Help support WeTheArmed.com by visiting our sponsors.

Author Topic: DIY AR lower project  (Read 4336 times)

Cookie

  • Member
  • **
  • Posts: 335

  • Offline
DIY AR lower project
« on: September 07, 2013, 05:24:32 pm »
So I'm taking a stab at machining my own AR lower, using the design from a thread on CNC Guns:

http://www.cncguns.com/forum/index.php?topic=940.0

The CNC mill I'm using is quite a bit larger than the Taig that was used for the original guy's build, plus I have an automatic tool changer, so the milling goes very quickly once the programming and fixtures are sorted out. I'll be starting on the other half sometime next week.

This is what I have so far:


I'll probably put a standard 5.56 upper on it when it's done, nothing fancy.

I am planning to do a bolt-action .50 BMG at some point, and will probably use a heavily modified version of this design for the fire control housing.
"Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

WeTheArmed.com

  • Advertisement
  • ***

    Adskii

    • Senior Member
    • ***
    • Posts: 843

    • Offline
    Re: DIY AR lower project
    « Reply #1 on: September 08, 2013, 02:07:37 am »
    What does a one-off like that cost to produce? I know you can't make them for anyone else... but I'm curious (and cheap) and I have had the idea to have one milled or mill it myself, but have no idea about costs.

    Cookie

    • Member
    • **
    • Posts: 335

    • Offline
    Re: DIY AR lower project
    « Reply #2 on: September 08, 2013, 03:54:55 am »
    Hard to put a number on this project...I have a deal with a customer which includes use of their CNC equipment. I spent a lot of hours on the programming for the parts, plus mostly used my own cutting tools. Disregarding the cost of the milling machine and the time spent programming, I have about 200 bucks in the tooling and aluminum stock to make 3 or 4 lowers.

    If you wanted to buy a small CNC mill that can run on a bench (and could do this kind of work), you'd probably be looking at about $3-5K to get started. You can also find much larger machines in this price range, but you will need a way to rig and move them, plus a shop with enough room and 3-phase power. Such machines will probably need repair, plus you would need to buy tooling (not cheap) to do any work with them.

    Machine shops charge an average of $100/hr. The design I am building has six different parts (besides the standard AR lower parts kit). Most of them are milled, but there is a small amount of lathe work as well. If you took this design to Joe Smith's Machine and Tool, I would not be surprised to see a quote of $1000-$1500 to build a single one-off lower...assuming they would do the work for you. Making a firearm is only legal if you do it yourself or if you have a manufacturer's FFL. If Joe Smith builds one FOR you, they can find themselves in deep s**t very quickly.

    You mentioned milling one yourself...what equipment do you have? I cheated because I have a CNC milling center at my disposal, but this could be done with patience, planning, and skill on a manual mill...preferably one with a digital read-out. 
    "Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

    Adskii

    • Senior Member
    • ***
    • Posts: 843

    • Offline
    Re: DIY AR lower project
    « Reply #3 on: September 09, 2013, 06:17:54 pm »
    A couple of hacksaws, a file and some 18v tools... Not nearly enough to do something like this, but I may know someone who has the equipment that might let me have a crack at it. I know trying to get someone else to make it for me is illegal, and I wouldn't want to put anyone in that position. o i either need to find a REALLY cheap rifle or kit, or learn to do it myself.

    JesseL

    • Gun Mangler
    • WTA Staff
    • Senior Contributor
    • *****
    • Posts: 12451

    • Offline
    Re: DIY AR lower project
    « Reply #4 on: September 09, 2013, 06:21:48 pm »
    this could be done with patience, planning, and skill on a manual mill...preferably one with a digital read-out. 

    Manual mill with a digital readout: ✔
    Skill: ✔
    Planning: ✔
    Patience:  :doh
    Arizona

    Cookie

    • Member
    • **
    • Posts: 335

    • Offline
    Re: DIY AR lower project
    « Reply #5 on: September 09, 2013, 06:23:02 pm »
    If you can find a hammer and a dremel, you're all tooled up to do an AK  :cool
    "Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

    JesseL

    • Gun Mangler
    • WTA Staff
    • Senior Contributor
    • *****
    • Posts: 12451

    • Offline
    Re: DIY AR lower project
    « Reply #6 on: September 09, 2013, 06:28:11 pm »
    If you can find a hammer and a dremel, you're all tooled up to do an AK  :cool

    I found an air hammer and modified bolt cutters invaluable.
    Arizona

    Cookie

    • Member
    • **
    • Posts: 335

    • Offline
    Re: DIY AR lower project
    « Reply #7 on: September 09, 2013, 06:29:50 pm »
    Jesse, it might not actually be that bad on your mill...the pockets can all be done in straight lines with a 3/8 endmill and the radii will match the print. I was about to give it a go on my Bridgeport but I landed in a pile of free CNC time. The left half would be harder on a manual but I think it could be done.
    "Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

    Cookie

    • Member
    • **
    • Posts: 335

    • Offline
    Re: DIY AR lower project
    « Reply #8 on: September 09, 2013, 06:38:05 pm »
    I found an air hammer and modified bolt cutters invaluable.

    Once this and the .50 project are done, I will be milling up some AK trunnions designed for screw assembly...be interesting to see how they work.
    "Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

    JesseL

    • Gun Mangler
    • WTA Staff
    • Senior Contributor
    • *****
    • Posts: 12451

    • Offline
    Re: DIY AR lower project
    « Reply #9 on: September 09, 2013, 06:50:10 pm »
    Once this and the .50 project are done, I will be milling up some AK trunnions designed for screw assembly...be interesting to see how they work.

    Ooh, I'll enjoy seeing that.
    Arizona

    Cookie

    • Member
    • **
    • Posts: 335

    • Offline
    Re: DIY AR lower project
    « Reply #10 on: September 17, 2013, 07:25:09 pm »
    Just a couple pictures of the mill making chips. I'll be starting on the other half sometime this week.



    "Bushido is all very well in its way, but it is no match for a 30-06." - Col. Jeff Cooper

    Help support WeTheArmed.com by visiting our sponsors.