http://www.gunsnet.net/showthread.php/14530-Rivet-jigs?s=4cc60789b387f72a3a0a2adbe38452c1&p=195857&viewfull=1#post195857

Better explanation of my plan. Still unsure if a hammer is a viable substitute for a press. Guess there's only one way to find out!

I broke down and bought the bolt cutter and rivet crusher jaws. I'm trying not to get the cops called on a noise violation so I want to minimize the amount of pounding I'm doing. Plus I recently relearned the value of having the proper tools in an unrelated project. For anyone remotely interested, here is a list of all the tools that are going into this project:

For receiver work:
5/32 cobalt bit (rivets)
17/64 cobalt bit for swell neck rivets and to dimple my "rivet punch"
11/64 cobalt bit (rear trunnion long rivet)
3mm cobalt bit (front sight pins)
7mm HSS reamer (barrel pin)
1/4" HSS endmill (barrel pin)
Dremel (I got a $20 WEN from Amazon; make sure you get one with grinding discs and diamond tipped bits grinding bits)
Dremel carbon steel polishing brush (I bought this for surface prep. Do not buy it. It didn't even mar the paint on my old polish kit. Used Scotchbrite pads and had great success.)
Dremel tungsten carbide cutting attachment
Brass/Steel Punch Set
Steel center punch
General purpose metal file
DeWalt 20V cordless drill
Ball peen hammer
Bolt cutters
Bolt cutter rivet jaws
7" aluminum circle 1" thick for use as an anvil
1/2" diameter steel round bar (rivet punch for long rivet and trigger guard rivets)
A used vise from a milling machine off of eBay. Mine opens to 2 1/2", but I wish I'd bought one at least 3 1/2" because it's a PITA fitting shims to hold the receiver.

For "pressing" my barrel and attachments:
1/4"x20 thread 36in grade 8 steel threaded rod from McMaster-Carr, and a bag of grade 8 nuts to match
Aluminum washers
Length of 3/4" aluminum tube chopped into pieces
Kitchen freezer (chill barrel)
Oven (heat front trunnion)

For locking the stock (so I am California compliant with overall length):
3/4" copper pipe (short section available in plumbing section) cut to fit rear trunion and sliced in half
Hose clamp
This will prevent the button from disengaging the stock but is easily removed when I leave this vagina of a state

Cutting oil
Emery cloth
Dust mask (safety first!)
Hi temp black paint (500° engine enamel). I don't have the money, facilities, patience, or inclination to sandblast and parkerize this thing, and it was originally a painted kit anyway.
Masking tape
Aluminum duct tape (I used this to cover my bits when I was drilling into the barrel so that the bit didn't eat up the components)
Scrap wood from old DIY projects for leveling and clamping in the vise
White lithium grease (there are probably better lubricants but I had a giant tube on hand)
Front sight windage adjustment tool
Laser bore sight

Things I wish I'd had (space and money constraints):
Calipers
Drill press
A headspaced kit with barrel pin drilled

Pictures to follow when it's all done.

After many days of work hunched over on my cardboard-covered balcony (I only put maybe an hour a day into this), the receiver is drilled. Most of that time was spend opening up the holes for the underfolder stock.

I transferred hole positions from the trunnions to the receiver with masking tape, center punched all the holes, drilled pilot holes with my 3mm bit, then opened the holes with a 5/32" or 11/64" bit as appropriate. Had a couple improperly located holes, but more on that in the next post.

I drilled out the big holes for the stock with the 17/64 bit and the smaller holes to the side with 11/64, then finished them out with a dremel tungsten carbide cutting bit. It was a gigantic pain in the ass.

Lesson learned: If you're building a sidefolder or underfolder, spend a little extra to get a properly cut receiver.

In this picture, you can clearly see that I fucked up the right-side front trunnion holes. I drilled my pilot holes, and then instead of checking them against the trunnion, opened them up. Sooo you can see they were kind of off. The forward-most and rear-most are OK, as the rivets will fill in as they deform, but that middle hole ended up way too big.

I corrected from the original hole by inserting the trunnion and using it as a jig to drill through from the left hand side. I cut a small slice off a tootsie roll pop stick (same diameter as the rivet) and secured it in the hole in the proper position with masking tape, then applied JB Weld with a toothpick to fill in the gap. After the gun is finished you won't see any hint of the JB Weld.

After this fiasco I was more careful. Some of my pilot holes for the rear trunnion were off, but I figured out a pretty easy way to correct them. I inserted the rear trunnion and eyeballed which direction the hole needed to go. So let's say my pilot hole was left of where it needed to be; I would need to open it up to the right. I scratched the rough appropriate diameter into the receiver with my center punch. Now I had a small drilled hole located somewhere inside of a larger circle. Using the dremel and round diamond-tipped bit, I carefully ground down maybe 1/32" around the circle I had scratched in. This allowed me to center my 5/32" bit over the proper location, instead of in the off-center pilot hole. Doing it this way required only some minor finishing touches with the dremel cutting bit and no more JB Weld.

Tomorrow I plan to rivet the front trunnion to the receiver. After that I will press and pin the barrel, then populate the barrel and paint the whole mess before assembling the stock. I suspect the barrel will be the biggest pain in the ass of this entire experience.

So, a couple days behind schedule but I got around to the barrel today. This is my ghetto ass set up. I had 4 stacked zinc washers and they deformed and popped through the rear, so I slid the old bolt cutter jaws on to reinforce them.

In retrospect, I should have installed the barrel before touching the rear of the receiver...

So this is what happens when you try to put the barrel in using the receiver as your stop. I was able to bend it back into place with pliers, but now I know.

On a different note, the barrel is stuck hard about 1/4" from where it needs to be. I bend fucking grade 8 threaded rod trying to move it and it did not budge. No luck getting it to move back out either. I should have cleaned up the inside of the front trunnion with some emory cloth before I went to down but it looked good to me. Ordering another $90 worth of specialty tools to try and work it in. If this fails I'm going to abandon this particular project and sell what I've got on gunbroker, then save a few bucks for a headspaced kit.