ShopSmith 10ER Treadmill Motor Upgrade

Basement, Blog, Woodworking / Wednesday, April 18th, 2018

When I bought my ShopSmith 10ER, I had only the vaguest idea of what it was and how I would use it. I knew it was old and I knew there were fanatics out there, so I figured I’d be good to go on whatever I needed to learn about it.

The guy selling the ShopSmith lived over an hour away, so I had committed to buying it before I even saw it. It didn’t seem worth it to drive all that way to change my mind.

It was the first major power tool I owned as well. The only others were a drill and a circular saw. This ShopSmith was hefty and does so many things I still don’t know how to accomplish. That’s a good thing, I’m learning everything as I go and only buying one machine to learn it all.

But because I had never owned a power tool of this magnitude before, I didn’t really know what I was looking at and even if I had all the details, I doubt I would have been able to figure out what it would mean to me. I’m looking at you 1/2 HP AC motor and pulley system.

The way the ShopSmith is set up, the motor has three pulley sizes on it, and the headstock has three sized pulleys on it too. You can mix and match for a variable speed. However, it’s one more thing to configure on a machine that already needs a lot of configuring when switching between tasks. But since it’s what I had, it’s what I worked with.

Then I acquired a second ShopSmith and it had a 3/4 HP AC motor on it. I thought to myself, more is better, right? So I went about trying to figure out how to swap the motors. A previous owner of my ShopSmith made that difficult. They had wired in a forward and reverse switch as well as an electrical outlet. Even with the immensely supportive help of the ShopSmith forums, people who know these machines better than anyone would think, I was not able to swap the motors and keep the same forward and reverse function. The reason was that electricity scares me. I don’t like messing with it, especially if it’s already working, it’s more complex than it needs to be, and also if we’re talking about high voltage. Much to my dismay, I needed to abandon that quest.

ShopSmith switch forward reverse

I stepped back after that and asked myself, what is it that I’m trying to achieve? I wanted more power and I wanted to be able to control the speed of the motor on the fly. That’s where I started my searches. What I found was that I would need a DC motor and motor controller, and a motor with more horsepower, of course. That’s when I stumbled upon treadmill motors and their post-treadmill applications. A number of the YouTubers I was watching had featured projects where they integrated the found motors into their homemade shop equipment.

After a few weeks of keeping an eye out for a treadmill to harvest one from, someone kindly posted a treadmill motor on Craigslist. They were asking $40 for the main drive and the lift motor. I only needed the main drive, so I offered $20 and we had a deal. I’ve since tracked down replacement motors for this treadmill and found they run $450, so I think I got a decent deal.

The motor I got was a 3 HP DC motor. It had no power or speed controller with it. But it only had two wires coming off it, so it didn’t seem like it would be too hard to get it going.

And really, it wasn’t.

After finding this video, I had all the information I needed to build my own motor controller and power supply.

I jumped on Amazon and ordered the parts I would need. I ended up having to order a second motor controller because I tried running it without wiring in the rectifier and it fried something in the controller. I got impatient waiting for the rectifiers to ship from China. Live and learn.

I also bought a safety power switch to wire in and cut the power on the fly. 

To be entirely honest, wiring it all together was a whole lot easier than I expected it to be. For someone who is terrified of working with electricity, it went about as smooth as I could have asked for.

Once the wiring was in place, I needed to find a way to attach it to the motor. To do this, I bought a plastic electrical junction box and mounted everything inside nicely, cutting holes for wires and so the controls could be accessed. I was fortunate enough that the motor had a convenient hole on the mounting bracket to which I could attach the electrical box. I was also fortunate enough that the holes on the mounting bracket lined up with the mounting bracket on the ShopSmith. It was a relatively easy swap.

The first time I turned it all on, hooked up to the ShopSmith, I was nervous to turn it all on. What if I had done something wrong and everything broke. Clearly, that was the worst case scenario, but it doesn’t hurt to explore all options like that. Instead it spun to life, slowly at first and then faster and faster. It took me a few tries before I felt comfortable bringing the motor up to full speed on the ShopSmith. I knew the motor could handle it because I had done so prior to hooking it all up, but I was less sure about the ShopSmith. It has a maximum speed rating, but I had no idea how fast this thing was actually going. That’s a future project, attaching a cheap, digital tachometer to help me set the speed.

Once I started using the ShopSmith with wood, I noticed the difference I had implemented. Before, soft woods like pine would bog down the motor and it would stop while on. Now, I could have the blade spinning quite slow and it would still cut through even the harder woods like oak. It was an upgrade worth making.

Mounted ShopSmith motor control

All in, I estimate I spent less than $100 on this upgrade. Much cheaper than buying a new table saw with equal capacity.

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