My (former) Sherline CNC Mill

	This mill started as a stock Sherline 5400, with travels of X 9", Y 5" and Z 6.25".
	I relocated the spindle motor behind the column to balance the head about the Z ways to eliminate stiction and enable silky-smooth and precise Z-axis moves. The idler pulleys were equipped with ABEC 7 skateboard bearings (size 608ZZ). The belt was Mitsuboshi brand--the same as the OEM Sherline belt.
	I installed the 10krpm pulley set and my quick-change motor mount (change from high to low speed range in less than 30 seconds) inspired by the Sherline 10krpm mount. The spindle control box was outfitted with a DigiSpeed controller card (allowing spindle speed control through the gcode program) and I added a filter cap across the DC spindle motor brushes to minimize EMI. I wired the spindle motor with Molex oil-and-water-resistant cable. The stepper motors (134in-oz holding torque) and mounts were Sherline's, and were fitted with Belden "Infinity" high-flex-life cables, suitably strain-reliefed.
	I replaced the brass leadscrew nuts with Moglice 1000 for minimal backlash. This Teflon-bearing cast polymer is widely used in making accurate leadscrew nuts and rebuilding full-size machine tool ways. I mounted the Z-axis leadscrew nut rigidly to the head--no adjustments to fiddle with.
	The driver box had a 3-axis Xylotex driver card, 24V switching power supply, high-efficiency switching converter for the 5V logic supply, filtered power entry module, fuses on both AC and DC, optoisolated input lines, ferrite EMI filter beads on all output lines, and a metal EMI fan filter. For the stepper cable attachments I used Radio Shack CB microphone connectors with threaded locking rings.
	I mounted the mill on a 1/2" cast aluminum tooling plate (on 1" standoffs to allow better chip cleanup,) with .090" aluminum backspash with two 2-bulb fluorescent fixtures, and an .090" aluminum snap-on front chip shield.
	I ran the mill on TurboCNC 4.01, with rapid set at 20ipm (although 30ipm rapids were possible.)

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