Shopsmith Forums

I'm rebuilding my motor as it wasn't starting up and was throwing my breaker. Everything seems ok electrically (no short to chassis, switches work ok, 0 ohms between leads) but both bearings were bad/hard to turn so I assumed that was the issue. Otherwise it looks pretty clean aside from this one part (see below). One of the white plastic pieces on this part is a little torn up. Honestly I don't know how this thing works but believe it is the capacitor switch (could be totally wrong).

Big question: is this part ok to use as is? Should I trim up the jagged plastic with a razor knife? Or do I need to replace? I wasn't able to find just this part on either Ebay or Shopsmith website.

Looks like a badly beat up start switch.

Here is a link to a thread about the start switch. I posted my experience with my GE 1-1/8 hp motor, and your part looks very similar to mine.

viewtopic.php?f=10&t=23758

Yes that is at least the actuator and one of the contacts(I do not see the other contact)

I fear the worn white plastic part is the reason the contacts were not closing ab=njd that was causing the breaker tripping.

There appears to be other melting of black parts as well, but I think that is actually an elastic substance that provides a dampened pivot for the fingers and contact.

I would look closely at the fly weighted actuator ring that apparently was failing to move completely off the white plastic part once the motor got started.

Yes the plastic part must be 'fixed'. Interesting shape of the non damaged one which also shows sign of wear.

I would consider replacing both.

Just to confirm I understand how this works: when the motor is not rotating, the white plastic pads (worn in my case) on the start switch, are pushed up by the black disk, *opening* the contacts on the switch. Once the motor starts rotating, centrifugal force cases the black disk to descend, allowing the white plastic pads to descend as well, closing the contacts (aluminum arms come into contact with copper wishbone on both sides). There is some sealed magic on this version (why you can't see the main contact like in the linked images).

Anyway, the key takeaway is that the white pads should only be rubbing on the black disk for a tiny amount of time when starting up. So the fact that they are worn means one of: this thing has been started up many times, the black disk isn't descending fully as it should, or the start switch is bent/misaligned so that it is always in contact, even after the black disk has descended.

The black disk, lowered by centrifugal force, moves pretty nicely and easily although I dont' have a sense for how easy it should be. So, I'm inclined to think things would start working if I just replaced the white pad, but unfortunately I don't see how to do that (riveted to the copper wishbone) so I think I should just try replacing the whole switch.

https://photos.app.goo.gl/hVmHBWVSf35y2XKZ9 (video of centrifugal switch, seem ok?)

Anyone know where I can find one? I was considering messaging all the people on Ebay doing motor rebuilds, hoping they have one in a bin somewhere.

The best and easiest place to look for a replacement centrifugal switch like that is your local electric motor repair shops. Ebay is useless to repair motors. Your skilled local repairmen are worth their weight in gold.

I found one! I emailed a few people who did repairs and someone had exactly this part laying around. Now crossing my fingers that is the root issue and not just a symptom.

Glad you found one!!! The fly weight mechanism looks normal in yer video.

I got the new part, put the motor back together and everything ran great! Then I reinstalled the shivs and spring, reattached the bottom headstock pan to the motor, and reattached the motor to the headstock and belt. So far so good. The entire assembled headstock ran and sounded great for about 3 seconds, then there was a loud pop and the spring, washer and retaining clip shot across the room. Luckily I wasn't in the way.

I think the culprit is the retainer ring which honestly didn't look very secure to me when I put it on. It was straight and looked like it was aligned with the groove at the end of the motor shaft but just didn't look deeply seated in that groove, as if it wasn't tight enough. It may be that when I took it off it got deformed? I'm not sure. (does look a little wonky in the picture).

Any thoughts on this? I could put it back on and maybe squeeze with pliers to make it seat more deeply, and just try again. Or is this a wear part I should replace? I did order a new one from Shopsmith but they are very slow. Another alternative is I could just by another one locally. Any ideas what sort of place has a selection of snap rings where I could get the right one?

Thanks

Good luck finding one at a hardware store. I would put the squeeze on it and reinstall. A good retaining ring pliers is really almost necessary to prevent opening them too far.(especially this type)

eagspoo wrote: ↑Thu May 06, 2021 1:09 pm Any thoughts on this? I could put it back on and maybe squeeze with pliers to make it seat more deeply, and just try again. Or is this a wear part I should replace? I did order a new one from Shopsmith but they are very slow. Another alternative is I could just by another one locally. Any ideas what sort of place has a selection of snap rings where I could get the right one?

Snap rings can be over-extended during removal and lose their strength. Seems more common on small ones like the worm gear shaft. Standard is that they are sized by shaft diameter. This is a special type but not rare, if I think about other things the name may come to me. I've bought this exact one at Fastenal in the past, they offer shipping and many areas have a local store. They have a really good shipping policy if you pick up in store, they are very fast and it costs pennies. They are my go-to on several things. Not necessarily better than some of the big catalogs, but they are local everywhere around here.

- David