Thinking about 80% AR-15 receiver


May 15, 2006, 01:30 AM
I'm looking into buying one of the 80% finished AR receivers and wondered if anyone had any advice. I'm looking right now at kits from KTO and

I'm looking for any tips or advice about either of these kits or links to others that you'd recommend.

With the jigs each of these comes with, can I get away with just using my hand drill and Dremel or is it necessary to get access to a drill press (or use this as an excuse to get one)?

How about finishing? I'd like a nice flat black that will last.

What else am I not thinking of?

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May 15, 2006, 12:15 PM

Brian Williams
May 15, 2006, 12:41 PM
Drill Press or Milling machine, loose the Dremel and put away the hand drill, Actually take the Dremel out to your driveway and run it over with a truck or tank preferred, if you do not have a tank, use the largest gun you have on the Dremel. Repeat after me, Guns are for Dremels, Ok :)

To make a 80% right you need some good machines and the right tools, particularly the right tap for the buffer tube and the right drills and reamers for the trigger and hammer pivot holes, actuallly for all of the holes.

May 15, 2006, 04:00 PM
Thanks for the replies. I'm going to hang onto my Dremel. I have a few more uses for it than rifle building.

The kits I've been looking at come with all the necessary bits, taps, and reamers, so that seems to be covered.

I guess, even with the jig, you still run into the problem of 90-degree drilling. So, if I use a drill press, the jig will be there to put the holes in the right place and to hold the receiver perfectly perpendicular. Does that sound about right?

I've always though anodizing just produced a gloss finish. Thanks for suggesting that. I'll look into it. Anyone have any thoughts or tips for that?

AZ Jeff
May 15, 2006, 04:40 PM
There are different types of anodizing that can be done to aluminum parts. Decorative anodizing creates a satin finish, generall, but can be adjusted to create a high gloss finish, too. Such decorative anodizing can be done in a variety of colors.

"Industrial" anodizing, more correctly called "hard-coat" anodizing, is what is employed on the military AR-15/M-16 rifles. It's generally a dark gray color, but most importantly, it's thick, and creates a very hard outer layer on the aluminum, in excess of Rc 50.

May 15, 2006, 06:40 PM
If this helps, M16 receivers are cut on CNC machines fixtured to four side tombstone pallets holding 24 lowers minimum, six to a side.

You can do all the work on a conventional mill and may be able to do most of the work on a radial arm drill press.
A standard drill press will not be stable enough nor will it be fast enough in rpm and feed rate to properly cut the aluminum.

Avoid the 80% receivers unless you are lucky enough to have a Bridgeport knee mill, or better yet, a HAAS or Cincinatti CNC machine sitting in your workshop.

May 15, 2006, 09:04 PM
I've heard they can be finished easily with just basic hand tools. Good luck with your sounds like a fun project.

May 16, 2006, 12:10 AM
Sounds like a challenge...

May 16, 2006, 09:14 AM
I don't know all the specifics involved here, but can give some general advice. I've managed to do alot of pretty intricate/difficult things (for example porting a barrel) with my $75 benchtop drill press from Harbor Freight. But, I have a slight advantage, in that my dad was a machinist, and I started playing with all kinds of fancy stuff when I was about 9. Key is being able lock down the work piece VERY securely.

Any way, I have 2 words of advise if you're gonna be working with aluminum:


Helps when you're drilling, but is ESSENTIAL when tapping. There's special oil available, but even some WD-40 will help. Turn the tap no more than one turn or so, then back up to clear it. You have no idea how many taps I've broken off in aluminum parts, even though I know how I should do it (I usually just get in a hurry). And removing a broken tap, without damaging the workpiece is a b**ch!

This is even more important with cheaper taps (and I suspect the ones included aren't all that good) than better ones. the cheaper ones will work, but are more brittle, and break more easily.

May 16, 2006, 09:56 AM
You want a gun tap. That's where I see a lot of people run into problems.

Not gun tap as in one meant to tap holes in guns - They're designed to be used in screw guns. Hand taps generally have four flutes (smaller ones have three) but gun taps have just two, and they have a way beefier cross section.

We use them in the panel shop here at work to tap the zillion fiddly little holes we have to thread out on the back plates for panels. We use 'em on steel, aluminum, and even stainless in drill presses and with hand held drills. Dulled a few, but I ain't broke one yet.

May 16, 2006, 11:59 PM
I only looked into these really quick, but the value of them comapred to a complete upper didn't seem, worth it to me. If it's the chalenge you seek, well then never mind this reply.

May 17, 2006, 12:32 AM
A friend of mine made one with a hand held drill - AFAIK, it's still working just fine.

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