Sherline lathe z-axis CNC conversion

thingiverse

# Sherline lathe z-axis CNC convetrsion Liked the original design which mimics Sherline's CNC kit. However, the plastic body flexes a bit and yields too much backlash. Since then, I came across an old Denford Microturn, and copied it's simple approach here, which is just a thrust bearing and clamp type flex coupler. I am able to get less than 0.005" total backlash, which also includes the slack from leadscrew and saddle nut. This is good enough for now, as most of the backlash can be taken out by software or care. Decided to keep the option open so that it's possible to upgrade to Sherline's CNC solution in the future. The two drilled holes are positioned far away from Sherline's mounting holes. Please note: this motor mount as is only works for lathe z-axis. The same design can be modified to fit the cross-slide or mill. 09/25/2020: did a similar conversion on cross-slide (need to reduce the spacing and size of mounting holes), got only 0.002" backlash. # Steps after print 1. remove hand-wheel 2. use printed mount as template to mark the two holes with a transfer punch 3. drill and tap two 8-32 holes on lathe bed 4. insert thrust bearing and flex coupler, squeeze the coupler while tighten its screw 5. mount the printed motor mount 6. mount the motor with 8-32 screws which should self tap into the plastic. As shown in one of the photos, it's better to engage hex wrench with flex coupler screw before mounting the motor. Since there are two possible orientations for the coupler to clamp on, as well as possible small offset in relative position; it's a good idea to put a small dot on the print to remind you how to angle and position the hex wrench when you need to take it apart in the future. 7. mount the hand-wheel # Parts needed* The following are eBay affiliated links. Please support open source projects like this. 1. [flex coupler, clamp style](https://www.ebay.com/itm/1pc-Flexible-Coupling-Clamp-Shaft-Coupler-BR-D20-L25-CNC-Stepper-Motor-Connector/283620977380?ssPageName=STRK%3AMEBIDX%3AIT&var=584916093743&_trksid=p2057872.m2749.l2648&mkrid=711-53200-19255-0&siteid=0&mkcid=1&campid=5338743758&toolid=20008&mkevt=1) 2. [thrust needle bearing](https://www.ebay.com/itm/2-PCS-NTA411-1-4-Thrust-Needle-Roller-Bearing-With-Two-Washers-6-35-x-17-45/263617564480?hash=item3d60d4cf40:g:NH0AAOSwuTxV-6co&mkrid=711-53200-19255-0&siteid=0&mkcid=1&campid=5338743758&toolid=20008&mkevt=1) 3. [dual shaft NEMA23 motor](https://www.ebay.com/itm/NEMA23-185oz-in-3A-Stepper-Motor-Dual-shaft-KL23H256-30-4B-4-wires/152222333674?hash=item2371287aea:g:kRYAAOSwucVfDm-P&mkrid=711-53200-19255-0&siteid=0&mkcid=1&campid=5338743758&toolid=20008&mkevt=1)