Oil Change - Jet geared head lathe

[DATo]

I need to change the oil in a Jet 13 X 40 GHE lathe which has sat idle for many years. The manual calls for Mobile "Heavy Medium" oil and doesn't say how much other than "fill to line on sight glass". I don't think I will need more than a couple of gallons but the only way I can buy it here is in a five gallon can for $167.

Does anyone know of an alternative oil I can use? On You Tube there is some guy replacing his oil in a somewhat similar lathe with straight 30 weight but I have no idea if he knows what the hell he's doing. I emailed Jet and a rep replied "ISO-68" as an alternative to "Heavy Medium" but, though I asked, failed to say how much I would need.

So in simple terms like "Straight 20 weight" or "Straight 30 weight" or "Hydraulic" (language a mere mortal can understand) can anyone tell me what oil would work and/or how much would be required on this specific lathe? I'll settle for any advice I can get at this stage.

[Glug]

DTE Heavy Medium circulating oil. I would not use hydraulic oil, because it is not the same.

I recently tried Zoro and have been thrilled with their service (especially after I ordered the wrong part), and prices. They have it in gallons. Free shipping on orders above $50. Nice surprise bonus for me - next day delivery due to proximity. This might be a good time to get a gallon of CRC-3-36 or LPS 2, etc. There is a 15% off promo when you sign up for their email coupons (zmail).

https://www.zoro.com/mobil-mobil-dte-heavy-medium-iso-68-1-gal-100959/i/G1618364/

The old oil in there is probably horrible. Could even be original mystery oil. You might want to do some flushing, maybe with clean kerosine (one pass only and of course don't turn it on), and then flush that with some oil. We don't know your Location (hint hint) but I would want the headstock warm before draining, to encourage a flush of debris, etc. A space heater and a tarp tent could help with that. Running would also warm the oil but that doesn't seem like a good idea.

No idea on the quantity you will need.

[Sparky_NY]

Might want to look at "Universal tractor lubricant" at tractor supply/ napa and other places. Its a general purpose lube that actually meets the requirements for those lathe heads quite well. Its cheap too ! (roughly $35 for a 5 gal pail) Its even specified by many farm equip manufacturers for use in their hydraulic systems as well as gear boxes, transmissions and more. I believe it is ISO 68 weight but not positive.

(this is what I used to replace the spindle oil in my cnc lathe which spec'd oil the same way as your Jet) Google search "Universal Tractor Fluid Lathe" and you well see its pretty common.

[reggie_obe]

Might want to look at "Universal tractor lubricant" at tractor supply/ napa and other places. Its a general purpose lube that actually meets the requirements for those lathe heads quite well. Its cheap too !

Sam's Club used to carry it in 5gal. pails as well.

[Sparky_NY]

Also,

Don't know if you have seen those Lucas oil stabilizer displays on auto parts store counters but its quite amazing what it difference it makes it oil clinging to gears and preventing dry starts. I put it in my Jet lathe when I changed the oil and it does make it quieter and keeps oil clinging on the gears when the lathe is sitting so it has lube on startup.

Some of course swear against using any additives, so its up to the individual. (note: athough its called engine oil additive, read the description, it talks about gear trains)

https://lucasoil.com/products/engine-oil-additives/heavy-duty-oil-stabilizer

[Sparky_NY]

Sam's Club used to carry it in 5gal. pails as well.

As well as O'Reillys, autozone, advance, napa and many other auto parts stores. Tractor supply often runs it on sale, $20 when on sale.

[DATo]

Many thanks for all your responses. I've read them all. In the meantime I've located an iso-VG-68 at Wal-Mart of all places which has a 5 star approval rating by customers. Don't know what the "VG" means ... hopefully "Very Good". Delivery time 3 days.

Any thoughts on this stuff?

[Glug]

Hydraulic systems, and fluid, are different. They have filters to collect suspended debris. Your lathe does not. This is also the oil that lubes the spindle bearings, which are presumed to be some variety of high precision.

Does it matter in a Jet lathe, especially one that does not have a clutch? Perhaps not. For some machines it certainly does.

Also, any dirt, dust or debris that get in that headstock while open will go through your bearings. That is a big deal, literally. Especially since you have no filtration. But, as the stories go, it may have casting sand and what not in there.

[Sparky_NY]

Many thanks for all your responses. I've read them all. In the meantime I've located an iso-VG-68 at Wal-Mart of all places which has a 5 star approval rating by customers. Don't know what the "VG" means ... hopefully "Very Good". Delivery time 3 days.

Any thoughts on this stuff?

Walmart has a few VG-68 oils I found but they all seem to refer to use in hydraulic applications only, no mention of gears or transmissions. Often its a matter of different/more additives. ISO 68 is merely the weight of the oil, doesn't tell you much else. I see the VG designation used in conjunction with ISO, ie ISO VG-68. I found hints that the VG nomenclature is possibly used overseas. It isn't that critical but personally I would like a ISO 68 weight oil that at least mentions usage in gear applications.

[Sparky_NY]

Hydraulic systems, and fluid, are different. They have filters to collect suspended debris. Your lathe does not. This is also the oil that lubes the spindle bearings, which are presumed to be some variety of high precision.

Does it matter in a Jet lathe, especially one that does not have a clutch? Perhaps not. For some machines it certainly does.

Also, any dirt, dust or debris that get in that headstock while open will go through your bearings. That is a big deal, literally. Especially since you have no filtration. But, as the stories go, it may have casting sand and what not in there.

+1 many put a magnet in the bottom of the head which isn't a bad idea.

[old mart]

Why not a good synthetic motor oil, say 5W40, it works with gears pretty well, just ask any owner of a Japanese motorcycle. This type of oil is superior for preventing "dry starts" as it clings to all the surfaces better than mineral oil. Also, a magnet secured within the sump will catch most of the ferrous particals in the oil.

[reggie_obe]

As well as O'Reillys, autozone, advance, napa and many other auto parts stores. Tractor supply often runs it on sale, $20 when on sale.

Just mentioned Sam's because they had 5 gal cheap hyd. oil at $13+ at one time and $16+ for the premium stuff.

[Willy]

I've always used an ISO 68 straight hydraulic oil in lathe headstocks and gearboxes without issue as these make excellent spindle oils and are heavily fortified with rust, oxidation, and robust anti-wear additives and are recommended for this type of service by the various refinerys that produce them.
This is not to be confused with TDH fluids (transmission-differential-hydraulic) that are also commonly used in some tractors, this is a totally different oil.

However if you want the Mobile DTE Medium Heavy ISO 68 I see it is available at Walmart at a reasonable price. I doubt you'll need more that the one gallon jug unless you are prone to spilling a lot.
And yes, install a magnetic drain plug while you are in there, cheap insurance.

[Willy]

Many thanks for all your responses. I've read them all. In the meantime I've located an iso-VG-68 at Wal-Mart of all places which has a 5 star approval rating by customers. Don't know what the "VG" means ... hopefully "Very Good". Delivery time 3 days.

Any thoughts on this stuff?

Sorry but I missed this post earlier.

ISO 68 simply refers to the viscosity of the oil per International Standardization Organization testing methods. We are much more familiar with SAE motor oil viscosity numbers like 10,20,30 etc. An ISO 68 viscosity oil is roughly equivalent to a high 20, low 30 SAE engine oil viscosity if you want to draw a comparison that means more to you, as it relates to something you may be more familiar with.
The "VG" only means viscosity grade and does not describe the type of oil. I'll assume for now that it is a straight hydraulic oil, which is perfectly fine for your intended use. If that is what it actually is.

[sch]

This is interesting. About 2006, when barrel of oil ranged from $50-70 I bought a 5 gal bucket of the Mobil DTE68 from a local distributor for ~$40-45. Now when
oil is running in the same price range at the well head, same bucket is 2x-3x the price, where gasoline in my area is $1.92-2.10/gal and the price fluctuates weekly.
Over the years other threads have endorsed the use of the relatively inexpensive hydraulic fluid mentioned at Tractor Supply or Sams in headstocks.
Fancy motor oils (multigrade) have been panned because of the suspension agents in them to keep debris suspended til filtered out by the oil filter,where in a lathe
you want that stuff to settle out or stick to a magnet. FWIW the Sams hydraulic bucket is ISO68.