build yer own lower

Record cold and snow in MN. I'll soon be locked in the shop for the duration of winter and been casting about for a worthy project.
I came accross this: http://www.dsarms.com/prodinfo.asp?number 01
Is this a good forging to start with? Anybody else done this? Any heads up for problems? Any fixturing suggestions? I'll plan on building quality fixtures to knock 'em out on the CNC mill.
Karl
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On 12/27/2010 7:55 AM, Karl Townsend wrote:

Drawing and machining a prototype lower was one of the first major projects I had in Solidworks. I've always wanted to go back and redraw it because I know there are better ways to get-er-done now. We started out with a solid block of material. iirc it was at least 12 ops to get it all done. Well, almost all done.. had to leave a couple holes out since the ATF wasn't here to serialize it.
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On 12/27/2010 8:16 AM, tnik wrote:

Here's a pic of the model..
http://picasaweb.google.com/KortJester/Work#5555354623707171330
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On 12/27/2010 7:16 AM, tnik wrote:

Any special reason you left the bottom of the mag well parallel to the top? Some current mags wouldn't fit.
ATF doesn't need to serialize it nor do you if you're building it for your own use. You can't sell, give away or otherwise transfer it unless you have a manufacturer's license, which is when the serial number becomes necessary, which the manufacturer does, not the ATF.
David
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On 12/27/2010 11:34 AM, David R. Birch wrote:

That was the way the customer wanted it. I had to reverse engineer one that he brought us. I was lucky enough to find a dxf of an AR-15 so I could get the proper hole placements and tolerances.

Exactly, this was an actual job we were looking at getting so if we went into production of the parts (iirc) an ATF agent (or someone that could do it) would have needed to be present during the final operation and serialization.
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So what happens when you die?
Wes
--

Beware speaking with a sharp tongue as you are apt to cut your own throat.

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Wes wrote:

Whoever inherits it needs to do the paperwork for an NFA firearm. Remember this applies to NFA firearms, not to "ordinary" firearms.
The paperwork is confusing since it generically refers to "firearm" in the title, however further into the forms they specifically refer to NFA firearms only. Look at ATF form 1 which is titled "Application to Make and Register a Firearm", but further down on the instruction page it specifically refers to NFA firearms only. It also has "Estate Procedures: For procedures regarding the transfer of firearms in an estate resulting from the death of the registrant identified in item 3, the executor should contact the NFA Branch, Bureau of the ATF...". You can download the forms from the BATFE site.
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Bzzt-WRONG ANSWER. It is NOT an NFA firearm unless it's full-auto or shorter than legal length(26") or has a short barrel(<16" for a rifle). Full-auto creation is prohibited as of 1986 for mere mortals, you have to have the special ATF permit to do that or you go to jail, do not pass go. No new full-autos for civilians. You CAN sell your semi-auto creation, just don't make a habit of it. ATF regs are fuzzy in this area, if they recover a number of home-made guns that can be traced back to you, you WILL stand a good chance of seeing the inside of the crossbar hotel. If it's sold, you should put a name and a serial on the thing, ATF has the requirements for marking on their website as far as depth and size of lettering. State and local laws vary, but federally, it's legal to make your own pistol, rifle or shotgun with no other paperwork. ATF doesn't even have to know about it.
As far as the OP's desire to make an AR lower, knock yourself out. You'll find that the tooling cost will go a long ways towards a completed gun, so it's not really cost effective. I've seen lowers as cheap as $60, stripped. A tap for the buffer tube will run at least $100. Then you get the fun of trying to chop out a close fit on the mag well without a broach. The only thing you gain by doing it yourself is the experience and an off-paper lower. What's your time worth?
Stan
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I know exactly what my time is worth. the only job I've collected a salary for in the last 25 years is Township Supervisor. It pays $600 a year and I put in 150 hours to collect it. So $4 an hour is about right.
I remember talking to another fella in my business. He said,"I don't mind the minimum wage but i do wish I could earn that much"
Seriously, the goal here is to do something to be proud of this winter. AND, do it in the heated shop.
Karl
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wrote:

Here's a project that'll keep you going all winter: http://www.gatlingguns.net /
Stan
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On 12/28/2010 8:43 AM, Pete C. wrote:

I must have missed the message that changed the issue from manufacturing a receiver to making an NFA weapon. AFAIK, you can't make an NFA weapon for your own use as of 1986.
David
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"David R. Birch" wrote:

Early on the thread discussed the legality of making your own AR lower. There was a lot of confusion about restrictions with people confusing NFA only restrictions as applying to non NFA firearms.
You also seem to be confused about NFA firearms, as the 1986 date you refer to only applies to full-auto machine guns, and not to other NFA firearms like short barreled rifles, silencers, etc.
I'm vaguely kicking around the idea of sending in the paperwork and $200 to get a tax stamp and paperwork to legally build a silencer, but I'm not sure if I have enough ambition to do all the paperwork.
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On 12/28/2010 5:39 PM, Pete C. wrote:

Yes, my statement was overly broad, but I meant it in the context of the discussion which was about AR-15 lower receivers.

As I understand it, a short barrel rifle with a suppressor requires only one tax stamp. I've been kicking around the idea of something like a deLisle carbine based on a '93 Mauser action.
David
David
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Karl, just curious what are you trying to accomplish, build a particularly accurate or otherwise high performing rifle, or just make something that is legal and does not require a 4473?
i
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No particular reason. I just need a challenge. Saying, "I made it myself" gives a bit of pride. certainly not doing this to save $.
Karl
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Karl, I wanted to ask a question about manufacturing methods for the Ar-15 receiver.
Look at this:
http://www.cncguns.com/projects/ar15lower.html
He had to reclamp his piece numerous times to make it on a CNC mill. I wonder, how much of that is due to lack of the 4th axis.
My feeling on this is that with a suitable 4th axis, this receiver could be done in 2-3 reclampings, or perhaps even one. With a 4th axis, clamp once, and then turn various sides towards the spindle to be machined.
Am I making any sense?
i
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On Tue, 28 Dec 2010 00:04:37 -0600, Ignoramus7943

I had not seen this site, thanks.
You have a valid point, but you lose so much rigidity that your machining speeds would be killed.
Most parts are manufactured with a real eye on fixturing. That is ways to quickly remount the part for the next operation. With a good fixture design, you can go from one op to the next in a few seconds.
I had not seen this website, thanks for the link.
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Well, yes, but when I am making a one off receiver, I do not care as much about machining time, as about how much time would it take me to make one off fixtures, reclamp everything, touch off the tools, align etc.
So, if it would take me 5 hours of machining time to make a receiver, but only one personal hour, it is a better deal than 30 minutes of machining, but 3 hours of making custom fixtures and clamping and reclamping and dealing with mistakes.
Anyway, I admire your plan and am looking forward to seeing how you make that receiver. I am getting an itch to make something like that as well.
i Not speaking from any actual knowledge, of course.
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Karl Townsend wrote:

Production fixtures would probably use hydraulic clamping, and be able to flip the part around and reclamp in a matter of seconds and/or use palletized fixtures holding a number of the parts at a time for quick changes in the machine and off-line reclamping.
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wrote:

For the low volume us HSM types do, you can't beat 1/2" socket head cap screws holding a part in a custom pocket. Use an impact wrench to change parts in a few seconds. Often one screw will do. Two will hold dang near anything. Another great device is a toggle clamp
Karl
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