The ACMe screw is 12.9mm and the stepper shaft is 9mm; well actually is 4 mm, but it has a tooth pulley, which I was not able to remove. I have no access to a lathe, so I made my own ghetto.
Using the Z-axis carriage to hold the screw, a hand drill on one end for turning the screw; and on the working end I used a dremel for reducing the diameter to the 9.1 mm
Since the drill has no holding button, I had to use a clamp for keeping the drill ON while filing the other end
It took me like 5 minutes to get the end ready
The rug under the carriage is for noise isolation; the rotating screw when contacting the dremel made vibrate the carriage and then the table. It worked!
+1 for the ghetto lathe! I did something similar myself to grind the ends of my lead screws down. I actually attached a pulley to the lead screws and ran it with an induction motor though. I also did the rough grinding with an angle grinder. Then I finished it up with files. I run rubber hose couplers, so good enough.
@Paul_Frederick what kind of hoses? the ones used for car cooling (rubber reinforced with a nylon mesh)? and what did you use for holding it, clamps or zip ties?
@Nelson_Trujillo
I use quarter inch high pressure reinforced fuel line. Because that is the size of my motor shafts. I use hose clamps to hold it too. So I had to turn my half inch diameter lead screws down to quarter inch so the hose would fit good.