Oil disappearing on my SB9

bll230 · Mar 11, 2009

I do not think I have had to fill the front bearing reservoir more than twice in 2 years, but I have to fill the rear reservoir every day. The oil seems to be drawn out the rear by capillary action of the needle roller bearing I have between the adjustable lockring and the headstock casting.

The evidence for this theory is the paper towel I tie around the lockring very quickly becomes saturated with oil.

I am using the Mobil spindle oil per Webb.

Any thoughts, or is this just one of the things you live with on a 60 year old piece of machinery.

Thanks

John Benario

plastikosmd · Mar 11, 2009

I would be more worried about the front not using oil? I top mine off before each use..never bothered to check how much gets used. Good question

bentwrench · Mar 11, 2009

I had a similar problem. My front bearing would take a drop every now and then, while the rear bearing would empty the resvior in about 15 minutes. My bearings had the correct clearence and the return holes were clean. I 2replaced the felts and cleaned everything out the best I could. The problem went away. SO it was either the old felt casuing the problem or the return holes were obstructed with dirt and I didn't get them clean the first time I took it apart. Now I add a couple of drps every time I start it up, it runs for hours without draining down much at all. They do recirculate the oil but you can't expect 100%, there will be some loss of oil. Anyway that was my experience.

bll230 · Mar 11, 2009

Bentwrench, maybe you have something here. I completely rebuilt my lathe and put new felt everywhere, and I thought I was completely familiar with it, but the return holes you mention are new to me. Where are these return holes?

After hearing from you I will take it apart and check them.

Thanks

John

bentwrench · Mar 11, 2009

Here is a good picture of the return hole...

http://www.practicalmachinist.com/vb/showpost.php?p=591373&postcount=11

Here is the entire thread on 9" spinlde oil;ers and wicks, a must read if you own one of these lathes.

http://www.practicalmachinist.com/vb/showthread.php?t=129331

bll230 · Mar 11, 2009

Got it thanks. I am leaving for a model helicopter event tomorrow, but when I get back I'll take the spindle out and see.

John

bigmac · Mar 11, 2009

I don't know if the 9" lathe is like the heavy 10", but the spindle info downloaded from the swells site states that the bearing will throw oil if the vent holes are plugged. These are tiny holes located above the spindle oil cups (on a 10", anyway). Hope this helps.

scott miller · Mar 12, 2009

I have a steel ground washer between the lockring and headstock casting.

Is your roller bearing a modification?

Scott

bentwrench · Mar 12, 2009

The factory part on the 9" lathes is actually a fiber thrust washer, but a number of people have used a very thin roller bearing in place of the fiber washer. It's a common part from McMaster-Carr, if you search you can find a few posts on that subject as well.

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