Is cheaper hydraulic oil OK?

[Dabbler]

REGARDING HYDRAULIC OIL AND BRASS/BRONZE

I went deep down the rabbit hole last year on this issue. An argument broke out over this issue somewhere else, and I needed an answer...

Your provider will know if your oil has sulfur anti-wear additives. If it does, then it is not compatible with brass. The sulfur leaches the bronze, making it porous and brittle.

 

[mksj]

I am not aware of any hydraulic oils that have EP additives that typically contain sulfur, in addition the current generation of EP additives need to be activated with heat to be effective. The issue is often seen when individuals use gear oils such as those used in differentials were there are hypoid type or bevel gears. There are additional issues with the EP additives that they can attach to surfaces, and literally bond so tightly that they can tear the surface off of the substrate. This can be seen with transmission synchros , clutch packs, softer metals, etc. Brass is also much more susceptible to leaching vs. bronze. See below links and discussion of the copper corrosion strip test. Also note that the test is performed at 40 degrees C and again at 100 degrees C, the latter to activate the EP additives. Some additional links below on the subject. It is also important to take this into account when using gear oils in the mills/gearboxes which are subject to higher operating temperatures and often use yellow metals for bearings and rods. As noted above, you can contact the oil company to ask if it is safe to use with yellow metals, I have done this with both Mobil and Amsoil on some of their products.
https://www.machinerylubrication.com/Read/28958/ep-additives-effects

Limitations of Extreme Pressure Additives

Chlorine, potassium-borate and sulfur-phosphorus extreme pressure (EP) additives are primarily used for industrial gear lubricants. These additives are temperature-activated and react with metal...

www.machinerylubrication.com

Lubricant Additives - A Practical Guide

A practical overview of oil and lubricant additives without all the chemistry.

www.machinerylubrication.com

 

[bigwave]

I am brand new and starting to learn. I just bought a lathe from Precision Matthews (1440GT) and will be picking it up later this week. I notice they spec Mobil DTE heavy/medium iso 68 SAE 20 grade oil. I looked at MSC and they want $175 for 5 gallons. I read several other posts on this forum and wanted to know if I can buy other brands that are in the $40-50 dollar range. Are they basically the same thing or am I making a mistake. Rural King has harvest King AW6820W for $14 dollars for 2 gallon jug. Will this do? Or is it important to buy the stuff for $175 Thanks

You *can* order Mobil Hydraulic Oil in 1-gallon quantities from MSC, Zoro and others.

I have an Emco lathe which spec's DTE25 and VG68 for Guideway -- so that's what I ordered yesterday. I'm guessing it will be fine but I've not yet dumped it int the headstock. Also, Lithium high pressure grease is spec'd as "NLGI 2". I looked up Amsoil as well and you can get their Hydraulic Oil for VG46 in 1 quart quantities for similar spec ($15/Qt direct). See line items attached for Mobil product from MSC. About $100 for all three (ouch!) but I was in a jamb and MSC has a warehouse in Reno so I get it in a day over here in NorCal-- can't let my lathe run without oil, you know..

Good luck.

-Dave

 

[bigwave]

You *can* order Mobil Hydraulic Oil in 1-gallon quantities from MSC, Zoro and others.

I have an Emco lathe which spec's DTE25 and VG68 for Guideway -- so that's what I ordered yesterday. I'm guessing it will be fine but I've not yet dumped it int the headstock. Also, Lithium high pressure grease is spec'd as "NLGI 2". I looked up Amsoil as well and you can get their Hydraulic Oil for VG46 in 1 quart quantities for similar spec ($15/Qt direct). See line items attached for Mobil product from MSC. About $100 for all three (ouch!) but I was in a jamb and MSC has a warehouse in Reno so I get it in a day over here in NorCal-- can't let my lathe run without oil, you know..

Good luck.

-Dave

small update: the above referenced Way Oil is on a web special at MSC right now for $25.99/gal - I missed this when I ordered ..ugh..I guess you have to select the item from the specials page. -- i have no affiliation with MSC, BTW.

 

[7milesup]

Thanks for the heads up. Just ordered a gallon.