Oil leak at spindle on my lathe

[RSG]

This may sound like a dumb question but does a spindle have a gasket or seal? The reason I ask is I noticed last night that it was dripping head stock oil and left a pool down in the gap bed. I have never noticed this before so I investigated by taking the top off the head and having a look inside. I couldn't really see anything though. I did notice the oil is up higher than I thought I set it judging by the site glass. Is it safe to assume it's just spilling over or is this something I should address.

Thanks

[TomB]

Mine is a 3-in-1 machine and it leaks oil out of both ends of the lathe spindle. I sure there must be a way to take the spindle apart and repair the seals, but I just put a paper towel where it drips and add more oil when it it too low in the sight gauge. I suspect the mill head has a similar seal with actual oil above the seal but it does not leak.

[John Evans]

Most do not use a lip type seal , rather a labyrinth type .Too heavy a oil or over filling will cause leaks,also a oil that does not have anti-foaming additives can cause leaks.

[RSG]

Thanks for the reply guys. The oil is a lathe oil, I just don't know what viscosity since I got it from a machine shop friend. I have new oil that I am going to put in shortly and it's EP68 as recommended by the manufacturer. I won't put so much in this time either.

One thing I noticed is I changed the oil back in January and when I pulled the cover off last night the oil had a strong metallic silver look to it like I've never seen before. I've used the lathe hard since changing the oil but I don't think I've ever noticed it this full of metallic particulate after even a year in the past. Does this seem right or is it wearing fast?

[Harold_V]

Does this seem right or is it wearing fast?

I expect something isn't right. If the oil you used wasn't the recommended spec, that may be the reason.
Keep in mind, metal in the oil represents metal lost from bearings as well as gear faces. It's called wear. You may have reduced the useful life of the components. Hard to say, but it will reveal itself in the future if you have. If it runs without issue for several years, likely not much to worry about. It's hard to predict.

H

[RSG]

Thanks Harold,

I sure hope I haven't ruined anything. I listened to my machinist friend that sold me the oil and he was rather caviler about it saying head stock oil is headstock oil...... Since I ran out of that oil I contacted the lathe manufacturer and asked what the proper oil is and bought 5 gallons. I plan to change it this week and will monitor it over the next few months.

[BadDog]

That would certainly have me worried. You don't say what type of lathe (and I don't recall), though it clearly has an oil bath head stock. And with a decent quality lathe (or gearbox of any kind) I can't imagine it would produce what (as I see it) you described even if running in a production environment. However, I have heard/read people report such things during the early life of bargain basement imports, presumably from running in the gears/collars (one would hope not from bearings). I've also heard of cheap imports releasing sand from the casting into the oil. So if this was the break-in oil, maybe not so concerning. But something all new lathe owners (particularly budget/hobby lathes) need to remember is to change that break-in oil.

Another thing comes to mind. All but the very high end lathes use splash oiling rather than pumped, and even those that pump usually don't have filters. Which all goes to say that your spindle oil should be a suitable non-foaming non-detergent oil of the indicated weight. Detergent oil is used when you want to keep particles in suspension to be captured by a filter. Otherwise you want the particles to fall out and not get endlessly thrown back onto critical surfaces to produce accelerated wear. So if it was detergent, not only would it accelerate wear, but it would hold those particles in suspension, I expect producing what you describe.

When I got my current lathe, it came out of a production shop where it saw duty as a giant "tool room" lathe (producing tooling for a huge CNC shop). So not hammered like a production lathe, but used a lot more than a typical hobby lathe. No idea how long the oil had been in there, but it looked clean. It looked well cared for, but still, I didn't know the history. So I drained that oil (also allowed detailed inspection), and manually cleaned out the head stock. I saw nothing that concerned me as wear related, including lying on the bottom of the head stock. What I did find was a fair bit of black sooty like stuff, the same thing I've found in most such boxes. I cleaned all that up and refilled with (IIRC?) 3 gallons of appropriate oil. That was several years ago, and it still looks fresh.

[RSG]

You don't say what type of lathe (and I don't recall), though it clearly has an oil bath head stock.

It's a King Lathe - KC-1236 and it's about 5 years old now, I bought it new.

I asked my friend today what oil he gave me and when I showed him the container he said it looks like 10w oil. My lathe is spec'd to run EP68 so I think this is the problem. Am I correct in the notion that 10W oil is far lighter than EP68? Regardless I better do an oil change right away.

Edit- Come to think of it I have noticed lately that the headstock is awful warm once running for an hour or so. I can't recall it ever being so hot in the past. Could it be a result of wrong oil?

[SteveHGraham]

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

[spro]

I would attach a stiff wire to a strong small magnet and wick it around in there. If you tie a small baggie around the magnet first, the magnetic slurry will be apparent.

[John Hasler]

If it's straight SAE 10W engine oil the viscosity is low. 20W would be closer. What with the headstock heating up and silvery stuff in the oil I guess I'd seriously consider tearing it down for an inspection.

[GlennW]

My lathe is spec'd to run EP68 so I think this is the problem.

68 is usually 20 wt oil.