Shrapnel Spindle


Building a spindle for the Shrapnel CNC mill.

Start off with a hunk of 2.25" square extruded aluminum.


Hack it in half with your aluminum hacking device.


Clean up the ends with your mill so they are square, then lay out your ER16 collet chuck to see how it is going to go together.


Bore some precision 42mm counter bores on any handy CNC mill or lathe for the bearings.




Press everything together with a hydraulic press or the like.


Double check that everything looks good on the pulley end.


Yep, all is well on this end too.


Check for runout. Looks like we've got .001" runout, so maybe we can move the collet around to find the sweet spot.


Bore a few holes and counter bores for mounting the spindle to the Shrapnel.


Bolt her up.


Sit back and relax, admiring the cool new spindle.


Got the new 100Vdc motor mount finished up. You can also see the optical encoder pickup for the micro tachometer.


Gearing is about 4:1 which is giving roughly 5k RPM at the tool.


I painted half of the shaft with flat black paint and this is what interrupts the beam on the optical pickup.