Lathe Motor Upgrade

Amazing value motor for an amazing price.

The old Advance Lathe I have is awesome, but it’s a pain to adjust the speed of it, and you don’t get to much in the way of low speeds, you basically get fast, faster and really fast. Before I pulled the old motor off, I didn’t have a way of measuring the RPM of the spindle, but I’d hazard a guess that it spins at the top end of what it should spin at even on the lower pulleys.

The old motor looks a bit rough, but it seems in pretty good shape mechanically. I’ll be holding onto it until I find a more suitable project to put it it.

Wanting more options for speed adjustments, I decided to upgrade the motor.

There are several options for a new motor. The first being a 3 phase motor with a VFD. Even going with cheap motor and controller from ebay or similar, they get pricey quickly, and even on the bottom end of the motors, they output more power than is reasonable for this little lathe.

Another popular option is a motor from a discarded treadmill. It was a tempting option, as the price is usually virtually free, as a lot of them basically get given away. But then I’d have to mess around with mounting, controlling, finding a treadmill with a usable motor etc… it’s doable, but a fair bit of hastle.

I even looked at trying to run a high powered brushless motor made for radio controlled cars. you can get some pretty grunty ones these days and I found a hand full of people doing the swap online. Once again, it’s a hastle with mounting, controlling, reducing the speed etc…

The final option, which is the option I went with was a brushless motor configured for running industrial sewing machines. They are sold on Ebay and the usual places for Consew machines (and maybe a few others) The motors are 550 watts, or 3/4 horse power, which is a step up from the old 1/2 horsepower motor that was on it originally, but not so much more that I’m going to start breaking things elsewhere. More concern is the fact that the old motor is rated at 1440rpm, where the new one will do a maximum of 4500rpm, which is a lot higher.

For about $100 Aud, I got everything I needed to mount and control the motor.

The motor installation was pretty straight forward, thanks to the new motor coming with it’s own adjustable mounting bracket.

Mounting the motor was easy. The kit comes with a motor mount that pivots. Once I unbolted the old motor, I sat the motor in position, and got things lined up. You can move the motor in and out a little on the mount, which allows you to get the pulley aligned with the other one easily.

I had to drill an extra hole, and mount a bit of angle iron to get a bolt on the motor side of the mount, but it really didn’t take much effort or time at all.

The motor controller was mounted to a piece of wood, and then screwed to the lathe’s support with self tapping metal screws and an L bracket. The speed adjustment leaver simply screwed onto the left hand side of the lathe’s support, again with self tapping screws.

Here is a good shot of the motor controller and the speed adjustment leaver.

From new, the Advance lathes had a top speed of around 900rpm so my aim is to have it run at around that speed. It only has plain bearings, not roller bearings, so are a lot easier to damage.

The pulley on the new motor is a lot smaller than the one on the original motor. That is handy as it reduces the speed a little out of the gate.

Initially I didn’t have a way to check the spindle speed, so I was running the motor at around 2000rpm on the controller, and it was giving me a fast but not too crazy speed.

I borrowed a non contact tachometer from my work, which allows me to get an idea of the spindle speeds. Having a play around, on the lowest speed pulleys, I could get the motor to run between around 70 to 700rpm. This is awesome, as it allows me to use the full speed range of the motor, but sucks as it’s still running a bit slow.

By moving the belt up one pulley faster, the lathe’s spindle jumps up to around 1260rpm, which is a fair bit higher than ideal, but I can reduce the motor’s top speed on the controller, which hopefully should be sufficient.

Full speed on the second slowest is probably a bit fast, I’ll have to turn the speed limit on to prevent me from burning up the bearings in the lathe.

I’m going to have to use the lathe, and decide whether running the motor at full speed and associated torque is more beneficial than the higher spindle speed. Of course, I can swap between speeds if necessary. I’m hoping to be able to pick a setting to leave it at for most of the time though.

As far as operating everything goes, Basic operations are pretty straight forward. With everything turned on, moving the leaver to the left starts the lathe. Moving it all the way back to the right stops the lathe. I’ve read that some people who use these motors replace the hall effect sensor that controls the speed with a potentiometer, but I really like how this operates. Being able to start and stop with a quick movement feels great to me, so for the time being, I’m going to leave it the way it is.

You can adjust the upper limit of the speed by pressing the green up and down buttons on the motor controller (while the motor isn’t running). You need to delve into the menus further to do things like reversing the direction of rotation, or adjusting the lower limit.

The inability to reverse the motor easily is seen as s negative for some, but I couldn’t do that with the other motor, and as the chuck is just threaded on so I would likely spin the chuck right off if I tried to use it in reverse.

For those who are interested, I’m also attaching a scan of the instruction sheet that came with the motor:

That’s it from me for now. I hope this info is helpful to someone out there thinking of doing similar.

Cheers,
Matt.