Milling machine transmission oil

[lrak]

So this mill was from the 1970's-80s and the manual calls for Shell X-100 S.A.E. 10 W which I don't think is made anymore. The other bit is I'm not sure the old oil was ever optimal for this transmission - it had 5 worn out brass forks (for changing gears) that came with it. Running at high speed the spindle runs at 4200 RPM - and the brass fork is holding a coupler running at spindle speed.

The other parts lubricated are large gears - roller bearings.

Any ideas of what modern oil to use in this machine?

 

[Job]

Maybe previous owners used the wrong oil. Mobil Velocite 6, 8, or 10 may be close, better even. I have a gallon of 6 and 10 for machines.

https://www.mobil.com/en-us/industrial/pds/gl-xx-mobil-velocite-oil-no-series

 

[lrak]

@Farnsworth

Velocite is a spindle oil - this is the transmission that drives the spindle.

SAE 10 is about a ISO 32 - I think velocite only goes up to ISO - 22

Besides the yoke there are large gears (largest is 6.5" diameter) - roller bearings on a 1.5" shaft - ball bearings as well.

Probably should be a detergent oil with about the same weight, but with modern anti-wear properties - and the steel/brass yoke contact may (or may not) mean something to oil engineers that know more than I do.

If I was a betting man - I bet they specified the same oil that they saw Bridgeport using back in the 1930's and no ever thought about modern oils. ( if the seals leak people use cheap oil in mill transmissions, but this has new seals).

Could be velocite 10 would work - about a SAE-5. Can't see anything that says if velocite is a detergent oil?

 

[zeng]

It requres a transmission oil .
SAE 10W typically has a KV@40*C of about 40 cSt.
Hence an industrial transmission gear oil of ISO 46 (or ISO 32) would be an appropriate replacement.

 

[Job]

From another thread Royal Purple for tractor. Scroll to page 42 it shows iso 22 would be SAE 10w engine oil. Velo 10 is iso 22. It just a suggestion. Shell x100 is motor oil. They spec 10w motor oil. I had a surface grinder and it spec'd 10w Texaco Ursa among others. Don't know who makes 10w now.
I think 10w-30 synthetic motor oil may be a good modern match because how hot does it get anyway and if it does get warm the oil just thickens a little.

http://www.royalpurplemena.com/product-categories/Royal Purple 2014 Industrial Catalog.pdf

 

[Curtis008]

"If it gets warm the oil thickens a little" I have never heard of any oil thickening as it gets warmer? But yes 10w-30 synthetic would be a good choice in my opinion.

 

[lrak]

I think Zeng has this right. There is no combustion chamber. Motor oils are a compromise to deal with combustion gasses and some extremes in temperatures.

First, synthetic is not one thing. It can mean modified oil, or PAO or PAG or a mix. I probably want synthetic (PAG) for the lower viscosity.. but it should be a gearbox oil WITHOUT the synchronizer additives.

I really think the motor-oil spec comes from what someone thought was readily available and good enough in the 1930's.

Sulfur additives are probably a bad idea due to the brass - my biggest problem is I need a couple of quarts ( could be what dictated the initial specification ) .. most of this stuff comes in barrels..

(OT a bit: I did find this https://recondoil.com/gear-oil-guide/ limited help but interesting. There is a clip from https://youtu.be/Z7NpsMZ9pBQ with interesting bits about the NEW GL-4 oils )

I think a thinner oil makes sense where a shaft can be spinning at 4,200 RPM for an hour at a time.. Thicker oil would just get hot.

So My biggest problem is who would have the right stuff and how to buy a small quantity?

 

[zeng]

Originally Posted by lrak
- my biggest problem is I need a couple of quarts ( could be what dictated the initial specification ) .. most of this stuff comes in barrels..

...............

So My biggest problem is who would have the right stuff and how to buy a small quantity?



You're right that the shear stable monograde industrial gear oils in ISO 32/46 comes in barrels .
However automotive transmission oils of KV@40*C of 32/46/68 cSt are available in quarts .
You may consider shear stable one in monograde MTF SAE 75W , or
Next one Chrysler ATF +4 is prefered to LV Dexron VI .
You have more choices of lesser shear stability in MTF 75W80 or general ATF's .

 

[lrak]

@zeng


I know manual transmission oil has additives so the syncronizers grab - perhaps the same is true for automatic clutch bands?


I think Mobil Delvac 1 Gear Oil 75W90 is a possible candidate - (what threw me was that gear oil and motor oil use different SAE grade numbers - SAE75-gear and SAE10-motor are both about ISO 32)..
But - the specs say it is cST/100 of 14 - more like ISO 100...

I don't seem to be able to find any API MT-1 that is ISO 32 - so back to other options.

 

[lrak]

@zeng

Looks like ATF+4 ought to work. I think it is a PAO with some special additives..
The only bit I know is they don't like oxygen - but this gear housing is sealed other than a sintered breather - which I could put a balloon on.

Thanks for your comments - never thought I would learn this much about oils. I once read a text-book on oil refining - electric separation of water and oil - bits about PAO, PAG, and esters - but never realized just how many details there are.

 

[lrak]

Ended up going with some SHC-624 - a bit of overkill, but hopefully the fork will wear longer.

 

[bruce381]

I always start at the manual lube tag as such it says
" the manual calls for Shell X-100 S.A.E. 10" thats a 32 or 46 ISO oil.
if you cannot find a straight wt 10wt motor SF or SL oil go with a 46 AW hydraulic oil.