This escape from flatland started with the purchase of a suitable Z-axis motor. For me, this meant a match to the SEM MT30 servos on my X & Y axes, for no particular reason beyond knowing I can tune one of these to my Dugong drives. A quick trip to eBay revealed a decent price on an “R” version of this motor. This means it’s a little longer and more powerful than the “M” versions already on my machine (the further down the alphabet you go, the longer and stronger the motors get in this long-since-retired line), but it shouldn’t matter much.
The seller was happy to sell motors individually, having taken three off of an old machine. I took the left one pictured below:
It was only after a couple of back and forths that I took notice of the eBay seller’s name, “marty_in_mesa”. Hmm, that seems somehow familiar. My suspicions were confirmed at the end of our conversation when out of the blue he recommended the Centroid All-in-One for my conversion. Yep, I bought the motor from this forum’s very own Marty! By the time I figured it out, I didn’t even bother introducing myself. I will say, he was lightning fast and helpful with his responses to my questions, and boxed up the motor and sent it out the very day I paid for it. Two thumbs up for Marty.
I received the motor a few days later and popped off the encoder cover to see what was under there. Looks like a 500 line encoder; no worries the plan was always to install the third 2048 line Calt encoder I bought a couple of months ago when I was working on X & Y.
Under the encoder we find the tachometer assembly typical of these motors and a 0.250” shaft. That’s a minor bummer, since my encoder wants a 6mm shaft:
Fortunately, it’s not hard to find 6mm to .250” shaft adapters. Yet another Amazon box later, this problem was surmounted:
A little trickier was the fact that the encoder face has a raised boss around the shaft bearing that prevents the encoder from sitting flat on the motor’s encoder riser. This required me to bore a recess into the riser. I found the center of the hole using my probe and CNC12’s bore probing routine. My first real use of the probe, and it couldn’t have gone more smoothly:
After that, it was a matter of wiring up the encoder, power, and shield and threading it through the liquid-tight conduit I had cut to length and fitted with appropriate screw connectors:
Next update: Installing an Elrod Z-axis kit, and mounting the motor to it. Spoiler alert: installing the Z-axis kit was not as fun as it really should have been, but I won’t dwell on that, having vented about it here.
It gives wannabe machinists like me something to aim for.