Machine tools and automotive lubricants 1

[strokersix]

I know the safe bet is to use the lubricants recommended by the machine tool manufacturer. However, I've used motor oil for years in my milling machine and lathe. Lighter weight in the milling spindle and 50W racing oil most everywhere else.

I've been told that using detergent oils in a geared head lathe could loosen old crud deposits and recirculate them. This I can believe.

I'm having a hard time believing automotive lubricants will cause harm to roller bearings, gears, and slideways which are continuously supplied with clean oil, excess runs out and is wiped up. Next time I place an order I will get proper lubricants but in the meantime I'm curious. What exactly is the problem with motor oils for machine tool lubricant other than the above mentioned oil bath geared head example?

 

[evelrod]

I not much of a machinist so my solution may be worth what it will cost you to read it....
I just use my Redline 50 from the race car. I use it for just about everything from my air compressor to waterproofing my boots! ;o)
It's not exactly "free" but, better than dumping it in the recycle barrel after each weekend. I'd use it in my vintage cars if it was "street" compatible.

Rod

 

[EdDanzer]

I have used motor oil in manual machine tools for years without any problems.

Ed Danzer

http://www.danzcoinc.com

http://www.dehyds.com

 

[romke]

there are two important distinctions between machinetool oil and engine oils.

the first is the water shedding property - machinetool oils are good at this, engine oils are not. watershedding is important because you do not want your machining fluid contaminated with engine oil since this can lead to the growth of bacteria and a very unpleasant smell of the machining fluid.

the second difference is frictional characteristics. way/machinetool lubs contain anti-stick slip components to enhance machining accuracy, engine oils do not.

you may get away with engine oil when machining dry and utmost machining accuracy is not needed - if highspeed machining is called for you will have to take care of your machining fluids and use dedicated lubricants - that usually are far cheaper then engine oils because they contain less and less complex additives.

the lubrication of gears and bearings is no problem, engine oils usually exceed the capabilities of most machinetool oils in this respect

 

[rmw]

I got the impression that the OP was using the motor oil in the gear boxes on the tools, not as a cutting fluid. Am I wrong?

rmw

 

[evelrod]

rmw, that was my impression.

I use a water soluble oil for cooling.

Rod

 

[strokersix]

Well both actually. Probably violating many accepted lubricant thumb rules. My original question was use of motor oils for lubricating rolling and sliding elements of machine tools exclusive of geared heads with a sump.

I do actually use kerosene, motor oil, and "xtra thick" cutting oil and mixtures thereof for cutting tool lubricant. For example, for stainless I use the special "xtra thick" straight. For aluminum I use a mix of kerosene and motor oil. My oil can usually has a mixture of "xtra thick" and motor oil for general purpose steel cutting lubricant. There may be faults in my methods so please don't take this as expert advice!

I have observed that when I first get a used machine tool I clean and lubricate throughly and the oil running off clearly carries lots of crud with it. Then over time it gets cleaner until oil running off remains fairly clean. Whether this is evidence of motor oil detergent action or if plain machine oil would do the same thing I don't know, I've always used motor oil.

 

[romke]

the cleaning action you observe is the effect of the detergent/dispersant package in the engine oil. standard industrial gear oils do not have these additives in them.