Ha, it must be a 4". I remember doing the math when I built it. I wanted more pressure but as you know what you got is what you got unless you spend more. I do have it turned up as high as it goes.
The billet is sized to a little under 3/4" using flat dies with spacing stops on a press. The twister uses sockets made from 3/4 " socket extensions, one of which is turned down to fit in the drill chuck.
At Automation Direct, the correct gear reduction (60:1) is $261 and the 1 hp motor (1750rpm) is $253. I'm pretty sure I could source the rest of the parts under $500.
Merry Christmas to all. This pair (I finished several days ago) are the last going out before Christmas.
And another that is waiting for someone to love it more than me.