Does anyone have any tips on the best way to do this?

I am no expert but I have done two now and both work....

The way I did mine was to simply get the front and rear trunion areas of the receiver cut out first so that the receiver alignes with the trunions.  I used a dremmel to get it close and then used metal working files for the final fitting as a file is much easier to manage.

After the trigger guard is riveted, the front trunion is installed and riveted, ane the barrel is pressed in you then need to be able to get the bolt carrier to slide enough to check the headspace...  I use a dremel to get the upper rails wide enough for this check.  After you are happy with the headspace and the barrel pin is reinstalled check the headspace again...

Then install the lower rails and make sure you have no problems with the bolt/carrier again!

Then install the rear trunion.

When the front and rear trunions are installed you will discover that the upper rails are too close together for the carrier to work.  I simply used a dremel to get the rough size needed to drop the carrier into the receiver and to allow the carrier to side the length of the receiver.  I then finished the process with my metal files to clean up the cuts in order to get a much better looking job.

Just remember to make sure that your openings are in the center of the receiver (keep the carrier centered) and take your time...  A bench grinder is faster but risky... a dremmel is quick but can screw up a receiver if you are not careful, a set of metal files are pretty darned safe as long as you are thinking about what you are doing while you are working...

Hope this helps some...

Quarterbore's way will work but it is labor intensive and repetitive IMO.

I fold the receiver, weld the rails in, install center support, then 'dry run' the BC.  Since the trunions aren't in place yet, the ends of the receiver will bow out a little.  No worry, this gets you in the ballpark.  Dremel away to get the BC moving.  Put the trunions in and trim some more.

Don't over complicate the process.  It's an AK and has a lot of slop built into the design.

I'm working on a way to use an end mill in my drill press.....

Quoted: Quarterbore's way will work but it is labor intensive and repetitive IMO. I fold the receiver, weld the rails in, install center support, then 'dry run' the BC.  Since the trunions aren't in place yet, the ends of the receiver will bow out a little.  No worry, this gets you in the ballpark.  Dremel away to get the BC moving.  Put the trunions in and trim some more. Don't over complicate the process.  It's an AK and has a lot of slop built into the design. I'm working on a way to use an end mill in my drill press.....

The video that Curt at AK-Builder.com put together shows him doing this on a milling machine...  the latteral forces on the endmill wouldn't be that much so I bet you could do this on a drill press or one of the small router tables they make for rotary tools....

Yea, no contest as well that my way does take time but it is easier to make sure you don't screw something up with removing too much metal as by the time you are fitting the top rails you already have quite a bit of time invested in the build.

I don't have pics of this part of the build yet but when I find the time to do my next build I will document this part better....

I think I saw a tutorial somewhere where someone used a dremel with a router attachment that allowed him to control the 'depth' of the cut.  Sounds interesting also-

ETA:  When there's several/many ways to do something, it usually means that there's not one clear winner or best way- they all suck in certain ways......

When I cut my top rails I like to take a piece of 1.25-inch wide falt stock steel and clamp it in there... that helps prevent damage to ther parts of the receiver (lower rails for example).

Does anyone have the width specs for the top rails at:

1. The trunnions
2. Bolt installation slots
3. full width

The Dremel w/router attachment is an interesting idea, think I'll look into that.

I was thinking about using JBWeld or other epoxy to attach large washer to the shank of a mandrel for the Dremel fiber cut-off wheels. The washer would rest against the outside wall of the receiver to maintain a contstant width for cutting the rails. I was thinking about making 2 different sizes, one for cutting the trunnion areas, one for trimming the overall rail width.
It would probably be best to do this on a receiver flat build just after bending and prior to the installation of the lower rails and trunnions.

I cut my receiver to match my parts... I never measure anything!

Quoted: I cut my receiver to match my parts... I never measure anything!

me too.  

J