rke[pler
Diamond
- Joined
- Feb 19, 2002
- Location
- Peralta, NM USA
I have been restoring the variable speed option on the Autometric Model B I bought late last year (in this thread: https://www.practicalmachinist.com/...-iron/new-k-t-autometric-model-b-user-380896/ ). A previous owner deleted it, I suspect over the cost of repair. When I received the machine it had a 2 sheave input to the gearbox and a matching 2 sheave on the motor, with what I thought was a 7/8" shaft. I replaced the 2 sheave sheave with the appropriate companion sheave for the 1922V by doing what the PO did - they'd shrunk it on after turning down the original sheave, so I pressed it off and put on a companion sheave I'd bored to be a slight interference fit. The other end looked to be a 7/8" shaft so I found a variable speed pulley matching the original from another user (Roto-Cone MS75). When I went to fit it I found that the PO had turned down the motor shaft to 20mm as well as cutting it off so it's now too short.
So I need to either replace the motor - 220V, 204 frame 1.5HP 3 phase 1725. 204 frame is kind of uncommon. Also I'd need one with something like 5" shaft. Unlikely. I might get something in another frame but the mounting pad isn't real deep relative to where the sheave needs to go, and the mounting pad is integral with the tilting and stuff.
Adapt the shaft - 20mm bore on one end to a 7/8" shaft on the other. No fun for the keyways - 1/4 on the remaining shaft but shallow as heck after being turned down from 1" to 20mm. Blind keyway on the adapter if I go integral which I think I should. Doable but ugh, a blind inside keyway.
Finally, just press the shaft from the armature, measure it up and make a new shaft to match but with a 7/8" end about 5" long. Maybe too long for a variable speed pulley adjusted by belt pressure on 7/8? I could go up to 1" but that would require replacing the 7/8 MS75 with one needed a 1" shaft.
Thoughts? Kinda leaning towards #2 since that's the least work. But if I need a 1" shaft for that length #3 would likely be the way to go.
So I need to either replace the motor - 220V, 204 frame 1.5HP 3 phase 1725. 204 frame is kind of uncommon. Also I'd need one with something like 5" shaft. Unlikely. I might get something in another frame but the mounting pad isn't real deep relative to where the sheave needs to go, and the mounting pad is integral with the tilting and stuff.
Adapt the shaft - 20mm bore on one end to a 7/8" shaft on the other. No fun for the keyways - 1/4 on the remaining shaft but shallow as heck after being turned down from 1" to 20mm. Blind keyway on the adapter if I go integral which I think I should. Doable but ugh, a blind inside keyway.
Finally, just press the shaft from the armature, measure it up and make a new shaft to match but with a 7/8" end about 5" long. Maybe too long for a variable speed pulley adjusted by belt pressure on 7/8? I could go up to 1" but that would require replacing the 7/8 MS75 with one needed a 1" shaft.
Thoughts? Kinda leaning towards #2 since that's the least work. But if I need a 1" shaft for that length #3 would likely be the way to go.