# Looking for a suggestion for gear oil for the headstock of a lathe...



## Dabbler (Nov 26, 2018)

I just acquired a 1440 gear head lathe, and I want to replace the oil in the headstock.  What do you use and why?


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## Ulma Doctor (Nov 26, 2018)

ISO32 Mobil DTE light
it's the OEM equivalent fluid


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## Downwindtracker2 (Nov 26, 2018)

Lucky you , may I say I'm a little green, chuckle .  There are all sort of special recommendations . I looked up the crisscross for oil wt and I found diff oil matches, get some 80-140 syn. You can't get better oil. I use Lucas. It easy to find as well. It doesn't eat brass.  Well, you can buy better, but you have to buy a drum and it would cost as much as your lathe.


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## petertha (Nov 26, 2018)

Here is what my manual says ('97 vintage 14x40). I would have to check but I believe this oil is similar to what I got at the time for the headstock gearbox from CDN Tire. The sight glass looks very clean but probably time for a flush for me too. 

I also use the same oil that goes in from the side .......riiiight by that bank of electrical switches & buttons...... & flows into a felt padded tray right about where the #14 points to.  That then somewhat distributes over the change gears below. Much thinner & it drips through too fast. Much thicker & it kind of hangs up in the felt.Your lathe might be newer gen, but anyway maybe helps.


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## mksj (Nov 26, 2018)

Agree with Ulma Doctor, ISO32 gear head oil is what is most commonly used and reasonably priced. Multi-viscosity oils used in cars and differentials are not recommended, and based on different operating temperatures ranges. The 80-140 (ISO  100-460) syn is way more expensive  and significantly more viscous then ISO32, this will lead to increased friction and possible bearing failure due to lack of splash lubrication getting to the top of the head and into the lubrication channels to the bearings. Just about every gear head lathe specifies ISO32 in the headstock and ISO68 in the gearbox, I do not see any reason to deviate from this unless you live in the Arctic Circle or the tropics. No need for anything fancy for this application. Oils for differentials like the Amsoil have friction modifiers along with other agents specific to limited slip differentials that increase the friction. They have no place in gearhead lathes. Synthetic oils should not be used on new machinery until they are broken in, after that point they may have some application if you want to have extended oil intervals. You still should use a straight weight per the manufactures recommendation.

I have used Amsoil Hypoid Marine (SAE 75W/90, SAE 30 or ISO 100) synthetic oil in gear head mills that specify ISO100 oil with good results, also synthetic oils are used in other machinery like compressors that give much longer oil change intervals. You still have issues of condensation and contamination which may limit the length of the oil change intervals.

https://www.engineeringtoolbox.com/iso-vg-grade-d_1206.html

Added info: Most oils will indicate if they can be used with yellow metals (Copper strip corrosion test), not all EP additives attack yellow metals, and the newer sulfur based versions are inert (inactive) at room temperature and are activated with heat. So although the Amsoil Hypoid Marine oil mentioned above has EP additives it is safe to use with yellow metals, this was also confirmed with Amsoil's technical department. You should not need EP additives with standard straight cut gears, but almost all gear oils have some form of anti-wear additives. 
https://www.machinerylubrication.com/Read/28958/ep-additives-effects


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## Bob Korves (Nov 26, 2018)

petertha said:


> Here is what my manual says ('97 vintage 14x40). I would have to check but I believe this oil is similar to what I got at the time for the headstock gearbox from CDN Tire. The sight glass looks very clean but probably time for a flush for me too.
> 
> I also use the same oil that goes in from the side .......riiiight by that bank of electrical switches & buttons...... & flows into a felt padded tray right about where the #14 points to.  That then somewhat distributes over the change gears below. Much thinner & it drips through too fast. Much thicker & it kind of hangs up in the felt.Your lathe might be newer gen, but anyway maybe helps.


Extreme pressure (EP) gear oils will eat yellow metals (brass, copper, etc.)  Lathe gearboxes often have brass or bronze bushings, clutches, and washers.  Do not use EP oils with yellow metals!


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## Bob Korves (Nov 26, 2018)

Dabbler said:


> I just acquired a 1440 gear head lathe, and I want to replace the oil in the headstock.  What do you use and why?


If it is an Asian lathe use AW32 hydraulic oil.  It is the correct viscosity, and AW32 meets the specs easily and costs much less than specialty oils.  AW stands for "anti wear', it contains anti wear additives.


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## middle.road (Nov 26, 2018)

Mine matches what Peter already posted.
Here's one from the Grizzly manual for a G0709:


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## middle.road (Nov 26, 2018)

Bob Korves said:


> Extreme pressure (EP) gear oils will eat yellow metals (brass, copper, etc.)  Lathe gearboxes often have brass or bronze bushings, clutches, and washers.  Do not use EP oils with yellow metals!


As the saying goes, "Learn something new each and every day." This one is very pertinent.


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## petertha (Nov 26, 2018)

Bob Korves said:


> Extreme pressure (EP) gear oils will eat yellow metals (brass, copper, etc.)  Lathe gearboxes often have brass or bronze bushings, clutches, and washers.  Do not use EP oils with yellow metals!



OK, that's real good to know. I'll confirm what I have, maybe its just the weight I remember. I feel like I've heard this 'eats brass' before & someone else said - yes, but are likely found within many kinds of gearboxes or no - only if it contains sulfur...

What would be a typical applications of an EP oil? My first random Google pick. Fancy that, I swear I didn't weight the dice. It says_ EP Gear Oil is non-corrosive to brass, bronze, steel or other alloys_. https://www.lsc-online.com/industrial-ep-gear-oil/


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## Downwindtracker2 (Nov 27, 2018)

It's the extreme pressure additives . Don't use it in Radicons , a brand name of right angle worm drive reducers much like using Kleenex  for facial tissue . I don't know how many times I've had to tell guys that. The science of lubrication is long and complicated , it was pain to study .  Every oil company seems to have their own names for various oils to add to the confusion. That's why using 80-140 synthetic differential makes life simple. In spite of the higher numbers , it's right weight. You want the good stuff, the cheap  stuff may have EP additives.


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## petertha (Nov 27, 2018)

Information overload. Certainly seems like a thing to watch out for
https://www.machinerylubrication.com/Read/28958/ep-additives-effects

And topic even comes up under hydraulic oils
https://forums.noria.com/topic/hydralic-oil-additives-that-deplete-brass-and-copper


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## Bob Korves (Nov 27, 2018)

Lathe gear heads do not have high pressure gearing.  The most common high pressure gearing is hypoid automotive differential gears.  Lathe gearboxes have no hypoid gearing, they just need to be lubricated, and the oil changed at intervals to get the crud out.  "Getting fancy" is often getting stupid with lubricants.


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## Dabbler (Nov 27, 2018)

WOW.  Lots of info.  The oil in the new machine is very good looking, for a 13 year old lathe.  It looks like it has never been used, much.  My owners manual doesn't specify any oil weights, just intervals for changing it!

BTW in the winter I run my machines at about 7C (45 degrees F), so I really think ISO 32 is the max I can get away with... 

I agree with the above, that simpler is better.  I will be careful to check about the yellow metals problem.   

Petertha , I should have a look at your user's manual some time...  Perhaps when we get together next!

Thanks for all your help and support!


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## ddickey (Nov 27, 2018)

I had the same questions.
https://www.hobby-machinist.com/threads/changing-headstock-oil.63546/


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## Dabbler (Nov 27, 2018)

Thanks, ddickey - I should have done a search before posting, but it is nice to have some of the new links on HP additives, etc!


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## Dabbler (Nov 29, 2018)

Downwind, I've been talking with technical staff for lubricants for two days now.  Some of the above comments are reflected in the warnings from professionals in the lube field. I'd need to know the exact product you found that doesn't eat brass.

-It seems that diff oil has two problems in the headstock of a lathe.  One is that they contain additives that increase the friction on the gear, while reducing the wear on the gear. This is because the relative speed of the gears is very low, and there is sliding friction on the hypoid gears,  Since our headstocks are spur gears, it is a different speed/friction profile.

Second. a lot of them, but but not all of them,  have 'free sulfer' EP additives, which can deteriorate the bronze bushings in the heastock. The additives make a 'soap' under pressure that protects the gears and reduces friction. (yes and they add stuff to restore that friction - I don't know why)


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## Downwindtracker2 (Nov 29, 2018)

We used SWEPCO brand  on our big wire drawing machine. It was a moly added oil. The company got the change over paid with a Power Smart program. That much of a power saving. This machine had worm and wheel (brass)reduction. Someone in eastern US got a great machine. Surprisingly the  oil had labeling as a differential oil. I use Lucas. Someone on the net recommended it as it didn't eat brass.( I know) I can get it locally in US quarts at the auto parts without going into Vancouver and buying a pail . Check out Lucas.


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## Dabbler (Nov 29, 2018)

Hmmm.  It would be useful to know the Lucas Product Code for a reference.  I found a Shell lubicant I can get locally, and I need 6 litres, so it is cheaper by the 5gal bucket. I can use it in my bandsaw that is due for a rebuild Very Soon Now.  I'll post the Shell number as soon as I'm sure it is the right one.


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## Dabbler (Dec 6, 2018)

I found out from the actual importer of my lathe top use AW 32 Hydraulic oil in both the headstock and the apron/crossslide.

Problem solved.  Thanks for all your help!  (and nice call for all those who had it right the first time!)


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## Bob Korves (Dec 6, 2018)

Dabbler said:


> Problem solved. Thanks for all your help! (and nice call for all those who had it right the first time!)


You did the correct thing by researching more deeply.  It is not a good idea to use something that will cause more harm than good, and well worth learning the differences.


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## matthewsx (Aug 10, 2020)

Dredging up an oldy....




$30 at Tractor Supply, any reason not to use it in my Bolton 13x40?

John


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## Dabbler (Aug 11, 2020)

@matthewsx  it looks quite good.  Might be even better for me, as my shop is *cold* in the winter.


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## NortonDommi (Aug 11, 2020)

Hydraulic oils designed for multipurpose use such as the tractor oil is perfect for the job. They are straight weight oils so pick according to temperature. I use Sino ISO 46. All manufactures have warnings if they shouldn't be used with certain materials.
Here's an example:


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