Shopsmith Forums

Just got my first Shopsmith from craigslist. It's a Mark V according to manual. I got a good price because the thing was making a grinding noise. I figured it worth it to try and fix. So here's what I did...
The lower pulley was making a metal on metal sort-of grinding, screeching noise. Not super loud but enough to notice something wrong with it. When hand turned (no power) same thing, like the pulley was hitting something?
So, I removed the drive belt (the lower v-belt, not the flat one higher up) and tested power to motor, and the motor sounded flawless. Smooth and no noise. Sounds very good surprisingly.
I inspected the belt and it is a little worn and roughed up.
So, the question is, I was gonna buy a new belt, assuming it needs one at this point in it's life. I just dont wanna install it and ruin it only to find it wasn't the belt.
Is there anything I should be checking as to why it was making that noise? The upper assembly seems to be working right...no noises, smooth turning. And motor when no belt is on sounds great. just when the belt was on...
Also, if you can, jut explain to me how the pulley system works? Im guessing the spring-loaded pulleys add tension to control speed or power to accessories?
I must sound like a newbie. lol. so looking forward to learning more about how these machines work. I'll be honest, I got it cause I "needed" (i.e wanted) a lathe, but half of me wanted it because its just so cool looking.

First posting, and I plan to detail this later on boards, but I just restored my shopsmith last week and it had similar sounds from the same area. I had to pull the sheaves off the motor shaft as they were bound together due to sitting for so long. I also had to file the key that keeps them in place just a hair as that seemed to be what both were ultimately glued to. It wouldn't be a horrible idea to pull apart the head stock and clean all the parts and lube it all back up.

Thanks I’ll try those ideas and let you know how I make out. Thanks for your time in replying. Appreciate all the advice.

Take the fan pulley completely off while you are in there. Behind it there is (or likely should be) a slip on spacer between it and the motor. It can wear and reduce the space to keep the back from scraping.

Take a look at the setscrew indentation where it locks down and clean it up to smooth it out. That will help you put it back and get it secured in the right place.

Look at some of the exploded parts listings for more info.

Everett

So something I missed entirely first go round, the access to the set for the motor sheave is found at the very bottom of the motor tray. And I cannot recall the size on it but it wasn't the same as the ones to disconnect all the tools for the SS. You'll need to either remove the motor from the tray OR find a very long allen wrench that matches.

everettdavis wrote:Take the fan pulley completely off while you are in there. Behind it there is (or likely should be) a slip on spacer between it and the motor. It can wear and reduce the space to keep the back from scraping.

Take a look at the setscrew indentation where it locks down and clean it up to smooth it out. That will help you put it back and get it secured in the right place.

Look at some of the exploded parts listings for more info.

Everett

This might help Everett

Assuming it is the fan sheave rubbing, the spacer has a habit of embedding itself into the softer sheave. My suggestion(cheaper than a new fan sheave) is to slip a retaining ring between the spacer and the sheave.

As for how it works, the control process begins with the speed control knob. Rotating the knob causes the quadrant gear(porkchop) to move the control sheave towards/away from the idler sheave. Those two sheaves are the halves of the idler pulley. By moving the control sheave, the effective working diameter of the idler puller is changed. When that occurs, the motor belt tension is changed. The pulley on the motor shaft consists of the fan sheave(fixed) and the floating sheave(moves). When the belt tension changes due to the control sheave moving, the spring loaded floating sheave moves to compensate and maintain belt tension(both to increase tension when the control sheave opens the idler pulley AND to decrease it when the control sheave closes the idler pulley). The movable sheaves(control/floating) move in opposite direction(one opens as the other closes and vice versa).

The movement of the control knob towards slow causes the control sheave to squeeze the belt. The floating sheave must move to open the motor pulley in response. If the floating sheave is slow to respond(gunked up) or the control knob is adjusted too rapidly, the quadrant gear can become damaged. That is the reason for the "DO NOT ADJUST SPEED UNLESS MOTOR IS RUNNING" warning. Also IF the floating sheave is slow to respond when adjusting the control knob towards fast, the anti-rotation clip attached to the bearing in the end of the control sheave may get pulled apart.

Moral: keep both movable sheaves well lubricated!!!

In addition to JPG's explanation above this may help

Everett

Wow! That is very helpful Everett. Thank you.