The anti-backlash nuts minimize any play between the nut and the leadscrew. Thrust bearings keep the leadscrew from moving axialy when direction changes.
The HobbyCNC design intends for the stepper motor shaft to keep the leadscrew from any axial movement. This works fine for the lightweight wood design. More machine weight or a loose motor shaft can cause more backlash than you want to compensate for with the software.
I got the 125 oz-in motors and I could push/pull the motor shaft about 0.045 in. The thrust bearings (several designs in this forum) can be placed at each end of the leadscrew to bear the axial thrust of the screw rather then depending on the motor bearings to take that load.
Also:
I used 1" drill rod for my X axis and 3/4 for Y and Z. The Igus bearings are doing great. I had to hone the holes I pressed them into to get the right fit. I mounted a Porter Cable 1.75 hp router on my machine.
Bill |