I've some experience with building an AK from a parts kit. (See Building an AK, Part 1 and Part 2). I have friends that are also partial to the AK, and I have been helping one of my friends recently with a parts kit he had purchased. Because he wanted to build one by riveting rather than using a screw build, as I had done, it was substantially more complicated. However, I left the riveting to him.
For the riveting, he bought a set of bolt cutters from Harbor Freight, and replacement jaws. The modified bolt cutters are actually only good for the short rivets on the front and rear trunnion. I insisted he do this part himself for several reasons: (a) so he would have the experience, (b) because they were his tools, and (c) it was his receiver.
He purchased a special riveting tool and buck bar set for the remaining rivets, including the long rivet in the rear trunnion. These latter tools require a shop press to squeeze the rivets. And of course, the installation of the barrel and various pins require the use of a shop press.
This is where I come in. Not only do I have the experience with seating barrels and pins, but I have the press to do the job. We had pressed the barrel and set the head space on a prior weekend, which I have to say was not as easy as when I worked on my own kit. For some reason, not only did I have trouble getting the barrel aligned, but I had problems with the seating--I seemed to just push it bit too far, or just be just a bit short, at various times. I think I fully removed and reset the barrel at least a half-dozen times. It was made somewhat more difficult because of the order of assembly. With a screw build, I was able to seat the barrel in the front trunnion, then attach the trunnion to the receiver. In this case, because of the riveting, the trunnion has to be installed first, and then the barrel pressed in. This takes a special support piece to hold the receiver/trunnion in place, which my friend had also purchased. My friend had also purchased go/no-go gauges. I don't know if they worked better than my "work around," but they were probably safer.
This weekend we finished with cutting the slot for the barrel pin and pressing the pin, cutting the slot for the pin holding the sight block and pressing that pin, and, finally, crushing the long rivet in the rear trunnion. I has asked him to do the rough cutting on the slots, and then I finished them off--doing a bit more cutting and filing the slots smooth. I used a finer oil this time to lubricate the pins, which seemed to help (I used a cutting oil I had bought from Midway).
All in all, it's been fun building another AK. Unless you are going to use a screw build, or build several AKs from kits, it is not cost-effective to build your own. If you are going to build your own, it should be because you want the experience and challenge.