Lathe headstock oil

[JackOfDiamonds]

My lathe manual says to change the headstock oil every 6 months.

It's a grizzly 4003 and uses iso 32 hydraulic oil.

Given there is no combustion byproducts to neutralize, which would deplete additives, and no viscosity modifiers that could break down, and no detergents that could become depleted, I don't know how the oil could ever wear out. So I'm thinking about extending the oil change interval, but I don't know why I shouldn't just extend it to "forever". There is a sight glass. What is the point of changing it?

 

[bcschief]

Moisture is a good reason. ISO 32 is very common hydraulic oil most auto parts stores should have it in a 5-gallon pail.

 

[Jswain]

How much money would you save if you didn't change it for 10 years vs if you changed it once a year?

How much money would it cost if you seized up your lathe in 6 years because you skipped those oil changes?

If the money it would cost you far exceeds the money you would save, that's why you change the oil. And the first oil change is likely the most important.

 

[rockettauto]

Gear to gear pressure alone can break down the oil itself. Oxidation makes it slightly acidic...wear products will contaminate it, moisture too, and nothing is totally sealed....hell I think there's a vent on that which means it's breathing in dust every time it cools down.

 

[Firebrick43]

Both BCScheif and rocketauto cover the basis of why you change any oil even if it doesn't have combustion by products. Lightly used machinery in unheated/conditioned shop spaces can have a lot of moisture in the oil. While most hydraulic oils can emulsify they can only hold about .5 percent water before phase separation causes issues. That water layer can even harbor oil eating algae that can plug passages up and filters or screens in little used systems.

And gear pressure absolutely can cause oil shear and therefore a decrease in viscosity.

 

[cannuck]

And gear pressure absolutely can cause oil shear and therefore a decrease in viscosity.

You can shear down additives, particularly VII (Viscosity Index Improvers) but the base stock generally holds up pretty well. By far THE highest shear application is going through a barely open hydraulic valve. The loads in a lathe headstock are extremely light - even in the gearing. Wouldn't get into any big hurry to change that oil as all you are doing is taking out the contaminants.

 

[rockettauto]

You can shear down additives, particularly VII (Viscosity Index Improvers) but the base stock generally holds up pretty well. By far THE highest shear application is going through a barely open hydraulic valve. The loads in a lathe headstock are extremely light - even in the gearing. Wouldn't get into any big hurry to change that oil as all you are doing is taking out the contaminants.

The shear stability test considered the most severe is running it in a tapered roller bearing for 20 hours as compared to the other tests that are considered less severe that involve passing it through an orifice at high pressure.

 

[Firebrick43]

You can shear down additives, particularly VII (Viscosity Index Improvers) but the base stock generally holds up pretty well. By far THE highest shear application is going through a barely open hydraulic valve. The loads in a lathe headstock are extremely light - even in the gearing. Wouldn't get into any big hurry to change that oil as all you are doing is taking out the contaminants.

We changed them every two years in an engine lathe. I wouldn't extend that to forever. We had a guy that was pencil whipping his PM's for some time. I had to do them after he had not done them in at least 4 years if not 6. The poor 16x30 monarch lathe smelled something terrible and the plastic nylon Geneva escapement wheel for the single dial shifter was so swollen it took both hands and a hard turn to shift gears due to the moisture in her. That escapement wheel was 927 dollars.

Its amazing what the tool makers will do for you if you baby their machines!

 

[dutchgray]

The interval is usually based around the machine being in use all day every day, for a hobby or intermittent use you can extend the interval quite a bit, but as others have said the oil does break down, gets dirty and gets moisture in it.

I would change it every two or three years.

I need to do my own lathe soon, need three gallons for the headstock in that.

 

[cannuck]

The shear stability test considered the most severe is running it in a tapered roller bearing for 20 hours as compared to the other tests that are considered less severe that involve passing it through an orifice at high pressure.

I assume you mean the Timken OK test - that I must point out is for testing EP ADDITIVEs, not shear of base stocks. I have used 4 ball, but not 2782. Will ask my daughter about long chain base stock shear down (within her grad school thesis) later today. Not saying it is not possible, but I have never observed it.

 

[cannuck]

The poor 16x30 monarch lathe smelled something terrible and the plastic nylon Geneva escapement wheel for the single dial shifter was so swollen it took both hands and a hard turn to shift gears due to the moisture in her. That escapement wheel was 927 dollars.

Most plastics will absorb SOME water, but I would doubt seriously headstock oil could transfer enough to swell an appropriately spec'd material. One of 2 problems seems more likely: screwup in material spec of the Geneva wheel, or wrong oil spec or off spec with additive or base stock not compatible with that plastic. I encounter similar problems with gaskets/orings/seals used with napthenic oils (HIGH solvency) where the polymer guys don't seem to know much about cyclic or aeromatic hydrocarbons.

 

[rockettauto]

I assume you mean the Timken OK test - that I must point out is for testing EP ADDITIVEs, not shear of base stocks. I have used 4 ball, but not 2782. Will ask my daughter about long chain base stock shear down (within her grad school thesis) later today. Not saying it is not possible, but I have never observed it.

CEC-L45-A-99....yes.. and it tests how much improvement the AW additives make in shear stability as compared to the base oil alone. It almost always does improve it's shear stability index.

I any case I've yet to see an available iso 32 on the shelf without an additive package.

 

[cannuck]

CEC-L45-A-99....yes.. and it tests how much improvement the AW additives make in shear stability as compared to the base oil alone. It almost always does improve it's shear stability index.

I any case I've yet to see an available iso 32 on the shelf without an additive package.

Yes, that is what the "AW" in AW32 means - anti-wear. There is indeed an EP component but most of the rest is anti corrosion, anti foaming and some other stuff that won't be affected. AW oils are about the "least formulated" with simplest, lowest cost additive package. What I have most experience with is VII additives that have very poor shear stability. Not having the apparatus have never looked at base stock shear - but that will be the topic at dinner tonight with the girl who did nothing but for a couple years. As I think back: her study was to first figure out how ZDDP actually worked (nobody previously actually knew the mechanism) and find a biologically produced molecule that would behave in same way. From what I remember, the magic was in the polarity imparted by chlorine that oriented molecules to have the end of long molecule sheared by large load and that was what made the EP additive work as opposed to fail.

 

[Firebrick43]

Most plastics will absorb SOME water, but I would doubt seriously headstock oil could transfer enough to swell an appropriately spec'd material. One of 2 problems seems more likely: screwup in material spec of the Geneva wheel, or wrong oil spec or off spec with additive or base stock not compatible with that plastic. I encounter similar problems with gaskets/orings/seals used with napthenic oils (HIGH solvency) where the polymer guys don't seem to know much about cyclic or aeromatic hydrocarbons.

Its assumed that the oil was DTE24. And that is backed up as mobile oils were the only one in the plant and had been for the 16 years I had been there. The tank was well marked. Of course someone could of put in DTE25. I doubt that they put in spindle oil like DTE06 or DTE10 as it didnt smell kerosene like or was real thin. The hydraulic functions were working correctly?

Who knows about the plastic used, and it was a 610 so that would put in in the 60's or early 70's if I remember correctly. It was a really nice lathe and everyone loved it except wished it was 36" long instead of 30"

I always used it if the part wouldn't fit on the hardinge super precisions.

 

[rockettauto]

Yes, that is what the "AW" in AW32 means - anti-wear. There is indeed an EP component but most of the rest is anti corrosion, anti foaming and some other stuff that won't be affected. AW oils are about the "least formulated" with simplest, lowest cost additive package. What I have most experience with is VII additives that have very poor shear stability. Not having the apparatus have never looked at base stock shear - but that will be the topic at dinner tonight with the girl who did nothing but for a couple years. As I think back: her study was to first figure out how ZDDP actually worked (nobody previously actually knew the mechanism) and find a biologically produced molecule that would behave in same way. From what I remember, the magic was in the polarity imparted by chlorine that oriented molecules to have the end of long molecule sheared by large load and that was what made the EP additive work as opposed to fail.

You're over my head there ..... As I understand it the AW additives improve shear stability so I'm guessing by default the base oils are even more limited without it.

I'm assuming if they can break down oil in a roller bearing in 20 hours far enough to make a measurable difference in viscosity it will break down over months of use in this gearbox, which I think actually uses a tapered roller for the headstock.

I'd make wild guess that the recommended change intervals though are at a 2x factor at least In the actual " necessary" frequency.

 

[cannuck]

You're over my head there ..... As I understand it the AW additives improve shear stability so I'm guessing by default the base oils are even more limited without it.

I'm assuming if they can break down oil in a roller bearing in 20 hours far enough to make a measurable difference in viscosity it will break down over months of use in this gearbox, which I think actually uses a tapered roller for the headstock.

I'd make wild guess that the recommended change intervals though are at a 2x factor at least In the actual " necessary" frequency.

As I mentioned, NO experience myself with OK test, but I think it ran by increasing pressure until there was failure or was it just fixed load and measure something in the oil after 20 hours? The loading on taper roller in headstock would be miniscule compared with what load I assume the Timken test rig applies. Think about the oil change interval of taper rollers in HD trailer applications - often hundreds of thousands of miles - only changed when there is a seal failure or bearing suspected. They do just fine for YEARS of service. Not thinking the issue is shear stability but breakdown of EP properties that this test is looking for. Will consult with the expert later and report what she has to say.

For rollers, I usually shoot for 32 CS @ operating temp - and don't normally worry to exceed R&O formulations in light duty. For critical stuff I go Group IV/V blend synth with EP additives, but what has always stumped me is if you go to ultra-precision bearings, SKF requires NO EP additives! Clearly I am still missing an important part of this puzzle.

 

[Sumboodie]

Its assumed that the oil was DTE24. And that is backed up as mobile oils were the only one in the plant and had been for the 16 years I had been there. The tank was well marked. Of course someone could of put in DTE25. I doubt that they put in spindle oil like DTE06 or DTE10 as it didnt smell kerosene like or was real thin. The hydraulic functions were working correctly?

Who knows about the plastic used, and it was a 610 so that would put in in the 60's or early 70's if I remember correctly. It was a really nice lathe and everyone loved it except wished it was 36" long instead of 30"

I always used it if the part wouldn't fit on the hardinge super precisions.

Assuming you mean Mobil DTE 24 and not "mobile".

It's a 32 weight hydraulic oil. DTE 25 is 46 weight.

Not familiar with a spindle oil DTE 10.... it's just hydraulic oil available from iso 15 to 150.

I usually spec Chevron Rando HDZ instead, since we are a Chevron distributor.

 

[Firebrick43]

Assuming you mean Mobil DTE 24 and not "mobile".

It's a 32 weight hydraulic oil. DTE 25 is 46 weight.

Not familiar with a spindle oil DTE 10.... it's just hydraulic oil available from iso 15 to 150.

I usually spec Chevron Rando HDZ instead, since we are a Chevron distributor.

It was the ISO 15. They just used it to lube and cool the bearings in medium speed spindles german spindles with 3 speed gear boxes. We didn't use oils that light for any hydraulic application. That was the mobil oil suggested by waldrich colburg.

I don't know why I said DTE 6, It should have been Velocite 6 and there is a 10 as well, that is high speed bearings that are not total loss lubed

 

[JackOfDiamonds]

Well I changed it after 4 years or so, but I feel like an enviro criminal because what came out looked clean enough to drink. I think that will be the last change for a long while.

 

[alfadan]

Hmm. It's like a 2hp lathe with straight cut gears run for an hour a week is easy on the oil...

Good peace of mind anyhow

 

[Steve_P]

I'm sure I've had the same oil in my air compressor for 10 years. Last time I changed it was at a similar interval and it came out looking like new. 50 years ago, there was no change interval on rear differential oil in most automobiles. I worked at a very high-volume small engine shop, with 6 full time mechanics in the summer, and we never changed the oil in the air compressor in the 5 years I worked there.

I'm not saying to never change oil, but unless it's a new gearset, or contaminated by combustion products....

 

[cannuck]

You're over my head there .....

Only got to speak with Big Kid for a few minutes - kids went bezerk so had to wrap things up. What I got was a sharp lesson in how academia works. She used a different test to measure tribological results from wear scar and was restricted in researching the material IN the wear scar with synchrotron. I forgot why she left academia until this sharp reminder: her thesis and related research were kept limited to an extremely small range as each thing she wanted to open up could have been a thesis topic for someone else. She wanted to do bearing and engine testing, but was stuck with wear scars. What she did have to say that was something I had never considered in lubricants: crude oil is LOADED with metals - even though we normally only report Nickel and Vanadium levels (as they foul hyro-treating catalysts). She presumes (with a fair bit of reason and credibility) that these related metal may impart many of the tribologically pertinent characteristics to the base oil and the related compounds within may well shear down and change viscosity and lubricity.

 

[dutchgray]

Well I changed it after 4 years or so, but I feel like an enviro criminal because what came out looked clean enough to drink. I think that will be the last change for a long while.

Keep some for general use in an oil can.