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1/2 scale AR-15

Discussion in 'Rifle Country' started by MachIVshooter, Oct 6, 2014.

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  1. thefish

    thefish Member

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    Can we look forward to a test fire video?

    This is an awesome project!
     
  2. MachIVshooter

    MachIVshooter Member

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    That is not permanent, just haven't got around to turning one. Given the scale, rather than try to use a clip with a <.065" ID, I'm just going to machine a piece of music wire with a collar.

    When it's done, you bet! But I still don't have a response from ATF yet, nor have a chamber reamed or profiled the actual barrel
     
  3. MachIVshooter

    MachIVshooter Member

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    Needed a break from my 1/2 scale project, which is basically done except for anodizing and the real barrel. Today we took it down a notch, whipped up another billet lower. This one took about 6 hours as it sits, though I still have lots of finish work to do:

    7e4dd5d5-3f31-495d-b677-3a44f8a07379_zps7dd6669d.jpg

    3fd0e8f6-1c23-44b1-bdb1-10d7f997ec00_zps80672c36.jpg

    IMG_1261_zps650f7c9d.jpg

    Still a little rough, but there is a good reason tool marks look much worse on this one; the size:

    IMG_1262_zpsf54f582b.jpg

    IMG_1263_zps6f473e7f.jpg

    This critter is 1/4 scale, measuring 1.941" long and weighing in at a hefty 6 grams (0.2 ounces). The widest point of the FCG pocket is .172", take down pins are 1/16", and the trigger & hammer pin holes are 0.039". RE is threaded 5/16-40.

    Unlike my 1/2 scale, this one is pure novelty; I have no intention of developing a 1.39x11.25mm round.
     
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  4. Bobson

    Bobson Member

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    For shame!

    Is it a pure novelty that will eventually be an entire (1/4 scale) rifle?
     
  5. MachIVshooter

    MachIVshooter Member

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    Not likely. The challenges in 1/2 scale were difficult to overcome, some of those may be insurmountable in 1/4 scale without spending a ton of money. Finding 0.5mm compression springs, for example.

    No, this was more for S&Gs. Probably just hang it on my keychain.
     
  6. Bobson

    Bobson Member

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    Understandable. Pretty cool either way.
     
  7. USAF_Vet

    USAF_Vet Member

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    I want one of those 1/4 scale lowers as a keychain!
     
  8. bannockburn

    bannockburn Member

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    Would most definitely make for a very cool keychain addition!
     
  9. HOOfan_1

    HOOfan_1 Member

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    if the 5.56 is called a poodle shooter, that could be ant artillery
     
  10. rbernie
    • Contributing Member

    rbernie Contributing Member

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    This is officially the coolest thread EVAR. :D
     
  11. UpTheHill

    UpTheHill Member

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    I would definitely pay for one of these as a key chain.
     
  12. mainecoon

    mainecoon Member

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    What about a 1/4 scale Warthog gun?
     
  13. glockman19

    glockman19 Member

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    WOW...I am totally impressed and blown away at your workmanship.

    IF you ever go into production on a .22lr model I'll be first in line.

    Thank you for sharing.
     
  14. blueskyjaunte

    blueskyjaunte Member

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    At 6 hours of machining time, that's one hell of a keychain! :D

    Great work!
     
  15. MachIVshooter

    MachIVshooter Member

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    Looks much better after a couple hours of stoning and sanding:

    d0e7e3dc-0afa-45c0-a1ab-90abe2898d8a_zpsdf51a645.jpg

    67089036-dd19-421e-b682-241e48b615fa_zpscfd22e2c.jpg

    That's probably what'll happen with it.

    I can't imagine very many folks willing to pay what it would cost for me to build these working for minimum wage on my machines and recouping the cost of broken cutters (just plain happens with 1/16, 3/64 and 1/32 sizes); these things would be ~$80-90.
     
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  16. jell-dog

    jell-dog Member.

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    MachIV,
    Your 1/2 scale is truly a masterpiece!
    This 1/4 edition is absolutely amazing:eek:
    I can't believe you would offer them at $80-$90:scrutiny:
    Even at $100 each, something like this is so unique I think you would be making more of them than you think:D:D
    Maybe a numbered limited edition? Say 100?
    After 100 you may be sick of making them:barf:
    OK. 50 Numbered Limited Edtion.
    If you do offer them in a limited number I want one!!!
    Since 2 others have voiced a willingness to purchase one, put me on the list for serial #007:D:D:D
    jell-dog
     
  17. OldBrownDog

    OldBrownDog Member

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    I know I've paid $75+ for hand forged wrought iron bottle openers. I suspect there'd be more of a market than you think.
     
  18. MachIVshooter

    MachIVshooter Member

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    Well, I have plenty of 3/8" 7075-T6, although I'll be waiting ~ a week on the replacement cutters, as I'm down to just one 4 flute 1/16", and killed the last of my 3/64" and 1/32" end mills.

    I have considered making them out of D2 tool steel and hardening them as well, for the durability factor and the ability to blue them nearly black. However, it's messy with the lube requirement (I cut 7075-T6 dry), harder on cutters, and the finish work would take twice as long. I'll probably do at least one from tool steel, though, see how it goes.

    I also plan to build a 1:1 lower out of either 4140 or 416 stainless, but that's a spendy hunk of metal. Always wanted a steel AR, though (can't afford a Turnbull, either)
     
  19. HisStigness

    HisStigness Member

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    If you are considering making more of the 1/4 scale lowers, you could make it out of softer 6061 aluminum. This would cut down on your cost of materials and cost of tool replacement. Unless would be buyers are concerned about their key chain being mil-spec.
     
  20. jell-dog

    jell-dog Member.

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    ^^^^^Ya, what he said:D
     
  21. MachIVshooter

    MachIVshooter Member

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    Actually, 7075 or 2219 are preferable. 6061 is too soft and sticky to cut dry, clogs the flutes and leads to many broken end mills. Even TiAlN coated cutters are not immune. Only reason to work with 6061 over 7075 is cost (or a welding requirement).
     
  22. HisStigness

    HisStigness Member

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    Well that just proves what I suspected... I know nothing about machining.
     
  23. Whacked

    Whacked Member

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    Make that 1/4 scale able to open beer bottles and you won't be able to make enough
     
  24. rcmodel

    rcmodel Member in memoriam

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    A GI hinged winter trigger guard should just about do it!

    A buffer tube that screws off with a Fisher Space Pen refill in it!

    Bottle opener, writing instrument, and Kuboton all in one!!

    rc
     
    Last edited: Dec 11, 2014
  25. MachIVshooter

    MachIVshooter Member

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    lol. It's all good. Not so long ago, I would have deduced the same. It's only having worked with the various alloys that has shown me harder materials aren't necessarily harder on cutters. Generally speaking, the harder the alloy, the less prone it is to clogging flutes and galling. Now, with steels, you need lubricant/coolant almost universally. But the hardest aluminum alloys cut pretty well dry, unless you're trying to bore or make heavy full diameter cuts, where the chips build up and generate enough friction that even 7075-T6 will stick. Chip clearing is paramount. Aside from that, you just don't want to dwell, as it builds up heat, which is what dulls cutters.

    Cost-wise, if you're dealing with substantial pieces, 6061 can offer considerable savings. For these little pieces, though, the difference is truly negligable. I get 8"x16" pieces of 3/8" 7075-T6 for $20; I could theoretically get better than fifty 1/4 scale lowers from one sheet, making materials only $0.40/per. It's the 2 or 3 snapped micro cutters at $5-$8/ea that cost me. And it's really, really hard to feel when they're loading on a 9x48 mill that weighs more than a Camry.
     
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