserted:
 

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#33 ·
Scott, I think it was 9.5 oz, IIRC.

Viper, I did a fair amount of work on it last night, and discovered that my issue isn't the width of the feed lips on the mag. That is ok, and actually can not be changed via clearancing the mag side, without seriously affecting how the rounds hold in place at the top. Any rate, at the time I originally thought there might me an issue, I had not heat treated, spot welded the rails, or installed the center support. Once I did all of that yesteday, plus some final fitment of the magwell itself, everything came into better alignment.

I use the AK-Builder top rail scribe jig, and I always cut a little long to the outside of my scribe line. I hadn't shaved it down far enough, so it was pushing the bolt carrier to the left, out of alignment with the mag. Once I file that down, it should be fine. Thanks for the input.
 

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#35 ·
must have front sight/gas block


me likey. what trunnion/tube is that?
I "think" its a Galil. I picked up the barrel assy and magwell from Pat Simpson. He had already done some work with it. The front sight/gas block was temp installed, as was the lower handguard retainer. I really like the look of the Galil front sight assy. I think I'm going to switch top covers with my gas op x25, because I had installed a home made semi-Krink style rear sight on it, only farther aft than on a Krink. I think it would line up and work perfect with the Galil front sight.

The trunnion is a standard European AKM, that had been hacked all to hell. Justin sent it to me, and it's perfect for my needs.

I don't have too much left to do to it this evening till I'm outa parts. Big issue is still waiting on a quote from the machine shop. Hopefully I'll get it on Monday. Even though I am dealing with them as a paying "customer", he is still kinda stuck in that "doing it free for a friend" mode, and seems to be putting the bigger jobs ahead of mine. It's understandable, as their bread n butter is doing a bunch of stuff for the Michelin tire plant. I'm just impatient.
 
#37 ·
cool. i like the cleanliness of the top half minus the rsb. your parts should ship today. i cant ever seem to get to the post office during the week.
Yeah me too. It just looks right on there.

Thanks man. I really appreciate the help.

I had some better pics showing the drum/magwell/bolt relationship, but for some reason when I try to save them onto my computer or thumbdrive, the dang thing won't let me. Sucks, as they were clear as a bell.
 
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