I think the only concern is that a detergent oil will hold water in
suspension. In an engine the water gets heated out, the lathe doesn't get
hot, so you have to run the lathe up to 10,000 RPM to get it hot enough to
keep the oil water-free or, change the oil out more frequently.

"stanley baer" wrote in message
...
I have a large Monarch lathe built in 1944. It has a geared head,a plain
bearing spindle and some sort of oiling pump to lubricate it. I use the
machine about once a week for half an hour or so at a time, I live in
Canada and my shop is unheated. The belt drive setup was originally setup
for a maximum speed of 500 RPM but I changed it so that it goes up to 1000
RPM because I came across a very similar Monarch lathe set up this way from
the factory.

I noticed it was low on oil and I was in a rush to fix my tractor so I
added 4 litres of 10W30 motor oil that I had on hand to get it to the
proper level. Is this ok or have I done something stupid?

stan