Do I need a keyway?

[kingcreaky]

what he said....

[birchy]

Fair play Jonathon, you always impress me with your facts and figures. I'm more of an "over engineer it, guarantee it'll work" type person. But then again I used to make parts for massive steel bridges when I was an apprentice!

I have to admit that I'm VERY surprised the load is so small when converted to Nm via the ball screw and pulleys. Obviously I'll have to be a bit careful with the acceleration/deceleration but I'm more interested in accuracy than speed and would rather err on the side of caution than bollock the machine flat out and end up wearing it out prematurely.

Thanks everyone for your replies. Not needing keyways is one less headache to worry about. Just for the record, I'll be using M4 or M5 grub screws at 90 degrees, dimpling the shaft slightly and applying a little Loctite for the final fit.