# Sebastian gear box oil



## Shotgun (Jun 13, 2022)

I've had the lathe a couple weeks now, and now that I've got the chuck backplate off and 220V power ran out to it, I just had to pull the cover off the headstock gearbox.  What I found has me confused, though.

The soft, pliable permatex around the top tells me that someone has been in there recently.  The beautiful, factory new looking gears tells me that this thing was kept in some nice condition, or that the somebody who had it open recently did a LOT of restoration work to it.  I can't see even a hint of rust anywhere, or even wear on the teeth.  I did run a magnet through the bottom of it, and pulled up what might be described as black mud.

The thing that really surprised me, and I'm still at loss to explain, is the smell.  Took me a minute to come to "gas station bathroom" as the name for it.  One of those seedy ones on a rarely used highway exit.  I first thought some moisture had gotten in, but that doesn't comport with the shiney, rust free gears.  Is there a type of oil that maintains a musty smell?


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## benmychree (Jun 13, 2022)

Sounds like the Mobil Vactra series. if I am reading the smellovision correctly.


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## Martin W (Jun 14, 2022)

I wouldn't worry about someone else being in there before. Probably popped the cover off to have a look, just as you have. Maybe think about getting rid of the Permatex and make a paper gasket. You wouldn't want a chunck of that plugging up an oil hole
Cheers
Martin


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## Shotgun (Jun 14, 2022)

benmychree said:


> Sounds like the Mobil Vactra series. if I am reading the smellovision correctly.


Sort of a low level acrid, mildewed chlorine mixed with urine type smell?


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## FOMOGO (Jun 14, 2022)

Assuming it has a drain plug, just rinse it out with some diesel (may have to take out a small loan), and call it good, If all the bearings/bushings feel good. Mike


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## Shotgun (Jun 14, 2022)

FOMOGO said:


> Assuming it has a drain plug, just rinse it out with some diesel (may have to take out a small loan), and call it good, If all the bearings/bushings feel good. Mike


I may end up doing that.  But, what's there doesn't look very dirty, and if that is the way that oil smells, I'd prefer not to go through the effort, stench, mess, and expense to replace new oil.


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## Shotgun (Jun 14, 2022)

Shotgun said:


> I may end up doing that.  But, what's there doesn't look very dirty, and if that is the way that oil smells, I'd prefer not to go through the effort, stench, mess, and expense to replace new oil.



I'd like to correct myself:  The smell is more like the mildew/chemical smell of a public sauna.

Man, I think I'm thinking about this way too much.  It's weird, because it just is not a normal "oil" smell.


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## matthewsx (Jun 14, 2022)

Yes, change the oil. If for no other reason than you don’t know when it was changed last. 

I use hydraulic “tractor oil” in the right grade and buy it by the 5 gallon bucket. Most important thing is to make sure it’s the stuff that doesn’t attack brass/bronze. 

John


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## projectnut (Jun 14, 2022)

If the previous owner was a member of the Sheldon Lathe board, I would bet it had 10W-30 motor oil in it.  John Knox former Sheldon Design Engineer was recommending 10W-30 to replace the oil in all the Sheldon and Sebastian products.  He felt it was magnitudes better than anything available when the machines were built.

I've been using 10W-30 in my Sheldon MW 56P for 7 years with no ill effects.   In fact, I ran the proposal by the lubrication Engineer on our company staff before doing so.   He agreed with john Knox assessment.  In my case the machine usually is run 20 to 30 hours a month.  There have been weeks where I've run it for over 40 hours, and others where it's set idle.


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## woodchucker (Jun 14, 2022)

Shotgun said:


> I've had the lathe a couple weeks now, and now that I've got the chuck backplate off and 220V power ran out to it, I just had to pull the cover off the headstock gearbox.  What I found has me confused, though.
> 
> The soft, pliable permatex around the top tells me that someone has been in there recently.  The beautiful, factory new looking gears tells me that this thing was kept in some nice condition, or that the somebody who had it open recently did a LOT of restoration work to it.  I can't see even a hint of rust anywhere, or even wear on the teeth.  I did run a magnet through the bottom of it, and pulled up what might be described as black mud.
> 
> ...


gear oil always had that smell to me. the type you put in a manual tranny or rear.


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## mksj (Jun 14, 2022)

FYI, the use of detergent oil appears to have been suggested for total loss oiling systems where it is felt that the detergent oil might be more effective in flushing out impurities and varnishes, but I did not see any recommendations for use in recirculating oil systems (that do not use filters). The oils these days are much better than what was available in years past, and for a low speed lathe I think having the proper viscosity for the operating temperature is the most important factor. Often with a 30W engine oil when used in a lathe, it proves too viscous and the bearing will heat up. Engine oils are designed for much higher operating temperatures for their rated viscosity, vs. gearbox circulating oils and hydraulic oils. Synthetic oils can be a problem with older seals and will often leak more, I have used synthetic oils in a high speed mill head and did increase the top RPM and the bearing ran significantly cooler, but in my gear head lathe I use ISO68 circulating oil rated for both gears and hydraulic systems. Wearing out the oil/failure is not an issue as opposed to moisture contamination over time, thus changing the oil annually. I think this may be a contributing factor to the smell as well as the oil degrading with time gets that gym/bathroom smelly stench.



			Lubricants to use on the moving parts of a lathe???? - Page 3 - The Home Machinist!
		

Re: Lubricants to use on the moving parts of a lathe????​I don't dispute the information of this thread. Mr. Knox wouldn't be a guru if this wasn't taken out of context. We have learned here that it is a "total loss" type lubrication.  I would think this is but a step to flood out impurities and Then the proper non-detergent be used. Heck, folks would use a mix of kerosene in engines for a bit, just to get the gunk out.
There is no reason for this to be any argument..


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## benmychree (Jun 14, 2022)

I would never use an automotive gear oil in a machine tool; EP oils especially have ingredients in them that erode yellow metals, and there is no need or benefit to use extreme pressure lubricants with anything but but hypoid gearsets.  I once saw a worm gear set completely worn out on a bottling machine in less than a year because someone filled it with EP oil when the gear was replaced.


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## matthewsx (Jun 14, 2022)

Oil:

Make sure you have enough
Make sure it's the right kind
Change it on a regular basis

In that order IMHO.

John


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## Richard King 2 (Jun 16, 2022)

I have been putting Vactra 2 way oil in Headstocks for 50+ years and never had an issue.  Way oil is sticky and it does not run off the gears or run out of bearings.  When it starts up oil is lubricating right away.  If you had black mud in the bottom then use some kerosene or diesel fuel to rinse like was suggested.  I would not run it.  Just pour it in, let it set in there overnight, stir it up and drain it.  I also agree, make a gasket for the cover.  Use Permatex soft to attach the gasket to the underside of the cover and as the one guy said check for lubrication holes so you don't cover them.  I also would NEVER put motor oil in a lathe.


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## benmychree (Jun 16, 2022)

Richard King 2 said:


> I have been putting Vactra 2 way oil in Headstocks for 50+ years and never had an issue.  Way oil is sticky and it does not run off the gears or run out of bearings.  When it starts up oil is lubricating right away.  If you had black mud in the bottom then use some kerosene or diesel fuel to rinse like was suggested.  I would not run it.  Just pour it in, let it set in there overnight, stir it up and drain it.  I also agree, make a gasket for the cover.  Use Permatex soft to attach the gasket to the underside of the cover and as the one guy said check for lubrication holes so you don't cover them.  I also would NEVER put motor oil in a lathe.


I quite agree Rich, I have used in my Regal Leblond lathe's headstick and apron for likely nearly 40 years now, and in several other machines such as mills, grinders, my shaper, what have you ---- multigrade (detergent) will hold particles in suspension, and without filtering systems, all that stuff continues to circulate through the moving parts to their detriment.


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## Shotgun (Jun 16, 2022)

I was able to find SAE30, non-detergent comrpessor oil.  Sheldon's manual for their Sebastian (slightly younger than mine) called for 30wt, so I figure I'm good. 

When I drained what was in there, the initial part was watery, brown goo.  Oil, being lighter than water, floats to the top.  All the water was sealed air-tight in the bottom.  Not able to promote rust on anything since it is sealed off, but is able to rot the oil.  The top portion still looks clean and nice, because I hadn't run it enough to stir up the nasty stuff from the bottom.  Note to self:  When the oil is clean, you can see the bottom of the gearbox.

Didn't really know how much to fill it, but two gallons resulted in the bottom of the spindle bearings being covered.  Now, I find that the seal on the spindle nose is leaking.  Either I added two much, or the seal was just dry rotted.  My money is on the latter.


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## benmychree (Jun 16, 2022)

Shotgun said:


> I was able to find SAE30, non-detergent comrpessor oil.  Sheldon's manual for their Sebastian (slightly younger than mine) called for 30wt, so I figure I'm good.
> 
> When I drained what was in there, the initial part was watery, brown goo.  Oil, being lighter than water, floats to the top.  All the water was sealed air-tight in the bottom.  Not able to promote rust on anything since it is sealed off, but is able to rot the oil.  The top portion still looks clean and nice, because I hadn't run it enough to stir up the nasty stuff from the bottom.  Note to self:  When the oil is clean, you can see the bottom of the gearbox.
> 
> Didn't really know how much to fill it, but two gallons resulted in the bottom of the spindle bearings being covered.  Now, I find that the seal on the spindle nose is leaking.  Either I added two much, or the seal was just dry rotted.  My money is on the latter.


If my experience with the several gear head lathes can be relied on, having the oil level above the bottom of the bearings is way too much, the oil level should be just above the bottom of the larger gears, where it can be thrown around to lube all the other parts in the gearbox, too much oil can cause overheating and failure of antifriction bearings, which need only a small amount of oil  Many lathes have no real seals on the spindle, only laberinth arrangements to exclude chips from the bearings.  Chips and abrasive matter would quickly destroy shaft seals on machine tools.


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