Inneresting drilling: More Crisco, please....

I'm sure that's some of it, as I suggested in my last paragraph. But this is basic stuff for machining. I would think that someone who is machining on a regular basis would keep some on hand, and would anticipate needing it pretty accurately.

I used to buy Buttercut in one-pint cans. Applying it with a squirt container, a pint lasts through a lot of home-shop machining, unless you have big and modern machines in your home shop. Most of us don't.

It's still available online. The problem here is the disappearance of neighborhood mill supply stores. Even in Princeton, New Jersey, I used to be able to buy it in an old hardware store that was right across the street from the university. And it was available in the little commuter town I live in now until the mid-'80s. Every mill supply used to carry a variety of DoALL products, including their cutting oils and cutting wax for use on bandsaws.

Perhaps. It's too bad, because the real stuff is a lot better.

That's true, but a few fluids will handle most work much better than the makeshift oils and other gunk some people use.

Uh, the original Tap Magic, the basic stuff made for use on steel, would eat aluminum, turn it black, and send off fumes that would like to knock you out. I still have a half-can of it. But I know what you mean. Two types of Tap Magic would handle almost everything.

True. But that's what we're stuck with.

If they paid better at the hobby magazines, I'd give it a try. But they once offered me $25 for an article at HSM, and I told them I don't take the cover off my Selectric for $25. Obviously, that was a while ago.

As for the re-packaging, it's an idea I've had for 30 years. A lot of people have, based on my conversations with many other people who have specialty interests like this. A friend of mine followed the model I was talking about and now runs a successful little art-supply business based on it.

The first step is to start calling cutting-fluid manufacturers and ask them. Then call the big cutting tool makers and ask *them*. That's the way I'd approach such an article when I was making a living at it. It will save you a lot of speculative research.

-- Ed Huntress

You may find this old book, "Cutting Lubricants" from 1914 of interest. See:

"A cheap lubricant for turning which has been extensively used is made in the following proportions: 1 pound of sal-soda (carbonate of soda), 1 quart of lard oil, 1 quart of soft soap, and enough water to make 10 or 12 gallons. This mixture is boiled for one-half hour, preferably by passing a steam coil through it. If the solution should have an objectionable odor, this can be eliminated by adding about 2 pounds of unslaked lime. The soap and soda in this solution improve the lubricating quality and also prevent the surfaces from rusting..."

Man, that's a good one, Leon. It's old info but it should be useful to anyone using older, low-horsepower machines and HSS tools today.

Note that they say one of the quickest ways to wreck a high-speed tool is to dip it in water when you're grinding. There have been several arguments about that here. I agree with the book.

Also, the water-based coolants are important when you're going for productivity in a commercial shop, but they shouldn't mean much to 90% of hobby machinists who use light machines, HSS tools, and who are machining for fun.

-- Ed Huntress

I think Mobil Exxon is one of the real biggies in oils and sure enough both W.W. Grainger and MSC carry Mobilmet cutting fluids and the price is reasonable at $16.xx per gallon for Mobilmet 404 and Mobilmet 766. A lot better buy than some of the cutting fluids at $16.xx per pint. And good for me as they both have stores that are local to me.

So looked at the MDS for both of them and found something interesting. Less than 3% of DMSO in both of them. Tried looking at the MDS for ButterCut and only found that it was made of all natural materials.

Mobil also has a high sulfur oil Mobilmet Omega which is slightly more expensive at $22.xx per gallon

The Mobilmet 404 is interesting in that the MSC catalog says " may be used as a cutting oil, a lubricating oil, and in moderate- duty hydraulic systems and airline oilers."

So does anyone have any experience with any of these cutting fluids?

Dan

When I took a machining course many years ago ( but not when that book was published ), the instructor showed how to grind a HSS bit free hand on a bench grinder. I can not remember if he used water or not, but I am pretty sure he did not caution against it. So for years I have been cooling tool bits in water when they are too hot to hold in my bare hands. I lean into it when rough grinding and they do get hot when you are shaping a new bit. Anyway I have never had any bits wrecked by doing that. Agreed there might be some microcracks, but I figure they are ground off when I use the fine wheel after rough grinding.

Anyway has anyone actually experienced a hss tool bit being wrecked by dipping in water? Or has the technology improved bits so it is not a problem. It isn't as if I have ground thousands of tool bits. I just have not seen a problem with the ones that I have ground.

Dan

You just dont want the tool steel to get so hot that it becomes discolored.

If the tool gets hot enough to start changing colors, then its hardness and temper can be lost. Let it cool slowly and it'll anneal. Quench it, and it can get glass hard and glass fragile. This happens most right at the point of a tool where there's not so much mass. It's often worst on drills, or other tools whose point sections and cutting edges are thin to start with.

If the tool does change color while grinding, just a finishing pass won't fix it. You pretty much have to remove the whole affected section (without heating it up again) and then reshape it from there.

I've never seen a tool fracture or die outright from grinding or quenching; but I've seen plenty that wear instantly when put back to work, either because they're softer than they used to be, or brittle and prone to crumbling at the edges.

There's nothing wrong with water to cool a tool while working on it. Just cool it often, thoroughly, so you're not adjusting the metallurgy at the same time you're touching up the cutting edge.

KG

That is only true if it achieved austenitizing temperature, which on HSS would be over 1800 (more like 2000+) which is nearly white hot. You're probably just going to soften it if you get it too hot.

It is only an issue if you're exceeding the tempering temperature, which for M2 HSS is over 1000. As long as you're not getting it red hot, you should be fine. However, it is possible to get a thin cutting edge red hot for a moment and not notice - so you still need to take care. But I wouldn't worry about a little heat color while grinding HSS.

If you notice the cutter is softer after grinding, you probably got it a bright red hot at the very cutting edge. You might want to dress you grinding wheel - it might be glazed.

Not high-speed steel, Kirk. The highest temperature represented by oxidation colors is around 650 or 700 deg. F. That's "steel gray," beyond blue. HSS can be used at up to 1050 deg. F or so. (Most M50 can't take it, because it's mostly junk. But we don't use M50 for decent cutting tools. Mostly it's for Chinese drill bits).

It will hold its hardness and return to full hardness when cooled, even when it glows dull red.

Again, not HSS. It has a two-stage hardening procedure and what happens above 1050 F is not really annealing. You have to run up to around 1650 for that.

It will not harden more from simple quenching in that way. It *will* get stressed to the limit, and maybe beyond. It will develop microcracks and it will be prone to failure

Again, not HSS. That's true of carbon-steel, martensitic stainless, and alloy steels used for woodworking cutting tools and metalworking die and mold steels. But not metalcutting tools.

That's true of most die steels. But HSS can take the heat. It just can't take the quenching.

If you don't get it hot enough to show colors, most die steels and woodworking steels can take that. HSS is somewhat more sensitive to quenching than most other steels.

-- Ed Huntress

I bought a gallon of way oil quality Vactra - from MSCdirect. I also got a gallon of spindle oil. I got 10 gallons of hydrollic oil from the local oil/gas wholesaler. I got 5 gallons of lube oil from the same wholesaler.

I have 4 machines that use way oil.

Mart> "Ed Huntress" wrote in

FWIW, Scott Logan says he uses way oil for pretty much every part of his lathes except for the geared heads. I'm thinking he knows his stuff as far as his old iron, at least.

Yeah, and don't be a Hercules. Take a minute. Also, gash the relief last. It's quick, clean and doesn't generate a lot of heat.

The order of operations is always worth considering.

The one problem I have with old technical books lies in the lack of a good translation. Nowadays "soft soap" probably has a totally different meaning than it did in 1914 (now it's horribly-scented slime found in guest bathrooms across the nation). Usually when I see any old references to soap, my brain substitutes Fels-Naptha brown soap flakes (does it still exist?).

So what would be the meaning of soft soap in the above article?

Joe

Don't know where to get it, but this search will get you some info:

Fels-Naptha is still around, here is one source:

Ah, so "soft soap" is basically *real* soap, just more runny than bar soap.

Good ole Lehmans. A co-worker gave me one of their catalogs about 25 years ago; if they had a local store, I'd not need to haunt our flea market so much.

Thanks for the links, Leon.

Joe