At a recent garage sale I picked up a item that would hold a die and then be the chucked in a tailstock. It was meant to hold a round die. On the way home I realized the my dies are hex shaped. I can remove the inner piece that the die sits in and replace it with one that can hold my dies. So basically I need to have an OD that is round and an ID that is hex shaped. Doing the OD on a lathe should be easy. Problem is, how do you make a hex ID? I don't have anything that I can use for a punch.
I made such a beast using the business end of an appropriately sized 6 point socket. I machined a pocket in the holder and cut the end off the socket, faced it square and TIGed it in place. Looks like it was made from the solid.
Hex-shaped dies are normally rethreading dies, Wayne. You might want to look into buying a set of threading dies, I think they might work a lot better for you.
Further, in my set of rethreading dies (hex outside) the outside hex dimensions aren't constant across the whole set. So one hex insert wouldn't do ya.
Probably the easiest way to make this would be to make it in 2 parts and then weld it together. Carefully. You can stroke it using a shaper, or you can stroke an internal shape using a lathe or mill if you know how. You can cut a rough hole using a plasma cutter and then file to shape. You can chain drill and file. You can drill it and break a bandsaw blade and pass it through and reweld it and carefully saw the inside. You can drill it and pass through a saw blade you can use with your die filer if your die filer has the saw attachment. You can drill little holes in the corners and then bigger ones in the middle and then broach out the remainder using a hardened and ground hex wrench of the correct size. It all depends on how much work you want to do.
It would have been a lot easier to just leave the tailstock die holder back at the garage sale! :-)
Hex dies are normally a fixed size. Circular dies are split so that the size can be altered slightly. That's what the 3 screws on the die holder are for. The central one screws into the split to push it apart and increase the size, the outer two squeeze the die together to close the split and make the size smaller. Many close tolerance applications require the thread to comply to certain limits and fits. A better finish can be achieved on some steels by cutting the thread in two passes. The hex type are particularly useful for repairing a damaged thread, especially where it cannot be removed. Hence the term rethreading or thread repairing. There are a number of fixed size dies becoming available. Generally these are cheaper and their quality can be suspect. I have only had one set in UK. Couldn't tap butter with it. That set is some years old and quality may have improved but you cannot beat a real die from a well known maker, US or British.
Hex rethreading dies are normally the same size as the nut used for that size thread. Thus they come in many sizes.
There are also fairly common hex dies intended for home-workshop uses, and sold at home centers and hardware stores. These are all the same sized hex, something like 1" across the flats. It is most likely these that you have. They are probably not the best quality, but adequate for routine uses.
Yup, and they work like crap for threading new stuff. Sears used to have decent split round button dies, I've got a bunch, carefully hoarded. These days, about all you can get is Hansen from the hardware store, if you can find a hardware store, and they're hex dies. Those also work like crap for originating threads. One local hardware store carries Varmint American dies, those are round, but not split, marginally better than the hex ones but not much. MSC, et al, seem to be the only places you can buy decently working split threading dies these days. The hex dies don't seem to have much of an edge, they just kind of roll the threads instead of cutting them. There's also no adjustment possible with them. They leave very ragged new threads, where they leave threads at all. I had one chunk of aluminum just turn into a passible imitation of a fir tree twig after I ran one of those hex dies over it, even with cutting compound. A round split button die left polished threads on the same chunk. The stuff was some of that nasty, extruded, home improvement-joint rod stock which machines like bubble gum, but it does show what's possible with the right tooling.
Hex dies are good for debuggering studs and bolt ends in places where you can't swing a regular die stock, you can just hunt up the appropriate socket or wrench and use that. IMO, they just aren't designed for originating new threads and would probably work very badly, if at all, in a tailstock holder.
I didn't know of the difference when I bought mine. I got the HSS set from from Sears several years ago in a catalog sale. I did thread a 1/2 steel rod yesterday as a test. It was very slow going, but looked ok. With the adjustables would you start with it larger, then go over it again at the proper size? Would it thread faster that way? I threw in a 1/2 alum rod in the lathe yesterday as my 1st attempt to thread on it. I was thinking you can cut aluminum faster so I didn't set it on a slow speed (Braing cramp). The carriage hit the microstop and pushed it into the headstock. Then the shear pin broke. (It took a while to figure out why the leadscrew wasn't working after that.) Now I know what the pin was in the toolbox was, a spare shear pin. After that I got a thread made. Not perfect, but not bad for my 1st try.
I did see Enco has a cheapy HSS set with adjustable dies.
Anyway I might need to make some english/metric adapter studs for my younger brother. It seems like threading on the lathe will be faster than doing it by hand with a die.