Michael,
There are many reasons not to use automotive oils to lube machinery. Don't do it. Vactra 2 68cST for gears, gibs and ways. Vactra
1 32cST for spindles. Viscosity can be measured in several ways. The viscosity tests are not the same and so not comparable, but
SAE oils are for automotive engine use only. Machinery oils are usually rated in Saybolt or the ISO standard.
Steve


"Michael Koblic" wrote in message ...
LMS recommends Mobil 1 for lubricating mini-mills. I picked up a bottle of 5W-30 and have been using it. I noticed that the oil
does not stay on the dovetails very long and tends to pool on the bench.

In my simple mind I thought: Higher viscosity is needed, something like 20W or so. That is where I got confused: I looked up the
figures for Vactra 2 (being the industry standard for ways etc.). Its kinematic viscosity at 40 deg C is 68 cSt (ISO68). When I
looked at the 5W-30 the viscosity was almost exactly the same. I thought this might be an error on the Mobil page but no, a
similar result came up for 5W-20. To puzzle me further, the 10W-30 is somewhat thinner at this temp.

The tables at my disposal suggest that the 5W oils should be under 20 cSt at 40.

Before all this I bought a bottle of 15W-50 which was on sale locally. According to the tables it should be somewhere near 45
cSt but according to the Mobil product sheet the 40 deg C viscosity is a whopping 131 cSt - about half way between Vactra 2 and
Vactra 4.

What am I missing here? Is this comparison at all valid?

--
Michael Koblic
Campbell River, BC