Well, taps and dies are cutting tools, so... what the hell...
I'm interested in cutting threads into wood at a diameter of about 2.5 inches at about 4 TPI. The problems: a tap and die set for wood in this size costs around $1,300. Once I get a functioning tap, I can then make a die from wood and some HSS for cutters. So, the die... A die for metal of about the right size and pitch (M64x6) is only slightly cheaper than the wood tap and die set. Taps can be made from bolts by way of an angle grinder, but going that route would put me back around $500 to $700 for a single bolt. I'm really not up to making a tap of the sort that resembles a gunsmithing jig for cutting rifling. So, what else is there?
These large screws are generally cut threads ( like with a router) and not done with a tap box. 2 1/2 inches of diameter and a 3 TPI thread is sort of typical for a woodworking bench.
In the old days, they were generally 90 degree triangular threads instead of the 60 degree threads you often see in drill rod, etc. That said, i bought a professionally made screw with a modified pattern - 60 degree threads, but flat topped so that when a woodworker drops something out of their vise, it doesn't just break the tips of the threads off. It works very well.
I haven't used a tap of that type bigger than 1 1/2", but I have taps of that size that are chinese and for all of the griping that you can find about them, their only real flaw is that they're not sharp when delivered, and that all are 6 tpi.
But for really big threads like that, I would use some kind of jig and a router bit that's fresh and sharp so that they're cut cleanly, and design something to turn the dowel - even if it means buying a length of threaded wood that's usable to advance your blank.
Historically, really large threads were often sawn or carved, or sawn and then cleaned up. I'm guessing they were done that way instead of with a giant tap box because there is less breaking out and as long as you can mark them reasonably well, you can cut well - but that assumes the maker does have the hand skill to cut accurately or carve accurately. this would've been a common skill 200 years ago, but not so common now.
Sorry I don't have a better picture of the bench and screw, but you can see where the screw resides within this vise. I was worried about strength, but I was wrong about that - the holding strength is nothing less than spectacular and the thread pitch (3) makes it usable without any other gadgetry - as in not that many turns to open or close what you're working on.
once you have the threaded rod, you could segment a piece of it, taper it and install progressive cutters to cut a holding nut or threads in whatever you make. there needs to be some room for movement as it's wood and it does move seasonally and will seize when it's humid if it's too tight.
