Inneresting drilling: More Crisco, please....

Awl --
My buddy, an old-school machinist with a cupla old Hurco's, is making SS parts baskets for his heat treater -- constantly dipped in molten KCN.
He's spotting/drilling *thousands* of 5/16 holes in 1/8" 304 SS, first spotting with a 3/8 drill to get a bit of a c-sink.
Here's the skinny:
1. With soluble oil, carbide outperformed cobalt, but not by a lot. Not clear what grade the carbide was, or the cobalt -- just took whatever Traverse gave him. 2. With Crisco, the cobalt is outperforming the carbide *by a lot*. A lot-lot! And that includes a carbide drill I gave him, which I believe was good quality.
He says the side flutes of the carbide were actually wearing away.
Weird, eh? Suggests some kind of chemical/metallurgical interaction amongst the drill, Crisco, SS.
--

Mr. PV'd

Mae West (yer fav CongressShill) to the Gangster (yer fav Lobbyist):
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On Sep 8, 11:10am, "Proctologically Violated"

Has he compared Crisco against Moly-D? I think the toilet water was the weak link in the first test.
Later,
Charlie
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wrote:

Has he compared Crisco against Moly-D? I think the toilet water was the weak link in the first test. ====================================== No, and he proly won't. But the point of the ditty was the peculiarity (to me) that cobalt would outperform carbide under *any* circumstance.
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Mr. PV'd

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On Sep 8, 1:17pm, "Proctologically Violated"

It's got more "spring". Carbide drills aren't right for every application.
Later,
Charlie
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wrote:

Define "outperform".
The point of using carbide isn't better tool life, it's much faster cycle times.
If you aren't doing a production job on an expensive CNC machine, then carbide probably isn't worth the extra expense. But it easily pays for itself in production.
Also, in stainless, especially in grades like 304 and 316, you can't just use any old carbide drill and get good results. You need a pvd coated micrgrain carbide with the right grind, etc. Then you need a rigid set up and have to run the proper speeds and feeds. Otherwise you're just wasting your time.
As for the coolant, try Blaser Vascomill 22 cutting oil on the stainless. It's a vegetable based neat cutting oil and it outperforms anything I've tried to date in stainless and Ti.
--

Dan

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D Murphy wrote:

Dan:          Vegetable based cutting oil? You mean like Crisco?
    Sorry, couldn't resist. <g>
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Well yeah. That's why I mentioned it. But the Vascomill has additives and can be pumped through the coolant system. Plus it's waaay more expensive. LOL.
How you doin these days?
--

Dan

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D Murphy wrote:

Dan:
    Does it smell like a Burger King in the shop when doing a heavy face mill cut?

    Just cruising along. Tryin' to stay out of here for the most part. Hard habit to break cold turkey.
    I thought I read that there was an increase in machine tool sales in Aug. Have you guys noticed that?
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They put some nasty vanilla like fragrence in it that overpowers anything else. But once the fragrence dissipates it smells a little like a deep fryer.

We did but it's all reletive. The machine tool biz is still at all time lows.
--

Dan

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On Tue, 8 Sep 2009 14:10:33 -0400, "Proctologically Violated"

I do SS all day, every day, (303,304,316,17-4) and I haven't found a carbide drill that was worth spit. Cobalt is all I buy. Find the right speed and feed and they last and last. I use Hangsterfer's coolant at about 10% concentration. For larger holes where an insert drill can be used I have the best luck with Sandvik, their coatings are great. Some milling inserts they make go all day with no coolant on 303.
Bill Smith
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Amazing............just amazing. Imagine.....we are just now learning......again ....... what every apprentice learned in his apprenticeship....in 1900....animal fat as a cutting fluid. It's called lost knowledge and that subject was the life-long hobby of Isaac Asimov for those inclined to do some reading. Here is another, use lamb fat on your rotary file when cutting aluminum....the teeth won't fill with chips. Steve

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Yeah, except Crisco isn't animal fat.
Before you pontificate, get a clue.
Doug White
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I've been watching for some kind of answer but it doesn't look like one has shown up yet. Also, you didn't say whether your buddy was running both at the same speed or what.
I don't think I've ever drilled SS with carbide, so this isn't the voice of experience, but making the assumption that you're running both at the same speed, and that the cobalt HSS isn't burning up, he's running the carbide too slow to get the best productivity out of it. If he's running each at the recommended surface speed then he's drilling a lot faster with the carbide, and tool life isn't necessarily going to be a great deal better with the carbide.
As for the properties of the coolant versus the Crisco, coolant is nowhere near as good a lubricant as straight oil, but I have no idea how Crisco qualifies as a cutting lubricant. <g>
To get down to something that makes sense, what are the speeds at which he's running these two different bits? And just what do you mean by "outperforming"?
-- Ed Huntress
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On Wed, 09 Sep 2009 14:46:20 -0400, Ed Huntress wrote:

Well, I've used lard on aluminum; Crisco should be about the same.
But I can't vouch for its usefulness on SS. I once drilled a 3/8" hole in a 3/8 thick plate of 304, but IIRC, I used ordinary cutting oil. The bit was an ordinary HSS bit, sharp, of course, and the 304 cut like butter.
Cheers! Rich
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Maybe. Lard is lard oil + stearin; we know that lard oil has the right balance of high-pressure lubricity and film-puncturability (is that a word? <g>). I don't know about Crisco. The stearin in lard actually gets in the way by reducing the ability of the oil to flow. The hydrogenation of Crisco may do that, too, but I've never seen anything about it.
VW and many European companies use a form of peanut oil. We know that works, too, although the only applications I've heard of are mist-lubricated in high-speed machining.

When I was involved with a shop in Princeton I drilled several thousands holes in cylindrical 304 parts, on a Herbert turret lathe. My arms almost fell off, but the HSS drill bits we were using lasted through a lot of holes.
-- Ed Huntress
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Peanut oil apparently has one of the highest boiling points of the natural oils. We used to use it for reflowing the solder plating on RF circuit boards for a satellite I worked on. The technique for digital boards was to use heat lamps, but with the heavy ground planes of an RF board, they would either warp or scorch before the solder reflowed properly. A quick dip in peanut oil heated above the melting point of the solder produced a beautiful shiny solder plating, with no warping at all.
And they smelled yummy...
Doug White
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One of the things I remember from reading the first press releases about it, that I received from VW, was that the shop smelled really nice. <g>
Peanut oil is a very high-temp vegetable oil (it's the best for woks) but I don't know about its other properties as they relate to metalcutting. I'm getting a little vague about the details after 20 years or so but the ideal is some combination of high film strength but with a distinct threshold, in terms of force per unit area required to puncture the film, that allows the cutting edge to penetrate but for the rest of the contact area to be lubricated. Lard oil has it, as do some vegetable oils, but I don't know which ones. Mineral-based oils made for cutting are distinctly different from motor and machine oils.
I recall that I was suspicious of the descriptions because they didn't seem to be backed by much research, at least when I was covering cutting fluids in the metalworking press. It is a subject that has been taken up in tribology or metalcutting, somewhere, but I wasn't following it all by the time I saw references to the studies. Until the advent of synthetic cutting fluids, most of it was just based on informal experience.
Synthetic cutting fluids work in a different way from oils. And water-miscible oil coolants ("soluble oil") are just oil suspended in water. They're designed for cooling with moderate levels of lubrication, depending upon how "rich" you mix the coolant.
-- Ed Huntress
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I have tried drilling some stainless flatware and I am going to try the Crisco, as the regular cutting oil did not seem to help.
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On Wed, 9 Sep 2009 17:56:11 -0400 in rec.crafts.metalworking, "Ed

Also, new Crisco is not the same as old Crisco. Old Crisco was partially hydrogenated vegetable oil. Currently Crisco is a mix of un-hydrogenated oil and fully hydrogenated oil, to eliminate trans- fats.
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wrote,

Does this mean that, if you use it for a metalcutting lubricant, your machine won't develop hardening of the arteries?
<sigh> There is some strange quirk in the RCM emotional makeup, which I've never seen elsewhere in 35 years of visiting machine shops and plants, that abhors the idea of buying a fluid that's formulated for the purpose for which they're going to use it. I appreciate the joys of discovering something that's sold for some other purpose and that winds up being scads cheaper -- my barbecue baster is a 99-cent Chinese bristle brush screwed to a piece of scrap trim that Home Depot was giving away -- but this is fairly serious business. What makes anyone think that automatic transmission fluid, bacon fat, vegetable shortening or <shudder> used crankcase oil is going to have the right properties for good, safe, efficient, and effective machining? And how much are you going to use, anyway, in hobby machining? My Buttercut tends to go rancid before the can is empty.
This is the only place I've ever heard of it. The reasons for not using stearin-entrained lard oil (bacon fat, lard) and for not using oils formulated as machine lubricants, have been known for 100 years or more. If people actually did comparisons between real cutting oils and some of the slop that's discussed here, I think things would be different.
Some of it may be the lack of easy availability for traditional cutting oils -- lard oil, sulfated lard oil, chlorinated oils, and mineral oils actually formulated for cutting. 30 years ago I could walk into either of two stores nearby, an old-fashioned hardware store in town and a mill supply five miles away, and buy a small can of Buttercut or DoALL sulfated mineral oil. No more.
-- Ed Huntress
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