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Another DIY AR lower option?

Discussion in 'Maintenance & Gunsmithing' started by Diamondback, Jun 6, 2016.

  1. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    Gents, I know this mill-drill-tap-ream-and-screw option for an AR lower's been around a while thanks to Weaponeer Forum, but was wondering if it lived up to the hype about "so easy an untrained monkey could do it with hand tools."

    Bolt-together AR-15 lower receiver: no 3D printer necessary (http://www.guns.com/2013/12/06/bolt-together-ar-15-lower-receiver-3d-printer-necessary/)

    Looks like some simple plate-steel would work for materials...
    -1/8 plate: triggerguard, magwell sideplates, FCG-well bottom, receiver sideplates
    -3/32 round bar: buffer retainer
    Grip mount looks like 1-3/4x2-3/4x3/4 billet, buffer tower 2-1/4x1-1/2x1-1/2, magwell back 1x3/4 rect. bar, rear 1x5/8 bar.

    @bolus , @IronMonster , any of you other DIY PCR/blank/80% guys, if y'all would trust this design anything I'm not seeing that I'd need to look for at the scrap dealer or Metal Supermarket? Also, any suggestions on a "hand tools" mill substitute that even a complete idiot could turn several hunks of plate metal into a viable lower? (My grandfather's body wasn't even cold before my uncle was tearing his machine shop apart and giving pieces away to buddies or hocking it for rotgut money, and now that he too has passed I doubt any will be coming home so I have to start building my own workshop from scratch.)
     
  2. bolus

    bolus Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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    Are you buying it as a kit or making each of the parts yourself? By the technical drawings on that link there are several parts that would need a skilled machinist or a CNC mill to make like these

    2.png
    2007-10-17_131429_AR_15_Scratch_Built_Receiver.png

    Otherwise the design looks fine. All the forces are at the buffer tube connector and that looks sturdy

    For me, there is no way I could build this from scratch. a regular 80% AR receiver would be so much easier for me
     
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  3. rick benjamin

    rick benjamin USA, Or, Damascus Secure the drama Silver Supporter 2016 Volunteer

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    There's a scary big and oily machine that "broaches" the AR magazine well, already done in an 80% lower. The machine is more expensive than all my allowances.
    Finished my lower with a HF hobby mill. Took my time, followed instructions. Still left a few oops marks in the trigger control group pocket. Bought the mill, then the bits, then the R8 tapers, then the runout dial, then the..$$..$$..Because I tinker.
     
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  4. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    @bolus , completely from scratch. I figured buffer tower and grip mount would be the nasty parts to do. Obviously there's no ATF Determination Letter for this, so I doubt anybody could do a kit but I'd expect the sideplates to be the "controlled parts" in such case. (Not a lawyer though, nor do I pretend to be able to make sense of the BATF***ers' multiple-reversals-before-first-coffee-break brand of Orwellian Doublespeak.)
     
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  5. Ura-Ki

    Ura-Ki Sub Light Speed Well-Known Member

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    I see no problems IF you had a really good drill press with X-Y axis cross slide vice and the milling bits you needed. A bigger concern ( that Bolus pointed out) would be the buffer tube milling, that would take a roto broach and a means to thread. From there, I can see some work in the mag well area as a challenge, but I think it could be done. Make sure to use high quality hardware AND lock tight. Honestly, I don't really see going that far when the 80% lowers are as cheep as they are, especially once you have the tooling the kits come with! From the ATF side of things, you are all ready at a 80% and thus exempt ( unless you do a sbr or other NFA) so you gain nothing there as far as the rules go! But, I do like the idea of a do it your self lower, kind of a neat look to it! Personally I would bolt it all together then weld it up solid and remove the hardware and mill it, sort of like a JP custom AR look! Keep us posted, I like the idea.
     
  6. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    One of the things I like about this one is if you pull the screws it's all a bunch of scrapmetal. Or, since some parts like the buffer have been SLP'ed before, is there any potential hazard I'm not aware of in mixing metal and ABS parts?

    In the more traditional vein, what would you BTDT's suggest for an "untrained monkey at kitchen table" jig and blank pair?
     
    Last edited: Jun 7, 2016
  7. Ura-Ki

    Ura-Ki Sub Light Speed Well-Known Member

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    These builds are fun to do, but require a fair amount of investment in tools and a way to drive them. That takes the untrained monkey simplicity out of the deal. Fortunately, once you invest in the tool, it opens up other builds to you. Most take special jigs and tools that can be reused over and over again! As an example, the ever popular 1911 build will set you back close to $500 in tools with over half devoted specifically for the 1911 platform only, but once you have all the tools and jigs, the net cost is a lot less with each successive build. The AR build is actually a lot less complex and less Tool heavy in investment, mainly just the milling bits, so the unit cost once you have the jigs and bits is quite a bit less.
     
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  8. Capn Jack

    Capn Jack Wet-Stern Washington Bronze Supporter Bronze Supporter

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    :( The story of my life Rick :rolleyes:
    But it keeps me out of the bars, I don't smoke and the wife
    says, "It's cheaper than a Mistress." :eek: :D
     
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  9. Capn Jack

    Capn Jack Wet-Stern Washington Bronze Supporter Bronze Supporter

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    Bolus,
    Just carrying this discussion a little further into the "Blacksmith's Shop", (As my old Machine Shop Instructor used to say.) Couldn't the buffer tube support be made out of a large nut and welded onto a support?
     
  10. bolus

    bolus Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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    Yes, the ar15 flat kit actually says that people often just weld the castle nut right to the frame so they dont have to tap the threads. If you are able to weld, then this kit would be far the easier approach for an attempt

    plus at $28 you are not investing anything significant either.
    The Flat Spot - Innovative products for firearms builders and more! (http://www.theflatspot.net/ar-15-receiver-flat.html)

    6380789_orig.jpg
    1042735_orig.jpg
     
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  11. Ura-Ki

    Ura-Ki Sub Light Speed Well-Known Member

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    Now that is a far more reasonable kit then any I have seen so far! A long as you can weld, that should be about the hardest part of that build!
     
  12. bolus

    bolus Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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  13. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    Interesting, @bolus , I was just thinking about that one as another possible--doesn't have the "hide in plain sight as scrapmetal" appeal, but if it can be silver-soldered and pass the durability test... how's it been holding up for you in testing?
     
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  14. bolus

    bolus Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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    I have not shot it. I was not willing to blow off my fingers :) My silver solder approach was a big joke just to see if it would function. I did learn how to silver solder with the process though and fixed a rear mosin sight from what I learned. so it was not a complete waste

    the guys at weapon'd guild have finished them nicely and they function.

    190729-ae7a44283b865d12fdf5d99250d54941.jpg
     
  15. Ura-Ki

    Ura-Ki Sub Light Speed Well-Known Member

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    I see no reason not to silver solder one together! In fact, Carbon Arc soldering would be just about as strong as welded. I have a TIG and that would be used for most of a build, But I like the aspect that it is not required and that just about any one can do it after they learn the basics of soldering! I wouldn't be too worried about the strength of silver soldering, but I would take one extra precaution, after soldering ( assuming you used a torch) I would put in an oven at 300 deg for an hour, then turn the oven off leaving the lower to cool to room temp. This way, the metal relieves heat tension, and could be further heat treated if desired, the point being that high heating from soldering or welding will make the part brittle unless it is treated after. Thanks Bolus for the link and photos!
     
  16. bolus

    bolus Portland Gold Supporter Gold Supporter 2015 Volunteer 2016 Volunteer

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    Thanks for the info. This was just a joke build because it was $28 and I wanted to try and make the ugliest AR receiver every made. I think I got pretty close. The silver solder was difficult with just a butane torch so it is holding together but I think it would break the moment I shot it. Its definitely not "properly" soldered.

    but its a cool little inexpensive kit to play around with.
     
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  17. Capn Jack

    Capn Jack Wet-Stern Washington Bronze Supporter Bronze Supporter

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    Oh man...Just add a "Franken Mag." and you're in business.:eek:

    I've got to stop watching this post.:(
    I have enough projects....:confused:

    Mom always used to say, "Quit picking at that. You'll only make it worse".:rolleyes:
     
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  18. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    Guys, just found a kinda neat looking little 3d printer that's on sale right now. What do you think about this?

    The Micro by M3D |The First Affordable Consumer 3D Printer | 3D Printers | 3D Printing | 3D Printing Filament | Affordable 3D Printing (http://www.printm3d.com/themicro/)

    Regular price is $450, I have a coupon for $100 off. While it can only print an area 109x113mm below 74mm high and 91x84mm above that... it's probably not enough for a complete lower but might be just enough for a buffer tower.
     
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  19. edslhead

    edslhead Vanc Gold Supporter Gold Supporter Silver Supporter Bronze Supporter

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  20. Diamondback

    Diamondback A cold, wet green Hell Well-Known Member

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    Shades of In The Line Of Fire there, @edslhead ? LOL
     
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