Sherline Lathe Project

Projects
5

Bit of an update on this.

Controller

I’ve decided, after some real pondering, not to go with the control computer that is already in the cabinet. I’ve had some success on another project building a driving board for larger steppers from a GRBL board (replacing the slot-in stepper drivers with just obtaining the step/direction/enable).

I’m going to replicate that using GRBL-mega and a RAMPS 1.4 board. An old Raspberry Pi will be the host computer and you can use a laptop or machine around the space to upload gcode via cnc.js

A few things contributed to this decision:

  1. Reading some of the problems with a parallel port and indeterminate state didn’t reassure me:
    [VHS Group Project] Sherline CNC mill - #30 by xquared
  2. If (and really, when) the CNC computer dies, getting a decent replacement machine with a good parallel port is increasingly more difficult
  3. cnc.js is really slick
  4. Going with a RAMPS/GRBL Mega is pretty cheap and easily replaced if needed.

Spindle Motor

I fired up the old spindle motors and I’m not super impressed. They aren’t horrible, but given the time investment, and some silly things I’d rather not go in to detail about, I’ve decided to go a different direction with the spindle motor. I’m actually going to try to drive the spindle via a large stepper/servo hybrid motor.

I’ve purchased a 2Nm stepper/servo hybrid motor and power supply. I built a little test rig to see how it operates and I’m pleased so far. The plan is to allow this motor to be driven both by the controller’s spindle PWM as well as. a C axis. I’m hoping that this can potentially become an XYC horizontal mill in addition to a lathe, giving us the ability to do some very interesting milling operations in-place.

Wednesday

I’m headed down to the space on Wednesday Night to work on the little beast. Here’s my todo list, hopefully I get through a lot of it. If anyone wants to join, please give me a heads up so I can plan distributing work.

  1. Move all spare parts into a box
  2. Remove the PC
  3. Evaluate the electrical box, document current connections.
  4. Clean the machine and lubricate
  5. Remove old controller and store
  6. Install Arduino/GRBL/Pi/Power Supply
  7. Install endstops (may require part fabrication)
  8. Test motion
  9. Install new spindle motor (may require part fabrication first
  10. Design safety enclosure
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