Looking to replace the lathe and mill bearings

[bprager]

Got the spindle put on the lathe head and all the bearings off.
Couple of quick questions:

1)The lathe bearings are inside the oil seals (felt rear, rubber front) so do I oil the new bearings? Using grease would just seem to mix grease with the oil as the splash lub runs?
2)Do I heat up the new bearings before putting them on, and if so, just just a hot air gun? Thats what I was thinking of doing - around 180 deg or so.
3)How do you recommend pressing on the front bearing?
4)Due you use the rear threaded nut to set the rear bearing as the spindle has to be in place before it goes on. Any way to know how much to tighten?
5)Last, Where can I get new oil seals for the front and rear of the spindle? The rear is just felt and I can get that OK, but the front appears to be a special rubber seal and its ripped, I think from day one. Couldn't figure out where to get one (and what to ask for) and the best way to remove and replace it.

I got great instructions from you experts on R&Ring the Mill. If someone can help me out on the Lathe, I think I have a good handle on getting the guy up and in good running order.

Thanks in advance for all your help!!

Bruce Prager

[digitalmdj]

Which machine do yo have. My tripower didn't have a front seal. The rear is felt. You can buy square felt from california rubber. The bearings are greased . To install the inner race you need to heat the inner race of the front bearing to about 210 to 230 degrees and it will just slide right on. Then grease the front bearing with quality bearing grease. Then tap the front inner race into the clean housing. Anything left in the housing will affect the runout of the spindle. Then tap in the rear outer race into the housing. Then grease the rear inner race. Now you should be ready for assembly. slide the shaft into the housing. Then slide on the rear inner race and tap it onto the shaft. I have a long bearing installer that was custom made to do this so you will have to figure that part out. It should tap on and should be tight. Then install the rest of the parts.

[smallblock]

Bruce,
I use the old school method of first packing the bearing and then pressing it on to the shaft in a bearing press. The rear bearing is lighter fit, and can be tapped into place using a piece of pipe that will fit over the shaft and against the inner race. The front seal should be a 45 ID X 62 OD X 12 Thick according to my manual. If you are getting your stuff at a bearing supply house they should be able to supply that as well. Don't forget to slide that seal and seal plate over the spindle before you press the bearing on- been there-done that.

[dahui]

I have a bearing replacement on my site (with Timken part #s). Didn't take that many pictures but it's pretty self explanatory. Dissasemble, take old bearings off, put new bearings on, reasemble. I didn't use high precision bearings as I didn't really feel this was a high precision machine.

There is also some debate over the splash lube on the lathe spindle. First, my machine doesn't have any kind of seals on the lathe. Second, it's the same as the mill spindle, which runs at much higher RPM and is only grease lubricated. I packed my lathe bearings full of grease and decided not to worry about it. In fact, I pulled out the whole tripple gear thingy from the gearbox and I'm running dry. I don't do any threading so why have all those gears turning all the time, wearing out and creating vibrations that affect my surface finish? Runs like a dream. If I ever want to thread it's about a five minute job to put the gears back in.

[sharpshooter90]

Dahui,
We did the same thing on our servo unit. We changed out the spindle bearings and just removed the drive gear from the spindle and left the other stuff inside. Our servo system had the CNC threading capability, so there was really no need for the gear train to be active.