Hi All,

Soon I'll be undertaking a new project to replace my CNC'D BF20 which I've outgrown.

Proposed specs:

  • 520x, 280y, 550z travels
  • X and Y motors will be 600W AC servos (Chinese)
  • Z motor is yet to be decided on.
  • Possibly a counterweight/gas spring to help lift the Z axis (the head alone will weigh over 80Kg)
  • 2505 double-nut ballscrews on all axes
  • HIWIN 25 rails on all axes
  • 2.2kW (3.7kW peak) Servo-spindle (10.5N.m from 0-2000RPM, top speed of 8000rpm, Chinese product)
  • BT30 spindle cartridge, 12000RPM max speed. (Chinese product)
  • Pneumatic/hydraulic tool release mechanism (comes with the spindle).
  • Table will be donated from an old RF45 - that will have the dovetails milled off for the linear rail bearing blocks.
  • Machine will be controlled by a KFLOP/Kanalog combo with Mach3/Kmotion



Machine will primarily be constructed of thick-wall tubular steel, welded together and stress relieved before being machined.
I'm thinking about epoxy-sand filling all the hollow sections to avoid the dreaded ringing that's almost certain to occur on a steel structure. Will see what the community says...
Solidworks estimates the weight to be about 400Kg at this stage.


Anyway, half of the components listed are already in my possession, so it's not so much of a fantasy.


You will notice a lot of detail in the photos is absent - namely how the axes are slaved together and other detail like that.

I'm looking for any input that could help.