In his book on Cartridge Case Conversions, George Nonte gives plans for a hydraulic jack powered press for swaging one case down into another. I built my own updated version about 35 years ago. (2 12"x1" square steel plates separated by 1" all thread rods at the corners- double nutted on the outside for extra support. The top plate has a 7/8x14 threaded hole in the center. George's press used a 2 ton jack, mine uses the only jack I had available at the time:20 tons!
I made dies from plumbing reducing bushings (1/2" black pipe is threaded 7/8-14!) The drill out the center and hone or sand to desired Internal diameter.
Over the years I have made 20 caliber bullets into 19 and .338 Winchester bullets into 330 bullets for 8x56R Hungarian. I have pressed bearings in and out of machines and straightened warped steel targets also.
I don't have a lathe or the skill to make threaded dies. But I have opened High Speed Steel dies for making larger neck areas on dies.
At gun shops and yard sales, I never turn away reasonable prices loading dies for any cartridge. They are a cheap source of nuts, stems, rods, bushings and bodies that are already threaded in pitches that are common to reloading!
Ivan