I Wish Mitch the Kool-Smoking Mormon Were Here

I have my belt grinder in more-or-less usable condition.

It was quite an ordeal. Jobs like this remind me of what Charlie Baltimore said in The Long Kiss Goodnight: “Yeah, well, that’s the thing about being a secret agent, Mitch. Nothing is ever simple.”

I love that movie. Brian Cox should have gotten an Oscar for the scene with the dog.

I ordered a metal box for the VFD, because you can’t mount a VFD in areas where metal filings and abrasive dust are loose in the air. Had I been aware VFD’s were so fragile, I would have ordered a KBAC VFD with it’s own little hazmat suit. I had to pay over thirty bucks for a metal box from BUD Industries.

The box had knockouts all over it, and you can’t screw anything to a knockout. I had to cut a piece of aluminum channel on the band saw and then turn it into an adaptor plate using the mill. I then had to drill and tap holes in the plate so I could screw it to the box and screw the VFD to the plate.

I got the VFD installed in the box, and then I had to run the AC and motor wires to it. That was fun. I had one knockout that refused to move, so I had to spend half an hour ripping it out and polishing the hole with a rotary tool.

The plan was to have this: 250V plug ==> cord ==> box ==> VFD ==> motor wires ==> VFD. I got it all put together, and then I had to deal with the control panel.

No one wants to use a tool that has a control panel inside a metal box with no windows. It’s a pain. Luckily, I had a VFD with a panel that detached. You can run an ethernet cable from the VFD to the panel, and you can put the panel out in the dangerous world of grinders and dust, where it’s easy to reach. This was my plan.

How do you run an ethernet cable through the side of a steel box. You don’t. You have to find a special coupling that has an ethernet jack on each end. You mount it in the box, and you run a short cable from the VFD to the coupling. Outside the box, you run a long cable from the coupling to your control panel.

Here’s the coupling.

Ordering this stuff is simple, right? No. First you have to know what to call the coupling. I finally found that out, and then I was able to search on Ebay. Almost no one in the US sells these things. I finally found one, and then I had to wait for shipping. I also found two cables at Monoprice, which allows you to buy cables in any length you specify. Neat.

Today I finished throwing it all together. I put the coupling in the box, and I ran the cables. I made a little aluminum mount and screwed it to the grinder platform. I screwed the panel to the mount. I was ready to go.

I did one other thing I’m happy about. I put a twist-lock plug and receptacle between the VFD box and the motor, so if I have to work on this thing, I can break it down into two major parts without opening anything up. Very nice. I love using twist-lock plugs on motors. I don’t know how OSHA feels about it. They are welcome to drive out here and give me a citation.

My final accomplishment was programming the VFD so the cooling fan didn’t run all the time. The VFD box is not vented, so a fan inside the box will actually heat it. Not good. Also, it wears out the fan. I found a programming parameter that makes the fan turn on when the VFD is hot. I have to wonder why that wasn’t the default setting. Why would a cold VFD need air?

I couldn’t find an ideal location for the panel, so I just put it in front of the grinder, out of the way of the belt. We’ll see if it blows up. Here’s a photo.

This is excellent. I now have an abrasive cart with two variable-speed belt grinders. What useful machines. I actually used them to make the aluminum panel mount. Abrasives are seriously underestimated. If you can’t grind and sand, you’re handicapped.

Now I guess I can make knives.

On to the next challenge. The excitement, as always, is palpable.