AMD 63 & 65 Builds on a Laser-Cut Flat

Intro:

I have been collecting info from several build sites for quite a while. I finally got all my questions answered and decided to just go for it and give it a try. So, I have just finished an AMD-63 and an AMD-65 screw build using a laser cut receiver from AR15plus.com. This receiver was so easy to build with! Both projects were a lot of fun and came out great.

Since I got so much help from these forums, I felt like I should give back. Is anyone interested if I write up a step by step of the build? I took a few pictures to include.

Step 1:
I didn't want to buy or build a flat press, so I thought I would try these laser cut flats. They are sturdy at .063" thickness. They come in a package with US made rails from AR15plus.com for $38.95.

They are very easy to bend (no press needed). The seams are cut nearly the entire length of the flat but small tabs hold the bend so that it stays in place until welded.

Simply clamp it into a vise sandwiched between 2 pieces of hardwood and bend it over by hand. Do the narrow top rails first.

The tabs hold the fold in place. You can use a rubber mallet to tighten the bend with a few taps, if needed.

After the edges are done. Clamp the middle cuts one at a time and bend them.

It will look like this:

Bent receiver:

Bent receiver end view:

Step 2:

Now it is time to weld the edges so that they are permanent. That is the trade off with this receiver flat. You don't need a press tool, but you need to have access to a welder. I have a Lincoln SP135, so I simply set the controls for heat and wire feed speed based on a .63" thick steel using the charts on the side of the welder. It worked great.

I have found that it is better to only weld the top rails first, leaving the bottom edges alone until after the trunnion and tang are both mounted. This will ensure that the final dimensions of the bend fit perfectly to them.

After welding and grinding/filing it will look like this. If you are a good welder (I am not) it will make everything easier.

Step3:
Now, you can attach the trunnion and tang and then weld the bottom edge to make it permanent.

I don't really need to repeat the steps to the rest of the build, as I simply followed the screw build that is described in other places like the AR15.com BIY Forums or my AMD pistol build writeup.

I heat treated the rail ejector and the receiver holes to increase durability . Then I used a wire wheel on a bench grinder and a random orbital sander to buff the finish. Finally, I used a spray-on baked finish from Brownells for the final finish. This stuff really runs, so I had to take it easy and put on thin coats. You will notice the runs in the first picture (had to redo that one), but I figured it out eventually. After it dries, hang it in the oven from a small wire and bake it at 315 deg for an hour or so and it comes out a hard, enamel finish.

More of the receiver:

Final assembly!

I put the muzzle brake from the AMD-65 on the AMD-63 and welded an extended brake from TAPCO onto the 65, making it legal length. I also ordered AMD mags and slings (not shown) from Tapco to make it look more original. The AMD mags are only 20rds instead of 30, probably because of the close proximity to the front grip when inserting them.

Q and A
1) Build costs: (these don't mean much as the prices are changing constantly)

$80 AMD-65 parts kit - centerfire systems or clearviewinvest.com
$39 laser cut receiver & rails - nationalordnance.com /ar15plus.com
$15 screw set - marshhawkarms/ak-47.org ($30 for 2 sets)
$30 7 US parts - Century Arms (min order $75)
$20 extended muzzle break - Tapco

$20 bake on spray - Brownells Gun-Kote (good for a lot of receivers)
plus 3 drill/tap sets from HD @ $4 each..

2) Taps
I had a set of taps from HF, but they are too soft. At Home Depot you can buy a card that contains one tap and one drill bit. I got one for 6-32, 8-32, & 10-32. They are only about $3.50 each (I think). I bought 2 of the 10-32 taps, and ground one down a bit to bottom tap the 4 front trunnion holes (2 per side). I started the threading with the pointed tap and then extended it with the bottom tap.


3) Heat Treating info
I ordered an info packet from Marshhawkarms and also read some other sources that described the process. Basically:
(a) Using a MAPP torch, heat the metal until it is RED in color then quickly dip it in water or oil to cool it (I bought a bottle of MAPP at HD). Since this makes the metal hard (60C Rockwell) but too brittle, you need to temper the metal....so:
(b) re-heat the metal to a BLUE color and then let it AIR COOL. If it gets red, cool it as in (1), and re-do the tempering.


3) Center Support
The part is called an aluminum binding post. They are 8-32 x 1 1/4". I went to a hardware store looking for parts for several different solutions that people had mentioned could be used to make a cross member. I found this part and it just happened to be the right length and diameter and very close to the other 2 pins' dimensions. Also, it required no drilling or tapping, since one side screws off. It looks like the pins used to hold the old scrap-books together. The only drawback is that it is soft. However, you can find steel ones.

Here is a place to get them ScrewPosts.com

See more about this in a later post.
Other options are:
a) buy a 5/16" O.D. steel rod and drill both ends for rivets or tap both ends for screws (10-32) like here and here

One Quote from a post:
"Just buy a 5/16 half threaded bolt, cut a piece without threads to length (1.182" works for me), rifle drill and tap it for 10x32. Easy as 1 2 3. Or, just spend a couple of bucks and buy a center support bushing and rivet from K-Var or Global Trades."

b) buy rivets like here or here

c) buy a long 10-32 bolt, cut it to size and put a nut on the inside and outside of the receiver.

d) Weld in a pin or bolt.