View Full Version : lubrication Oils
08-11-2001, 09:14 PM
I just bought an chinese combo milling/lathe. I'm sure there must be specialized lubrication oils to use while milling/latheing, but I have a bunch of used automotive oil. Is there any reason why this cannot be used??
08-12-2001, 05:26 AM
If it isn't too bad of shape it will work. I've drained some out before that I wouldn't want to use. Oil gets a lot of contaminates in it in the crankcase, lead etc. They warn about prolonged exposure you know, I've been exposed enough times.
Any oil is better than none as a cutting oil. I presume you are talking about cutting oil, don't put used oil in your oilcan and use as a lubricant. I have used used oil as a soak for rusty and stuck parts.
A good cheap source of cutting oil is Bacon Grease, works the best the old timers say. Might even give you an appetite. It doesn't seem to go rancid, the nitrates and the salt probably prevent it.
Have fun, watch your fingers and eyes, work safely.
08-18-2001, 12:06 AM
You should check your manuals to find out what weight of lubricant is required for your machine. Most Lubricats for machinery use the ISO viscosity rating. Do not put any gear oils in a gearcase unless you are absolutely sure no yellow metal (brass, bronze, copper, etc.) is present in the gearcase. If you put gear oil in a gearbox with yellow metal parts the extreme pressure additives will react with the yellow metal and damage the gearbox. Safer to stick to (AW) hydraulic or ATF fluids if you are not sure what your machine is supposed to use. Use a high quality way lubricant for dovetails, leadscrews, or linear bearings.
Do not use used motor oil for anything as it is considered toxic after use. Motor Oils are used for hydrodynamic lubrication and not for boundry layer or metal-to-metal contact.
An enormous amount of research goes into metal cutting lubricants and coolants - take advantage of that science and get the proper cutting fluid or coolant you need for the metals you work to achieve superior finishes. In the past many toxic subtances have been used out of ignorance - they really thought them safe...
If you're talking about cutting oil, almost anything you can slather on will probably help, some, but you can buy bulk "thread cutting oil" at a plumbing supply store or hardware store that is pretty cheap, and will probably work better.
If you're talking about lubricating oil, motor oil is NOT the thing to use in precision bearings. Motor oil is designed to keep water and dirt in suspension, so the water can boil out when the oil get hot and the dirt can be taken out by the filter. Neither of those conditions exist with a precision bearing. For the machine bearings at least, get real machine oil. If you can't find any, hydraulic oil of the proper viscosity is pretty nearly the same thing as machine oil.
08-21-2001, 03:04 AM
If you cannot find machine oil, you are not trying very hard. From the Big Boys you can get fossil based and some synthetic products. Amsoil makes full and partial synthetic lubes and are very high quality. They have a technical services department than can tell you if they have a suitable product or not. Email firstname.lastname@example.org or 715-392-7101
A R&O Gear & Bearing Lubricant is prefered for precision (such as class 7 Tapered) bearings. It will prevent damage to yellow metals (a regular gear oil cannot do this) and provide proper lubrication to bearings and gears (yellow metal, steel, or laminated composites). Hydraulic (AW & ATF) oils should only be used if you cannot obtain the proper lube for your machine.