South Bend 9 Lathe Oil Recommendations

In this video I will be showing you what type of oils I’m using on my 1948 South Bend 9a lathe. I had some people request this in the past. The oils I am using are synthetic, I’ve been using this oil since I purchased the lathe in 2016. The reason for using this oil is that I always have it on hand as it’s used in my vehicles, unfortunately it is more expensive. It is a much better quality oil, it has a better surface bond, works better across a larger temperature range, less friction, and doesn’t gum up.
Mobile Vactra #2: amzn.to/3INgXrZ
Amsoil 75w-90: www.amsoil.ca/p/severe-gear-7...
Amsoil ATF: www.amsoil.ca/p/signature-ser...
First is way oil, the recommended oil for this is Mobile Vactra #2 which is a lubricant designed for machining equipment. It’s an ISO 68 grade, meaning it’s a mineral-based hydraulic fluid. I was originally using Amsoil’s synthetic gear oil 75W-90 which did seem to work well. It was almost impossible to find the Mobile Vactra #2. So the was ordered from the US Amazon. Lubrication wise the Amsoil does appear to be more slippery, but in the hot weather, the Vactra does have much better surface tension. I won’t get into the technical specs here as I’m using the recommended version.
Next is spindle oil, the recommended oil is Mobile Velocite #10 which is a hydraulic oil but also lists its use on spindle applications too. For this I am using Amsoil Signature Series synthetic ATF instead, it is used on power steering systems too, it is also a form of hydraulic oil. Comparing the kinematic viscosity, Velocite #10 is a thinner oil. I have been running the thicker ATF and have been closely monitoring the spindle, I do notice a little seepage around the spindle areas and it does require top ups in the oil caps. I have checked the heat when it’s running and there doesn’t seem to be any concern either. I am using the Amsoil ATF in the rear pulley bushings too.
Specifically looking up the Velocite specs, they don’t list all the same specs as Amsoil has published. I did look up other brands that supply ISO 22. The viscosity index is used to determine how an oil’s viscosity is affected by temperature changes. The higher the number, the more stable the oil is in different temperature changes. From what I’ve found, ISO 22 from another manufacturer was listed at 161, while the Amsoil product is listed at 165, meaning it’s slightly more stable.
Next was using the same source for the four-ball wear test, both using the same ASTM D4172 parameters, the other manufacturer was 0.42mm, while the Amsoil is 0.39mm, meaning that the Amsoil has a better load carrying properties.
Next is the gearbox oil. The recommendation is Mobile DTE24, this is a hydraulic oil but I’ve replaced this with is Amsoil’s synthetic gear oil, 75W-90. Both have a 1B Copper Corrosion rating, any areas where the Amsoil has been in contact with have zero signs of corrosion. There is a substantial difference between the kinematic viscosity at 40 degrees celsius or 104 degrees Fahrenheit, the Amsoil is at 102.4 cSt so it’s much thicker than compared to the DTE24 which is only 31.5 cSt. At 100 degrees celsius or 212 degrees Fahrenheit, it’s closer at 15.9 vs 5.3 cSt, however it’ll most likely ever see this temperature during operation. Viscosity index between the two, DTE24 is 98 and the 75W-90 is rated at 166, meaning it’s much more stable at a wider range of temperatures.
For all other areas requiring lubrication, Mobile DTE Heavy-Medium ISO 68 which is a circulating oil that is required and instead I’m using the same synthetic gear oil as previous, 75W-90. Again it has the same IB Copper Corrosion rating. Again the Amsoil version is thicker in both kinematic viscosity temperature ranges, the heavy medium is rated at 65.1 cSt at 40 degrees celsius or 104 degrees Fahrenheit and 8.7 cSt at 100 degrees celsius or 212 degrees Fahrenheit. Its viscosity index is only 95, so it’s certainly less stable than the 75W-90 from Amsoil.

[@JohnBobRoger]

Matt..great Vid..I'm new to SB9....can you please clarify the "Other Lub" category? Is it the Amsoil Synthetic " Severe" Gear Oil 75W90 Gear Oil that your using? Thanks kindly.