Along with Anvils, power hammers, and companionship, A good blacksmiths vice is one of those things you usually just have to buy. thus, it is one of the most satisfying things to make for yourself, right up there with junkyard hammers and android girlfriends.
Now, I personally have made the proper sacrifices, and thus been blessed by the vice god, having in my possession a magnificent 70 lb bench vice that's been in my family for 3 generations. but still, it's not a proper blacksmiths vice. A blacksmiths vice (AKA, a leg or post vice) is much more solid due to the leg, and just generally better suited to metalwork.
Before we go any farther, I should warn you that this is not a super-duper in depth instructible; primarily on acount of my having made the vice before writing this down. Much as I like y'all, I'm not gonna' go back and make another one simply for the sake of pictorial accuracy. So, if you notice any discrepancy between what I do in the pictures, and what I tell you to do, do as I say, not as I do. The pictures are simply of my attempt to realize my naïve, if grand, vision; while the words hold wisdom born of experience.
Post scrip: I think it goes without saying, but this is a welders only thing. If you don't have a welder, get one. Trust me, it will be one of the more worthwhile purchases you will ever make.
Step 1: Materials:
To start with, you need a 30" and a 6" piece of 1" square bar-the main post.
A 3/4" hexagonal crowbar, or equivalent spring steel bar.
Two 6"x 3/4" square spring steel.(I used two squared off railroad spikes)
an 8" piece of 1" threaded rod or bolt, with a nut.(this will probably be the hardest thing to get, I found one next to the train tracks.)
Various pieces of steel you probably have lying around on the floor.
Step 2: Start Forging Things Into Shape.
Step 3: Start Welding Things Together
Step 4: Go Crazy in Regards to Aforementioned Welding.
The concept here is pretty simple, so I don't feel like I need to go in-depth into assembly. Just weld everything together in a way that makes logical sense. However, it is some very nasty (dare I say, gnarley?) welding. I was out there for about three solid hours just going over and over seams, adding reinforcements were I though it needed them. I probably burned through a good two pounds of rods.
Step 5: IMPORTANT.
Maybe this'll seem obvious to you, but it almost ruined my vice, so bare with me here. Se how in that first picture I've got a circular loop going around my bolt? Don't do that. turns out the bolt needs to be able to oscillate up and down as it's cranked in or out. Turns out you actually need more of a channel, as illustrated in the second picture. yes, it seems obvious in hindsight, but if someone had told me this, it would have saved me a lot of time cutting up welds.
Step 6: End Notes.
It's done! It worked! And it's pretty rad, yo. I took it out and strapped it to my special forging log, and it works perfectly. I've used it for upsetting, twisting, you know, all that good vice stuff. I will say, it doesn't grip quite as tightly as, you know, a professional vice. But for the price,(basically free) and the fairly low amount of time, I'd say it was well worth the effort.
Now would I ever make another one? No. not unless someone paid me a decent amount of money. The bars were just entirely too large for the forging to be pleasant, and it was a bit too much welding for my liking. But the important thing is that I proved that it is possible with no prior experience, so what's your excuse? go and make yourself a vice.