I built a pin press yesterday. The cost was $17 for an 8 ton bottle jack from Wal-Mart. The rest of the materials I had laying around. I used a U channel piece of metal for the top and bottom plates. Square pipe (1"1/2" I think) for the pillers with threaded rod through the square pipe connecting the top and bottom plates.
here you can see the threaded rod in place and a square pipe standing in place.
this shows it all bolted together. I pumped it up just bolted together and it held. I welded the whole thing up anyway since I like to weld. If you don't weld, it would be a 15 minute job at your local weldor so it wouldn't be that much.
I made 'points' out of 01 rod I had. I heat treated them with a torch to get them hard. I also mounted an extra piece 1/4" plate to the top part of the press to spread out the pressure a bit.
Here it is pretty much done. I knew this would be 'tippy' to the front from the start as the base was narrow. I figured I'd bolt it to a board or clamp it in my vise to use. I ended up welding some angle iron to the front of it (not shown here) to keep it from falling over when pumping it.
There are a few more pictures of the process at this link...
http://www.mickleyknives.com/html/pa...pin_press.html