# Home-built ER-32 lathe spindle



## DICKEYBIRD (Feb 12, 2011)

I guess this should go here as it's part of an ongoing modification project on my Denford CNC MicroMill. Got it last summer off Craigslist real cheap. It took me a while but finally got it working pretty decent by hacking into the control and converting it from serial control to parallel and using TurboCNC in DOS with an old 386 laptop. Believe me, I ain't smart enough to do all that on my own but the guys over on the Denford (U.K) forum and the HSM forum steered me straight.







I decided to mount a treadmill motor driven ER-32 spindle assy. to the left side of the enclosure and do simple lathe ops by mounting a tool holder on the left end of the X/Y table and controlling it via CNC movements of the table.

I built up the spindle housing from 3" square, 1/4" wall steel tubing with 5/8" thick steel plates pressed into the ends and locked in with 16, 10-32 countersunk screws. I trepanned the bearing holes (whole 'nuther story there!) and line bored them on the lathe for a light press fit of the 55x30x13 mm deep-groove bearings. The spindle is a modified CTC Tools 32 mm x 100 mm straight shank ER-32 collet chuck. I bored the center through-hole out to 21 mm and turned & polished the shank to 30 mm for a push fit of the bearings.

I made the pulley and spanner nut and threaded their ID to 1.125x18 tpi to match the thread that I single pointed on the end of the spindle shank. I set it up with just a slight amount of preload and will do some further adjustments by temperature rise once it's in place and running at top speed (2500 rpm.)

Any way, here's some pictures after I finished it with a couple coats of Rustoleum Hammertone Silver.
















Now that the spindle's done, I have to add a steel tube stiffening structure under the enclosure, mount up the motor, wire up the KBIC-120 speed control and make a toolholder like Chuck made in his Minilathe mod thread. I'd been scratching my head until I saw that...thanks Chuck!


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