Ive read through all the posts i could find on this here and I still have some more questions before i jump in.  Is it possible or maybe i should say an ok practice to try to rivet the trunion with the barrel attached.  I see that taking the barrel off would be much easier as far as pressing the rivets in but i dont have a press or a set of headspace gauges.   I have seen the threaded rod idea and that looks interesting and i may could use that but then i have the problem of getting the barrel off to begin with.  To press the rivets i was going to use the bolt cutter idea i saw on here.  Thanks for the tips on that and the threaded rod BTW.  Its just that i have limited tools and live in an apartment so that really makes things complicated.  Are the rivets somethinmg i can maybe find locally or am i pretty limited to kits as far a avaliability? I was origionally going to do this with screws but after reading i think i may try to go with rivets now that i found the bolt cutter tool.  Another thing that kind of has me curious is what is accually holding the barrel in place on an ak.  Is it basically just the press fit or is there something im missing?    Thanks for any help I just figured id ask some questions before i messed up my project.  Major    

There's a pin pressed into the trunion that holds the barrel in place.  That pin is placed after the rifle is headspaced, so taking the barrel out of a kit isnt really a concern in that department.  go Here and read all about what you need to do to build from a parts kit.  There are alternate methods for pulling barrels like using pullers and using the hot-cold method for reinstalling barrels.  

It is possible to rivet with the barrel still in.  I think the problem with that is, if your rivet runs off to the side, you'll have a heck of a time getting it out.  Also, you have to drill out the rivets, which means you have a chance of drilling into your barrel.

There are a few people on the EE selling rivet sets.  Global Trades and KVAR also have some Eastern European rivet sets for sale.

I just finished deconstructing two Romy kits One barrel pin was a little bit stubborn but it came out.  The other was a piece of cake.  Couple of whacks with a hammer and drift pin and out it came.  I used a rivet setting tool (available at leaather working stores) to remove the barrel. I have a vise that I had bought from Brownell's that can be placed on it's side.  I put the barrel with the remains of the receiver in the vise. Then using some pennys as a buffer, I drive out the barrel using the tool.  Works extremely well.  I don't have a press and have no intention of buying one.  One thing that I do is soak the pins and the barrel shank in Kroil.  It's a super penetrating oil and makes the removal of the pins a lot easier.
I tried the vise to remove the pin but that didn't work.  I think that the sudden shock of the hammer blow breaks the tension of the pin to the barrel.  Once that happens the pin will come out easily.
So far I have taken apart 3 Romy kits and haven't experienced the pin from hell ordeal.   I think that the secret to barrel pin removal is the application of Kroil or something similar.  After removing the barrel , I could see a nice film of oil on the barrel shank and trunnion, so the Kroil did it's job.  I only used a 22oz. claw hammer(I'm a carpenter) to drive out the barrel.  I had a 4lb. mini sledge if the barrel got persnickety but I didn't need it.  Lubrication is a wonderful thing.

Quoted: Lubrication is a wonderful thing.

M98.  I will probably get flamed for saying this, but if you do your homework, proceed cautiously, and have a good mechanical aptitude, you can do this with very few tools in an apartment.  But it will be tedious, and you will run the risk of damaging your kit and possibly some body parts.   I have a full machine shop, but just for grins, I built a Romanian using nothing more than a hammer, a drill press and a Dremel tool.  I could have gotten by without the drill press.  I did not pull the barrel.  (This means that little donuts of the rivet tails are left in the trunnion rivet cavity.)  I used tinner’s rivets available at most hardware stores.  These rivets are softer than specification rivets and have a flat head.  It is odd, but they come in the perfect sizes.  IMO. the gun is safe and looks alright.  Having said all that, my advice is to make friends with someone who has a shop, and do it right.  

As a minimum, you will need:

Lots of homework
Romanian kit
Hammer
1/4” pin punch (or a bolt) for pounding rivets
Something solid to pound against (such as a concrete floor and a piece of steel).
Dremel tool to get the old rivets out and trim/drill the receiver
100% receiver
US compliance parts at your discretion
Tent, rocks, camel dung and a fire (just kidding)
Something else I probably forgot

One of these days I may write a tutorial on bare bones construction, but for now, I am quite busy (aren’t we all).  So please don’t ask, OK?

I think ill try this just to see how it goes.  ill try to snap some pictures od the build so other people in my place will knowit can be done and what can be used.  Thanks for the info.  Major