In this video I'll show the upgrades I made to the CNC mill i built in my previous video:

   • CNC Mill for under $100  

I upgraded to a 500W spindle and built an all-aluminum head assembly, widened the bed, increased the rigidity of the X axis with thicker rails,
installed higher torque steppers on X and Z, and dramatically reduced backlash on all axes by using a double-nut arrangement on my leadscrew

carriages.

The machine is still far from perfect, but cutting aluminum is significantly easier now, and with some adjustments / tightening down / tuning, I

think it will be able to reliably hold tolerances that are at least good enough for one-off hobby projects.

Currently the most obvious weakness is flexibility in the Y axis due to using only 8mm rails.

The board firmware is unchanged from the previous video. I'm still using an arduino Uno with GRBL firmware driving A4988 stepper controllers.

Some links to relevant hardware:

500W Spindle kit:
https://www.amazon.com/gp/product/B01...

92 oz-in Stepper Motors:
https://www.amazon.com/gp/product/B00...

16x500 mm Linear Motion Shafts:
https://www.amazon.com/gp/product/B07...

16mm Bore Linear Bearing Blocks:
https://www.amazon.com/gp/product/B07...

Linear rail for Z axis:
https://www.amazon.com/gp/product/B08...

500mm T8x8 Leadscrew:
https://www.amazon.com/gp/product/B08...

150x70x9.5 Heatsink:
https://www.amazon.com/gp/product/B08...


Software used for CNC:

Universal Gcode sender

FreeCAD 0.18


STL Files:

https://www.thingiverse.com/thing:532...


Feeds/Speeds

RPM: 12,000
Bit: 1/8" 2 Flute End Mill
Horizontal Feed: Between 500 - 1500 mm/min
Vertical Feed: 10 mm/min
Stepdown/Cut Depth = 0.05mm
Finishing Cut Depth = 0.01mm

I found that for the same amount of volumetric removal rate, a higher horizontal speed with a smaller depth of cut gave better results because of

reduced chatter/vibration. For example, 1500 mm/min at 0.05mm depth of cut was much smoother and had less chatter than 750 mm/min at 0.10 mm

depth of cut. Unfortunately this does put all the work on the very tip of the end mill, but because this machine is pretty limited on

power/rigidity, that's the only viable way to cut.

Music Used:
Eric Skiff - Underclocked
Kevin MacLeod - Groove Groove
Heatley Bros. - Luminare
Serge Pavkin - Elevation