Lead-screw Conversion
Last updated on Tuesday, March 19, 2019 11:45:18 AM Mountain US Time Zone


Lead Screws, Split Nut, Anti-backlash Nut Adjustment, Stepper Motor Couplers

Converted the mill's lead screw, nut, & bearing assemblies to those for CNC & NEMA 23 stepper motor mounts.

Lead Screws

The Taig CNC conversion kit: lead screws with bearings & bosses, adjustable bronze nuts, couplers, &
NEMA 23 stepper-motor mounts. The nylon tubing is cut diagonally (45 deg) into 3/4" long coupling pins.
There are 4 pins per coupler. The diagonal cuts can assist in assembly.

Leftover parts from the conversion provided a precision ground 1/2-20 left-hand lead screw with bearing plate &
bronze nut assembly thus allowing the implementation of a very useful upgrade to the 9x20 lathe cross slide.

The NEMA 23 motor mount screws onto the finely threaded boss & is clamped into place by a ring & set screw.
The bronze, zero-backlash nuts have two (outside) clamping screws & one (center) locking set screw.

Split Nut

X-axis install. The bronze split-nuts work much better than expected. White lithium grease is a good lubricant.

Anti-backlash Nut Adjustment

X-axis nut. To adjust the anti-backlash nuts, first remove the stepper, unbolt the bearing plate &
push the slide until the nut is exposed. Loosen the center set screw, then one at a time, tighten the
outer screws until the lead does not turn, then back-off a 1/4-turn. Re-tighten the center set screw.

Y-axis anti-backlash nut.

I used a wrench to feel the lead screw tightness.

Stepper Motor Couplers

X-axis boss & coupler. Do not over tighten the lock nut as it can bind (break) the bearings that are inside the boss.

Y-axis boss & coupler. Note the four holes for the 3/4" long nylon coupling pins. A simple yet effective coupler.

Z-axis boss & coupler.

X, Y, & Z-axes lead screws now converted for CNC.



Click on linked thumbnails

Lead Screws, Split Nut, Anti-backlash Nut Adjustment, Stepper Motor Couplers