DIY AR-15 Lower Receiver tutorial
VaderSpade posted a very nifty tutorial on how to machine a AR-15 lower receiver.
You won't save money making your own. You need a mill machine, which second hand will cost about $900, and Tactical Machining's 80% Master Kit jig which sells for $410.
[ Many thanks to jdun1911 for emailing me the link. ]

While it’s true you can’t sell the recievers, you can teach those interested and charge for the instruction / use of equipment. Once you recover the investment you’ve got yours for free. and you will be an expert in the process.
You don’t need the $410 kit.
For this project the $150 kit will do.
Or order the same kit with an 80% lower for $195
Now that’s a deal!
And you can do all this on a chinese minimill just as well
you won’t make any money if you only make one…
John, I don’t think you are allowed to make them for sale. The BATFE would not like that!
$410 is for both the ar-15 AND ar-10 kits.
If you just want to make an ar-15 it’s only $195.
Still not very cost effective unless you’re doing huge batches but then again saving money really isn’t the point.