Oil leak at spindle on my lathe

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RSG
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Re: Oil leak at spindle on my lathe

Postby RSG » Fri Jun 16, 2017 4:23 pm

spro wrote:I would attach a stiff wire to a strong small magnet and wick it around in there.


Good trick Spro, I used a telescopic magnet and pulled up all kinds of shavings....
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RSG
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Re: Oil leak at spindle on my lathe

Postby RSG » Fri Jun 16, 2017 4:24 pm

SteveHGraham wrote:Man. It's disturbing that someone would give you oil he wasn't sure about.

Tell me about it. I wasn't too happy with him. He must not give a crap about his machines...or maybe just mine!
Vision is not seeing things as they are, but as they will be.

RSG
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Re: Oil leak at spindle on my lathe

Postby RSG » Fri Jun 16, 2017 4:37 pm

John Hasler wrote: What with the headstock heating up and silvery stuff in the oil I guess I'd seriously consider tearing it down for an inspection.


I just did a high level inspection now! Here is a pic of the gear selection I use most. To my untrained eye they don't look too worn. A little rough on the sides but the flank and face look good. Pic attached might not be that good for viewing but I added it anyway. The little white flecks are just paper towel lint.

What are your thoughts?

Image
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SteveHGraham
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Re: Oil leak at spindle on my lathe

Postby SteveHGraham » Fri Jun 16, 2017 5:15 pm

Those gears look machined, not worn, except for what looks like some grinding due to missed gear changes. Hope that is the case. Are you sure you didn't flub some changes? I would think a gear that was wearing due to an oil problem would have wear on the faces of the teeth.

Also wondering if the oil your good friend gave you leaked because of its composition. I don't know if it's true, but people say synthetic oils will leak through seals that held conventional oils just fine.
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John Evans
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Re: Oil leak at spindle on my lathe

Postby John Evans » Fri Jun 16, 2017 6:16 pm

Maybe the oil you were given was automotive detergent type and that is why metalics were in the oil. Having a small strong magnet in the bottom of the HS is a good idea.

spro
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Re: Oil leak at spindle on my lathe

Postby spro » Fri Jun 16, 2017 6:34 pm

I especially agree now. It wouldn't be too bad if the gears were merely lapping in but the excess leakage from the bearings, invites something worse. You already know where I'm going and it isn't pleasant.

spro
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Re: Oil leak at spindle on my lathe

Postby spro » Fri Jun 16, 2017 6:54 pm

I cannot say this is an example of thin oil but the teeth are fair rough surfaced. It was going to happen anyway but maybe not get into the head bearings. As pita they would be to replace, could be done and not maybe not now. It would be on my list and the worse thing is seizing. Hot and hot, perhaps leads to seize which then spins the bearing race in the casting or retainer or over the spindle. That's a major pain which I hope you won't face in 20 years. At this point, the bearing seal leak will be good while the new clean oil flushes out the bearing.

spro
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Re: Oil leak at spindle on my lathe

Postby spro » Sat Jun 17, 2017 12:43 am

FWIW, I have an older Tai 12X36 without the gap bed. The headstock is composed of many drive type, belt then gears to the head or belt to the head. They all take different lube or none at all. It isn't near as good as a gear head but gear grease doesn't penetrate the headstock bearings. When it all went to gear head, cool but I remember cleaning the grease from the helical gears. There was evidence of lapping going on there. This was the backshaft and that could be adjusted by eccentric bearing mounts which take oil. The belt, of course, wanted neither but survives. I do not know about gear heads which have adjustable shafts which reduce play. It is either the bearings ,gears or shafts need replacement.
From what I saw (which wasn't terrible for those gears) I wouldn't wanted any of this run-in getting into the main bearings.
There are excellent gear heads as there are superb transmissions. Is the question "viscosity" ?

spro
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Re: Oil leak at spindle on my lathe

Postby spro » Sat Jun 17, 2017 2:32 am

Digging my own hole here because of what posted earlier. The bearings had their own lubrication. The inner seal may have been penetrated but don't know that. Something mentioned before about foaming, non foaming or the heat. There would be a vent atop the head to allow the pressure to vent out before it penetrated sealed bearings.

pete
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Re: Oil leak at spindle on my lathe

Postby pete » Sat Jun 17, 2017 7:26 pm

It's impossible to be 100% sure of correctly diagnosing a problem like you seem to be having with your headstock on a forum. But it's obvious somethings not right. Metal flakes in the last oil have to be coming from somewhere. And warmer than usual for the headstock while running doesn't sound good. I'd add a small strong magnet somewhere in the base of that sump out of the path of any of the gears with an oil change to the correct weight and level of oil and check the magnet after a few hours of running. And depends how many corners were cut while that lathe was being built. Yes it should have a vent. It might not since I've read a few posts where others have said there Asian built machine didn't have one. Might even be plugged if there is one. With a plugged or missing vent then the seeminly new heat build up would tend to help force the oil through the bearings resulting in a leak. Metal flakes won't do the spindle bearings any good that's for sure. Your gears were almost for sure hobbed but not ground or probably heat treated after by the looks of the one picture. It's not impossible one of the lower hard to see gears is going, but if a gear is getting chewed up I'd expect to hear some additional noise from that. Try various gear combinations while running to see if one's a lot noiser than the rest.

I don't know of any lathes with a geared headstock that don't use either bronze sleeve bearings or some type of rolling bearing for the shaft bearings. Bronze wouldn't leave the silver color. Are you 100% sure the oil you used wasn't contaminated in some way. Dirty container etc? A 10 wt non detergent oil shouldn't be enough of a difference to cause parts to fail that quickly. My lathe takes what's listed as 20 wt. spindle oil. I've got gallons extra, but if I had to I wouldn't hesitate to use 10 weight non detergent if that's all I had at the time. I'd change once I did get the correct weight of course. Over filling a gear box can result in some extra heat and that could be part of the reason for that leak. I'd put an indicator on the front of the spindle and try pushing it back and forth and check the endplay, then do the same by putting the indicator tip on the top of the spindles nose and try prying the spindle up with a piece of 2" X 4" to check the bearing clearance. If you've got enough metal flakes from that lathes internals to change the color of the oil then if it really is the bearings it will show up as excessive bearing clearance by now.

It also might be worth draining the oil and wash and clean out the internals and especialy the bottom of the sump with diesel, then refill the gear box to the normal fill level with fresh diesel and run it at a medium speed for about 5 minutes. That will flush out any contamination or metal flakes in the box and especially from the bearings. Drain all that off then refill with the proper oil. At best all I can guess at is pre contaminated oil, or the oil you used was a high detergent oil that allowed any junk laying in the bottom of that sump to cycle through the gears and bearings. But the tooth faces of those gears in your picture still look ok.

RSG
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Re: Oil leak at spindle on my lathe

Postby RSG » Sun Jun 18, 2017 8:15 am

Pete - to answer your question regarding possible contamination prior to filling with new oil the answer is no, the oil was clean, it did however turn out to be 10wt (or so my friend thinks from the container he gave me). You also mention overheating and oil leaks due to possible over filling. It's worth noting that I had twice the recommended amount of oil from the last change. Since there is no documentation in the manual regarding correct volume I just added what I thought was the right amount. Thinking back to the oil change I did in January I remember the sight glass showed the correct level at fill time but later must have corrected itself once the oil got warm and displaced the air bubble inside because a while later it showed over full. I didn't bother to remove oil thinking that more was better than less. Guess that was wrong.

This lathe does have a vent at the top but the plastic screw cap was on tight since I never used it to fill the oil. I cleaned all the oil and metal particles out with a magnet and refilled the head stock with 3.5 liters of the proper oil Friday. Since then the headstock barely feels warm. The odd sounding gear noise I was hearing for the last few months was gone too.

I'm glad most agree the gears in my pic don't appear too worn. This has been a less learned and I won't repeat the mistake. I appreciate everyone's input. I'll do those spindle tests over the next day or so.

Ron
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pete
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Re: Oil leak at spindle on my lathe

Postby pete » Sun Jun 18, 2017 4:25 pm

Do you have any specifications in your lathe manual on what the spindle end play and bearing clearances should be? Your measurements on what you now have may give a good indication on the condition or if any adjustments might be needed. But I'm a very long ways from knowing much about high precision spindle bearings or even the best methods of properly adjusting them. One indicator without doing any tests would be the surface finish your getting compared to a few years ago. Any changes in that?

It's still a best guess on my part, but if I had to bet I'd say the extra heat, sealed off vent and then having that oil leak was just from having the level too high. In a gearbox I've never heard of any real mechanical damage from having them overfilled other than possible seal damage. You might have gotten lucky. Those metal particles would have me a bit on edge though. I think I'd be keeping a close eye on it for awhile. As someone else mention the last thing you want to happen is have a bearing spin in the bearing bore. Replacing spindle bearings is expensive enough without having to rebore the headstock oversize, sleeve and then rebore for the precision fit required. I know just enough to understand it's pretty touchy work and maybe outside the capabilities of most of us with home shops.

Your picture shows just a partial view of the headstocks internals. It could be just a simple splash oiling system. Are there any oil lines? If there are that would indicate it having a pump as well. I'd also check if that's properly working with the top cover off and the lathe running at a very slow rpm. High speed will throw oil everywhere with that top cover off. That's about all I can think of.


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