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Leaky Spindle

MatthewL

Plastic
Joined
Jun 27, 2018
Location
Houston
I have a South Bend 9C (plain bearings). I have had the lathe for probably about a year now, and since putting it back together after cleaning and repainting it, the back gits oiler seems to loose oil much more quickly than the front oiler. However, I have no idea where the oil goes so quickly. I never see any oil leak from around the spindle. It has run just fine over the year I have had it. Anyway, just to see if I could fix the problem, I removed the spindle. I didn't notice anything odd, so I reassembled the headstock. But now, when I try and turn the spindle by hand it gives more resistance. Before, I could spin the chuck by hand and would move for about one rotation, but now when I spin it, it stops much quicker. Also, both oilers loose oil very fast now, and I see oil coming from up underneath the cone pulley and puddling on the ways. I didn't change anything, so I have no idea what is accounting for this problem. Does anybody have any ideas?

Thanks,
Matthew
 
it could be anything from dropping a shim and not noticing, cleaning out ancient grime that was forming a seal on the spindle or adding a few thou between shims. The resistance tells me you probably have the bearings too tight or there's some other sort of misalignment. Can you use a test bar and see if there's any play when you try and pull up on the spindle? Is there take-up nuts on the end of the spindle? You need a small amount of endplay to allow for clearance for oil to get around everything. It's easy to overtighten them or you may not know that you don't want to put the hand of God on them. I'm not sure about the plain bearing headstock design, I've only owned versions with Bronze bushings, the construction could be very different.
 
The spindle still has resistance even if I completely loosen the take-up nut and the screws that tighten the bearings. I thought originally some of the felt from the oil wick got might have gotten caught between the bearing and spindle, but I was really careful to clean the bearing and spindle before putting it back together. And now with all the oil leaking out, I am really not sure what happened.
 
It seems the spindle has lost the resistance it had. Again, not sure why. I took about ten thou off a steel bar for a project I am working on, and the spindle seems to have lost most or all of the resistance it had. However, oil loss is still terrible. In about ten minutes (running for a few of those minutes), both oil cups completely drained and the oil was coming out and puddling on the ways. I am not exactly sure where all the oil is leaking from. There is some oil under the cone pulley and it seems there is some oil coming out of the small holes above the oil cups.
 
It may be that the drains are not working.You have oil coming up by the wicks, but not returning through the drain passages.It just overflows onto the outter surfaces of the headstock casting. Its not getting back to the reservoirs.Your return passages are not functional.They could have been fowled with dirt, or the little wires that live in them may have been lost.
Try cleaning the reservoirs out by pumping solvent or kerosene into the oilers until the solvent runs clear out of the bearings. Use a pump oiler.
Remove the oilers and let the reservoirs drain.When the solvent stopps running out,put the oilers back in and fill the reservoirs again.Check the clearances at both ends and see if the spindle is free.
If it is OK start the machine and see whats going on.This is my version of a routine maintenance procedure from an old SBL book.
The little wires I mentioned are a deeper issue and nobody seems to really know about them.I have read things that said they break surface tention that can interfere with the draining.
 
Make sure the bull gear is fully seated....weird stuff can happen.

BTW- it's kind of a normal occurrence for the small end to use more oil,as was explained to me it has to do with the increased SFM and oil "whip" (can't remember if that's the right terminology) but as long as it's not excessive and there's no overheating don't worry about it.
 








 
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