Flat steel puzzle piece AR lowers

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Has anyone ever assembled an AR lower from one of those puzzle piece kits?

Seems like an easy way to waste $30, but also seems like with adequate welding skills and a little patience, you could turn out an ugly as sin steel AR lower/ nifty paperweight.

I'm thinking about dipping into my discretionary fund to pick one up.

I need another project as my scrap yard, left handed Sterling is on hold until I get a magazine.
 
SuedePflow said:
Kind of odd that the seller is based out of Kansas but charges me Michigan sales tax.
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Thank Snyder for that. He's been hammering online retailers to collect state sales tax, or better known as the "usage" tax. Like we don't already pay enough.

Ordered my kit. Should be a fun side project.

I decided to do one A) for the challenge, B) I have welders, but no mill, router or drill press stable enough to handle lateral cutting without wrecking the bearings C) it's the least expensive option.
 
desidog said:
Pictures please!
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I'll be posting step by step build pics once it's done. So far, all I've got finished are the barrel, front sight, about 80% on the receiver (Still need a flat spot Uzi mag well, which aren't in stock). Once I get the mag well mounted and barrel actually installed, I can finish the bolt. I have the FCG designed, just needs to fabricate it which I can't do without the finished bolt.

This will probably be a months long project.
 
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Flat Spot kit welded together.

I still need to grind some of the boogers down, smooth it all out and figure out some kind of finish.

IMAG0062_zpsjpg8nknf.jpg

IMAG0063_zpsqocp7kqa.jpg

I'm thinking A2 fixed stock for this build. I may even convert the magwell to 9mm.

Anyone make a 9mm bolt to work from Uzi mags? My other project will use Uzi mags, would be nice to share them.
 
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Why weld? I could flow braise a heckofalot neater than attempting to weld that sandwich.

Kinda like some .30 carbine lowers produced in WW2...................ah, hell, now you've got me ordering one of the things!!!


Y'know, for that matter I'd bet that JB weld oughtta work too!!
 
Why weld? Why not? :p I don't use my welder at home much, and it was a nice weekend that I actually had off, so it was a fun few hours.

I'll probably use JB Weld as a filler for some of the gaps and help smooth everything out. It's a lot less ugly than I was expecting now that I got the boogers ground down and filed somewhat smooth. I need to file a smidge in the mag well, it's a bit tight for an AR mag, and wouldn't fit a 9mm block, either.

Brazing would work, but I don't have an oxy acetylene torch and brazing rod at home. I'd have to use the one at work, and they tend to frown on government projects.

I'll tell you though, this lower is a sturdy beast. I want a 9mm carbine, but I may use this as the base for the .450 Bushmaster build I have planned.
 
I wonder if silver solder would be sufficient? Could then be done with a MAP torch...
 
Grip installed, mag well smoothed and mag inserted. Just need an upper, an LPK, and a stock.

IMAG0064_zpszfp2ppl9.jpg

IMAG0065_zpswwrj2rao.jpg

IMAG0066_zpsq9tytssd.jpg

Satisfied with how it's coming along.

Still needs some minor tweaks before applying the finish. I was thinking truck bed liner, but I may take a torch to it for some rainbow swirls, or just some good old fashioned cold bluing.

Looking less and less ugly.

Mags don't drop free, need to remove a bit more material for that. But a slight tug removes it no problem.
 
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Grip screw is 1/4-20.

For the buffer tube, I'm going to weld the castle nut directly to the tower after boring it out to fit.

I have some 1" ID steel electrical conduit I may use in lieu of a mil spec buffer tube. Its the same ID/OD (or close enough) as a buffer tube, so I may just weld it directly to the tower, and figure out a stock from there. The more I think about it, the less I want it to look like anything remotely off the shelf, and as "scrap yard" as possible.

The pivot gap is still a hair tight, so I should be able to fit an upper on it soon. I set it in place as close as possible, and the bolt and charging handle ride smooth through the tower, so everything lined up great.

I am going to have to figure out something for the safety. The detente divot on the safety is inside the receiver in open space. Thankfully I haven't drilled the detente hole. Gonna have to put my thinking cap on to solve this problem.

I'm using shoulder bolts for the take down pins, so no need for detente holes drilled there.
 
Grip screw is 1/4-20.
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1/4-20 is fine, but spec (and what will come in the LPK) is 1/4-28

I wonder if silver solder would be sufficient? Could then be done with a MAP torch...
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You would have a heck of a time heating that much steel to 1,200* for silver solder with a plumber's torch.

Brazing, gas welding or TIG are the way to go with these. As USAF has shown, a MIG/wire feed will certainly work, but leaves you with a lot of clean up.

Finishing off one of the 80% receivers available today is so easy using a router based jig that I cant understand why anybody would take on one of these weld ups unless it was just for the challenge.
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If it were all about expedience, we'd just buy $39-$49 blem lowers. Some of us just like to make things, even if it's not terribly practical.
 
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Yesss! I was thinking silver solder. Will make very neat edges. I'm a fairly good welder(as a profession actually) but I wouldn't like dobbin' around on it with a Mig and surely not stick, Tig would look nice though, unbuffed even.

* Looking good SuedePflow!
 
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A buzz box is all I have. What about tack welding with 1/16" 6013 electrodes? I did a couple of Mauser bolt handles that way, and they turned out pretty decent.
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Will it work? Yes.

Will it be ugly as sin? Undoubtedly.

I can barely fathom the amount of building up and grinding down you'd have to do using a stick welder to make it not look like an AR lower-shaped turkey turd.
 
The more I think about it, the less I want it to look like anything remotely off the shelf, and as "scrap yard" as possible.
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The Khyber Pass comes to mind...
 
I was thinking more along the lines of the AK built from a Shovel.

Does anyone make a steel upper? I've already nicknamed this "Heavy Metal" so a steel upper would fit the profile.

I have a 1/4-28 tap, too. Don't know why I didn't think of that. Oh well. Not a big deal for my purposes.
 
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