- Joined
- Dec 4, 2016
- Messages
- 9
Underdrive trouble
Hi folks
I've got about 10 hrs runtime on my new to me SB 14.5" x 6'. Overall it's in fair shape considering it's age and I'm addressing issues as they come up.
I've got the underdrive all apart because the flatbelt recently started running off on startup. Investigation shows the nondrive end of the conepully shaft has worn the cast iron bearing area oblong and the shaft is worn about .015" and scored on both fits.
I suspect one side is worse because it's the side the flatbelt tensioner is on.
It looks like I may be the first to atempt this repair on this lathe but the underdrive has obviously been apart a few times in the past and someone converted the lubrication to grease which lead to a massive amount of cleanup.
I'm considering options but a trip to a pro shop for lineboring may be a good start. The shaft is pretty simple and 1.250" dia so replacing it is likely within my budget . The setscrew dimples for the conepully and collar that positions the shaft are no problem but I don't have tapered pin reamers yet for the hole that locates the flywheel/ vbelt pulley.
The videos I've seen all show a ball bearing setup but this one is older than those and the shaft runs through 4 cast iron fits that I think originally had wick oil lubrication. I've been unable to find much info online about this setup and modification to antifriction bearings would likely be impractical
I think lineboring to at least 1.5" is possible then if I install bronze bushings and ream them to size I'd be close to original.
I'm concerned that once everything is reinstalled it runs longer than I do. I can't foresee me taking it apart again in 10 or 15 years and time is not a big issue so I'm taking the motor to a shop to be refurbished and will work away to repair and then paint the underdrive
Any suggestions or info ?
Mike
Hi folks
I've got about 10 hrs runtime on my new to me SB 14.5" x 6'. Overall it's in fair shape considering it's age and I'm addressing issues as they come up.
I've got the underdrive all apart because the flatbelt recently started running off on startup. Investigation shows the nondrive end of the conepully shaft has worn the cast iron bearing area oblong and the shaft is worn about .015" and scored on both fits.
I suspect one side is worse because it's the side the flatbelt tensioner is on.
It looks like I may be the first to atempt this repair on this lathe but the underdrive has obviously been apart a few times in the past and someone converted the lubrication to grease which lead to a massive amount of cleanup.
I'm considering options but a trip to a pro shop for lineboring may be a good start. The shaft is pretty simple and 1.250" dia so replacing it is likely within my budget . The setscrew dimples for the conepully and collar that positions the shaft are no problem but I don't have tapered pin reamers yet for the hole that locates the flywheel/ vbelt pulley.
The videos I've seen all show a ball bearing setup but this one is older than those and the shaft runs through 4 cast iron fits that I think originally had wick oil lubrication. I've been unable to find much info online about this setup and modification to antifriction bearings would likely be impractical
I think lineboring to at least 1.5" is possible then if I install bronze bushings and ream them to size I'd be close to original.
I'm concerned that once everything is reinstalled it runs longer than I do. I can't foresee me taking it apart again in 10 or 15 years and time is not a big issue so I'm taking the motor to a shop to be refurbished and will work away to repair and then paint the underdrive
Any suggestions or info ?
Mike
