Mill - Mods & Upgrades – Spindle Motor Controller

I hardly had my machine up and running and I burned out the spindle motor. True to their reputation, Grizzly Customer Support was right on the ball, and had me a new one in no time. I’m sure I was pushing the motor to hard, so made a practice of not pushing it so hard, but then I found that the motor controller was also pretty easy to burn up. I went through two of them! I decided that wouldn’t do, so I hunted around the internet for a robust replacement. I wasn’t ambitious enough to overhaul and redesign the whole electronics package, just find a better replacement than the factory stock part.

My research lead me to KB Electronics and the KBIC-120 Variable DC motor controller. It turns out that the controller is something of an industry standard, so there are actually quite a few manufacturers, but selected this one because it had the best documentation. It turns out they even have a distributor right here in town, and I went down and stood at the will-call desk and they even had it in stock. They insisted if I had any problems that they have electrical engineers on staff that would be happy to help diagnose and resolve any issues. It turned out to be cheaper than buying a replacement from Grizzly (though I didn’t need to because it was still under warrantee) but what Grizzly couldn’t help me with was upgrading it to be more robust.

I got one that would drive the motor without burning out, and an aluminum heat-sink to mount it on so it would be far from the danger of over-heating. While I was at it I got a fuse assembly just in case I DID over tax the components.

Silly me. I imagined I could stuff all that crap back in that tiny little box, but one look told me that was impossible. That’s not such a bad thing because that box is probably a big contributor to the over-heating of any electronics inside it.

So I cut a hole in the back and made some clever little mounting brackets and put the whole affair on the back of the box. I’m sure that was a wise move because in playing with it I discovered how HOT that thing actually gets, so now it gets LOTS of circulation. I figured, “What the heck!” and put a cooling fan on it as well. And I figured as long as I was at it, I drilled a bunch of holes in the motor shroud and put another cooling fan on that as well. My son said, “Dad, as long as you gotta put a fan on that thing, let me show you what to use.” So we went down to Fry’s Electronics and picked out a PC cooling fan with some blue LEDs on them, so I tell you what – I got the COOLEST looking mill in town now!!!

You’ll notice that like everyone else I’ve seen, the little safety-shield was one of the first things to go. It’s too small to be practical, and always right in the way. Bypassing the safety switch was easy to do by simply rerouting some wiring in the electronics box. Not to worry, shielding is a big deal, not only for safety, but for mess containment. So see my section on that subject.