If you own or have considered buying the Pittsburgh 14 Piece Hydraulic Punch Driver Kit from Harbor Freight item #96718, you might have one complaint. The size holes it makes are oddball because it's made to fit conduit and pipe since this tool is primarily for the home building/remodeling field so they can punch holes in metal studs quickly. So while the die says 2-3/8", it will actually punch a hole 2.403!
But, what if you want more from it for other purposes?? If you have a lathe and mill, you can simply make dies of the size you desire! What I present today is the prototype and does this thing punch holes! (mine are the silver color dies sitting next to the H.F. black dies) I only used 1018 steel to make it but punching a few holes didn't even phase it. Unless your planning on doing thousands of holes, I think the non hardened steel will hold up decently. Worst case is you would have to sharpen it up a bit now and then. Of course, stainless steel or steel that you can heat treat would be an upgrade if you preferred.
My prototype size makes a 3/4" hole. I plan on making a nice assortment of normal size dies such as 1", 1-1/4", 1-1/2", etc. I'm even planning on doing a square die! Maybe a 1 inch square to start out.
Now I couldn't just stop there. How about a way to dress that hole up? I made a prototype 3/4" dimple die modeled after the expensive store bought units to go with it. It works GREAT! (don't mind the finish quality, it's a prototype) I just lightly squeezed it in my vice but you could use a press too. A block and hammer might even do... This again is 1018 steel but I can't imagine wearing this out for what my use will be.
I guess I have a few cutting dies and dimple dies to make... (nicer finish quality of course!) lol