"Ed Huntress" wrote in message
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"John R. Carroll" wrote in message
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"Ed Huntress" wrote in message
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"John R. Carroll" wrote in message
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"Ed Huntress" wrote in message
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"Ignoramus20251" wrote in
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I personally disagree with bashing of flood coolant as used on
lathes. (and, granted, I do not have much experience).


OK, let's explore this,

Let's not and say we did Ed.
LOL
One thing your analysis omits is the lazy factor, if you want to call it
that, especially in a HSM environment.


because this is the heart of what I'm talking about.
This is where carrying over production practice to hobby practice can
result in misconceptions.

Yes, a stream of fluid will flush chips and greatly improve drilling and
tapping. Through-hole flushing is best, but a well-directed stream helps a
lot if the holes aren't too deep, even without through-hole flushing.

But that's NOT because it's coolant. It's because it's fluid. As you know,
gun drilling in difficult material was (maybe still is) done with
through-hole flushing of oil, not coolant. Oil is a much better lubricant
and it will give better performance in most cases.

OK but I've seen a lot of guys ruin a drill when the squirt bottle runs ot a
half inch before the hole does.


However, it's expensive; modern cutting tools often don't need it (as many
don't need, or benefit from, cooling); and it's a mess when applied as a
flood in production. Anyone who has been around a gear-hobbing production
operation that uses a flood of oil lubricant knows all about it. I used to
go through a pair of leather-soled shoes every few months when I was
covering gearmaking. g

In a hobby operation, most people don't have a sump, a pressure coolant
system, and flex nozzles. They don't have through-hole tools with glands
and pressure fittings. But some get the idea that it's the coolant that's
the issue here, when the fact is that coolant is just a lot cheaper and
leaves somewhat less slime on the floor. And it creates some problems that
you don't have with oil, which matter in production but not in a hobby
shop.

I've never seen a lathe without a sump or a pan so you have me there.


A travelling shield ( on the cross slide) and a coolant stream are worth
the trouble.

As for tools benefitting from it, what kinds of tools, run at what surface
speeds?

HSS or indexable uncoated carbide turning tools


Again, let's separate the layer-cake exotic coated carbides, CBN, ceramics,
coated diamond and so on that you may be using in your commercial
operation, often with radiused edges that we could barely get to cut in our
old (or Chinese) machines, from the HSS and plain grades of carbide used in
the typical hobby shop. This is, after all, RCM, and this kind of basic
info is of greatest interest and use to hobbyists.

In general, in commercial machining, tool life is a minor factor in the
production cost equation, as you know. In a home shop, it's a very big
deal. Oil will, in most cases, give longer tool life under hobby-shop
conditions than will water-miscible oil. We don't need cooling unless
we're pushing the envelope for maximum production rates. We need
lubrication to protect tool edges and to reduce cutting forces, partly to
get the most out of the feeble horsepower our old machines have and partly
to minimize the spring of those old machines, like my South Bend 10L.

Exactly, and soluble oil (lard based) is probably what I'd be using.
Can you still get that sruff?


You mention improved surface finish with flood coolant. Again, compared to
what? At what speeds, and with what kind of machines? Most hobby
machinists use a brush or drip lubrication. If we have the luxury of
pressure lubrication, we may get better finishes with flood *coolant*
(although I doubt it -- try using some modern mineral-based oil on the
same job some time), but it's NOT because we're using coolant. It's
because we're using pressure to get fluid into the cut interface a little
better than you can with drip or by brushing ahead of the cut.

Consistency counts Ed. A coolant stream at low preassure that doesn't need a
third hand is going to give a better result overall because it's consistent.
Oil that isn't brushed on appropriately isn't much good.

I had a guy instruct me on the fine art of facing, drilling and then
tapping pillar supports once. I'd finished fifty of the things without a
hitch by the time he'd realized the joke was on him.
Shall I tell a story or sing a song?
LOL

I'm not sure I'm following you, but it sounds like a production story. I
don't think I've ever made 50 of anything in my home shop.

Mold shops don't do production anything Ed, at least they didn't in those
days.

JC