I've been running around in circles on this and I want to put it to bed so I can get to using my new lathe! I bought a CX706 from Busy Bee and the manual states to use a 20W machine oil for everything except the gearbox, and Mobilgear 627 in the gearboxes (apparently this is now called Mobilgear 600XP 100). Weird that they don't sell the oils considering how much of it they would probably sell.
So from everything I've learned about oils what I understand is that I shouldn't use motor oils in the gearbox, even if they're non-detergent... i've also learned that way oil is designed to be a bit sticky so that it doesn't drip off the surfaces it's supposed to be on. I also learned that 20W is equal to SAE20 or ISO68, and the Mobilgear is SAE30/ISO100, in terms of viscosities. McMaster Carr only has 6-packs of the jugs of equivalent/ideal products. I've read from some people that Anti-Wear Hydraulic Oil (
like this one) should be good in the gearbox, but I also don't want to void my warranty. I certainly prefer to get a product at a retail outlet if I can, so that I have a reliable way to get more when I need it. I checked the Precision Matthews (same machine) manual and it lists 75W-80 as a gearbox oil, and the Weiss manual (also same machine) lists Mobil DTE Heavy Medium (an ISO 68 hydraulic oil) for the gearboxes.
In case you can't tell I'm brand new to all of this stuff, so any insight would be appreciated!