Oil viscosities


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?
Reply to
Michael Koblic
Loading thread data ...
Wouldn't it be easier to compare viscosities of single grade oils, also not sure why you would use a motor oil to lubricate non-combusting machinery, you're getting a ton of additives along with some viscosity ranges suited to temperature extremes that seem to me anyway, inappropriate to lubricate machinery.
Reply to
Jeff D.
Automotive detergent oil will screw up the felt wicks that are used in many machines. It will make them stiff and move the oil. Also the detergent oil will tend to carry the grit in suspension rather than letting it settle out.
The Vactra way oils have an additive to make the oil adhere to the ways, the same function as the additive in chainsaw bar oil. Vactra 2 is what is mostly used on ways.
John
Reply to
john
Lucas brand synthetic gear oil stays put , lubes well , and is available almost everywhere (well , everywhere in the USA) . I use it on leadscrews , ways , gears , and countershaft bushings on my mill and lathe both . Kinda pricey though , about 7-8 bucks a quart .
Reply to
Snag
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
5W-30 and have been using it. I noticed that the oil
so. That is where I got confused: I looked up the
kinematic viscosity at 40 deg C is 68 cSt (ISO68). When I
might be an error on the Mobil page but no, a
thinner at this temp.
According to the tables it should be somewhere near 45
whopping 131 cSt - about half way between Vactra 2 and
Reply to
Steve Lusardi
Vactra 1, 2 and 4 have tackifiers that help it stay adhered to the ways.
From what I've been told Vactra 4 is for vertical column machines.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
Reply to
Wes
Do you happen to know what is the chemical nature of the said tackifiers? It might help when determining what is the nearest equivalent of Vactra locally. It is not immediately relevant but might become so in the New year.
Reply to
Michael Koblic
One thinks that molassas is a major component. I spelled about a quarter ounce of Vactra 2 today..and it took about 5 minutes and a dozen really good spritzs of WD40 to get it off the area Im going to be painting tommorow.
Gunner
"I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. In my youth I travelled much, and I observed in different countries, that the more public provisions were made for the poor the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer." -- Benjamin Franklin, /The Encouragement of Idleness/, 1766
Reply to
Gunner Asch
I don't know what the tackifier is. KBCtools.com which has operations in Canada has a product called EEZ Way oil. Various weights are listed. Calling them might be a good idea. Sadly, McMaster-Carr doesn't ship to Canada obtaining small amounts of vactra would be easy.
Wes
Reply to
Wes
Dealing with the Vancouver branch of KBC tools has its drawbacks. I generally try to avoid them if I can. There is a local office of Shell Canada with helpful staff whom I would probably approach if it became relevant. Or I could use the doughnut method someone suggested in the past :-) Either way I thought it would have been useful to know a little more of the actual science involved. But not essential...
Reply to
Michael Koblic

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.