Used motor oil as cutting fluid

Many years ago in the infancy of "The Home Shop Machinist" there was a recipe for soluble oil. I don't remember the proportions, but essentially you made up a fairly concentrated detergent solution and slowly added the oil to it. The other way around didn't work. If you added the detergent to the oil it wouldn't mix. I tried it and it worked OK. Easier to just buy the stuff today.

I had seen a way to cleanse used motor oil somewhere on the web. You needed two jugs, a thick rope and something to set the one jug higher than the other. It was like a siphon. You dipped the rope in the dirty oil jug, which was higher than the empty jug, and put the other end of the rope in the clean jug, supporting the rope in the middle with something so it didn't touch the sides of either jug. Wait 6 months until the oil wicks into the lower jug, cleaned of impurities by the rope and settling in the higher jug. I didn't try this one. I'd be interested in knowing if it works from someone who may have tried it.

RWL

Reply to
GeoLane at PTD dot NET
Loading thread data ...

================ Try using water pump lube from the autmotive section. Works for me.

Reply to
F. George McDuffee

Or try something really novel -- a fluid that's made for the job. A gallon of Trim Sol or similar water-miscible oil will cost around $20 - $25, and it will last you a very long time. For most machines that have a sump, you mix it somewhere around 10:1 with water.

If you use a good grade of cutting fluid (Trim Sol is well-tested in industry), you'll save enough on cutting tools to pay for it in no time. I had a quart of Trim Sol and it lasted me three or four years. And I did a heck of a lot more machining in those days. I mixed it 5:1 for use on my South Bend.

-- Ed Huntress

Reply to
Ed Huntress

Is that the kind of fluid that looks like fat free milk?

i
Reply to
Ignoramus14891

After it's mixed with water, yes, it's milky. That's your basic "water soluble" (actually, miscible), oil-based coolant, which has been around for more than 50 years. Some of the newer synthetics don't get milky -- and they really are water soluble, rather than miscible.

For the small shop, the basic miscible coolants are all you'll need. The fancier stuff can pay off at high speeds with multi-coated tools, but we're not likely to see their benefits in non-production applications.

Again, though, all of these water-diluted fluids should be thought of as coolants, not as cutting lubricants. Miscible oils are not as good at lubricating as the lard-oil and mineral-oil-based cutting oils. But they're close. Mixed 5:1, they're lousy coolants but better lubricants. That 5:1 mixture for my South Bend was recommended to me by the engineers at Master Chemical, who make Trim Sol. If you apply your cutting lubricant with a brush or with a drip, you're really after lubrication rather than cooling. If you need cooling, you need a mist or a jet. That's when you use the regular dilutions.

-- Ed Huntress

Reply to
Ed Huntress

=========== What a novel idea!!!!

For home/hobby shop use, where the standard black sulphur oil is too thick and you want/need some cooling effect, try diluting the black sulphur oil with mineral spirits paint thinner [varsol]. The varsol will evaporate quickly cooling the tool, the sulphur will help avoid chip welding/edge build up and the oil will provide enough lubrication.

formatting link
To minimize spilling, a heavy pipe cap makes a good coolant cup for typical home shop solder/flux brush application.

How many people have and use a coolant pump/sump setup? Some how this seems like overkill for the home/hobby shop.

also see

formatting link
Be reminded that none of these are "magic" and will not compensate for a tool that needs grinding, bad headstock bearings, loose gibbs, excessive chip loads/feeds, etc.

Reply to
F. George McDuffee

I do. I started with a 1-gallon Little Giant flood-cooling pump, for the drill press. What a difference that made.

I considered the Little Giant for the Millrite vertical mill, but the table doesn't have a drain fitting, and I figured that flood would be far too messy.

I started with a cheap mister with one control, but it filled the shop with drifting clouds of mist. I changed to a two-control mister (Noga), which works much better. I move this mister between mill and Clausing lathe at present. It is slightly messy, but does work. One fine day I'll get a second mister.

Joe Gwinn

Reply to
Joseph Gwinn

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.