left side transmission bearing

[inrustwetrust]

Just recently discovered that the unobtainable left side 207 thrust bearing is the same as the spindle bearing 207 IW in the bridgeport milling machine. It is a different bearing that a bearing shop would refer you to as a replacement, which is not suitable. The bad news is the price.

[koanes]

Inrust, maybe you can tell me if I replaced the bearings in my milling machine correctly. I mounted the bearings back to back in the spindle, thrust side facing out from the center spacers. I just can't wrap my head around this one. The bottom nut that threads into the quill pushes against the thrust face of the outer race and seems very sensitive. If I tighten the bottom nut just a tiny bit much, the spindle is hard to turn. What determines the load on the top bearing? Just the spacer on the spindle between the top lower bearing and the top spindle bearing? I would appreciate any help you could offer. Thanks, Kyle

[inrustwetrust]

I would like to hear from people with more experience also. I put the bearings back as they came out, thrust face to thrust face. The nut was tightened as it was undone, not quite snug, but not loose.... better than hand tight.
Thanks

[koanes]

I will get in touch with someone that has done this professionaly. When I took my machine apart, both bearings had the thrust face pointed towards the bed. I had a lot of spindle run out and assumed it had been assembled incorrectly. Hard to find a repair manual, all I can locate are parts drawings with maintenance intructions. I'll share the info when I get it.

[koanes]

Inrust, I sent you an email with the info I gathered.

[indianut]

Kyle, this may help.

http://www.practicalmachinist.com/vb...d.php?t=175364

[koanes]

Thanks Danny, I managed to find my way thru the job OK. Had the bearing seal at the bottom of the spindle in upside down (was assembles this way when I got the machine, with the bearings installed incorrectly, it didn't seem to matter) so I got to do it twice. I took a couple of heavy 5" radius flycuts after I got it right and never got a smoother cut on anyones machine. Yee Haw!