Mr Bridgeport
Stainless
- Joined
- Nov 27, 2002
- Location
- Burlington, NJ
I'm involved in a job where I have to replace the spindle bearings in a TOS SN40-C engine lathe. I have worked on many lathes before but this one is a strange beast. The headstock is a two piece afair with the backend being the transmission and the front end housing the spindle. From the looks of the parts manual it looks as if there is a splined or keyed connection between the transmission and the spindle.
I called TOS and the parts guy said that you unbolt the transmission and slide the headstock forward on the ways. From my examination of the assembly, it looks as if I have to remove the gearbox to get at the bolts holding the back of the spindle housing to the bed. That gearbox looks heavy and there is no provision for lifting bolts. This looks to be a major PITA.
The spindle bearing set up is strange as well. On the front of the spindle is a double row roller bearing (not a Timkin tapered bearing, straight rollers here) designed to take the radial load and at the rear end of the spindle is a duplex bearing to take the axial load. I would imagine that the duplex bearings are factory preloaded and need no further adjustment. The front bearing sits on a taper and the bearings have a matching taper in the ID as well. There is a shim spacer between the bearing and the shoulder on the spindle. Giant hug nuts hold this all together. I'm thinking I may have to mess with this shim to set the radial play to some nominal amount, like maybe 0.0002 or so. Kind of like on a Deckel milling spindle.
Has anybody done this before? Any tricks or short cuts to help out here? I love it when a manufactor comes up with a "better idea" and makes it so darn complex. I have quite a few TOS lathes in my service area and have worked on a few but never in the headstock. Thanks in advance.
Bill
I called TOS and the parts guy said that you unbolt the transmission and slide the headstock forward on the ways. From my examination of the assembly, it looks as if I have to remove the gearbox to get at the bolts holding the back of the spindle housing to the bed. That gearbox looks heavy and there is no provision for lifting bolts. This looks to be a major PITA.
The spindle bearing set up is strange as well. On the front of the spindle is a double row roller bearing (not a Timkin tapered bearing, straight rollers here) designed to take the radial load and at the rear end of the spindle is a duplex bearing to take the axial load. I would imagine that the duplex bearings are factory preloaded and need no further adjustment. The front bearing sits on a taper and the bearings have a matching taper in the ID as well. There is a shim spacer between the bearing and the shoulder on the spindle. Giant hug nuts hold this all together. I'm thinking I may have to mess with this shim to set the radial play to some nominal amount, like maybe 0.0002 or so. Kind of like on a Deckel milling spindle.
Has anybody done this before? Any tricks or short cuts to help out here? I love it when a manufactor comes up with a "better idea" and makes it so darn complex. I have quite a few TOS lathes in my service area and have worked on a few but never in the headstock. Thanks in advance.
Bill