Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without it
that the edge is dulled? I thought HSS & especially carbide could stand
the temperatures created by HSM work.

2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both? I'd like to fill in the
chart (my guesses shown):

Mild Cast Tool*
Steel Iron Steel Alum Brass

Lathe ? D ? ? D

Mill ? D ? ? D

Drill ? D ? K D
press

Band W D ? ? D
saw

C = coolant
L = lube
D = dry
K = kerosene or equiv
W = wax

* - actually I don't care about Tool Steel, as I never use it. It's
included for completeness

Thanks,
Bob

"Bob Engelhardt" wrote in message
...
Joe's recent thread about his dribble cooling for his lathe reminds me of
questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without it
that the edge is dulled? I thought HSS & especially carbide could stand
the temperatures created by HSM work.

It will. You can run HSS up to around 1000 deg. F -- a dull red glow.
Carbide can run much hotter. Most of us never see those temperatures on old
or small lathes. If you have a real industrial lathe, less than 40 years
old, you might want to think about cooling. Otherwise, lubrication is likely
to be more important, and cutting oil lubricates much better than coolant
does.


2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

It can reduce cutting forces and, yes, it reduces chip friction off of the
tool. It often improves finishes. It increases the life of cutting edges. By
reducing cutting forces, it can help stabilize the work temperature -- which
is the only worthwhile reason to run coolant on a small or old lathe.
Coolant does that job better.


3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both? I'd like to fill in the
chart (my guesses shown):

Mild Cast Tool*
Steel Iron Steel Alum Brass

Lathe ? D ? ? D

Mill ? D ? ? D

Drill ? D ? K D
press

Band W D ? ? D
saw

C = coolant
L = lube
D = dry
K = kerosene or equiv
W = wax

* - actually I don't care about Tool Steel, as I never use it. It's
included for completeness

Thanks,
Bob

Now you've opened a real can of worms. g

FWIW -- and only as an aside, because we don't usually use these tools in
HSM work -- really advanced multi-coated tools, diamond-coated tools, and
ceramic tools should NOT be run with coolant on a milling machine. Those
tools can't stand the repeated thermal shock. They're usually run dry, or
with a very lean mist.

--
Ed Huntress

In article ,
Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without it
that the edge is dulled? I thought HSS & especially carbide could stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips to
cutting tool, which causes effective dulling. The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.


2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. This usually results in better surface finish, and may yield
better accuracy as well.


3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both?

It mostly depends on the material being cut. This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. Plain water (used when machining some plastics) is a pure
coolant. Wax is a pure lubricant. Oil in flood is a lubricant with
significant cooling ability. Oil emulsion in water does both. And so
on. One can make a career of this.


I'd like to fill in the chart (my guesses shown):

Mild Cast Tool*
Steel Iron Steel Alum Brass

Lathe ? D ? ? D

Mill ? D ? ? D

Drill ? D ? K D
press

Band W D ? ? D
saw

C = coolant
L = lube
D = dry
K = kerosene or equiv
W = wax

* - actually I don't care about Tool Steel, as I never use it. It's
included for completeness

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007.

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages.

I will say that parts of this book are very heavy going.

Joe Gwinn

Naw. It doesn't really cool all that much. What it does is flash into steam and blows the chips
away..

Bob Swinney
"Bob Engelhardt" wrote in message ...
Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without it
that the edge is dulled? I thought HSS & especially carbide could stand
the temperatures created by HSM work.

2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both? I'd like to fill in the
chart (my guesses shown):

Mild Cast Tool*
Steel Iron Steel Alum Brass

Lathe ? D ? ? D

Mill ? D ? ? D

Drill ? D ? K D
press

Band W D ? ? D
saw

C = coolant
L = lube
D = dry
K = kerosene or equiv
W = wax

* - actually I don't care about Tool Steel, as I never use it. It's
included for completeness

Thanks,
Bob

On Jun 26, 1:35*pm, Bob Engelhardt wrote:
...
2. *What is the purpose of cutting oil? *I remember reading that it
allowed chips to flow off the cutting edge more easily. *Is that it?

Bob

I've noticed that drill bits sometimes cut a thicker chip for the
handle pressure after the oil is gone and the bit and work heat up. I
add more on the theory that oil helps prevent chip jams and breakage.
When the bandsaw blade is gets dull enough it will only cut completely
dry. Lube wax makes it skate.

jsw

A metalworking fluid perform several functions.

1. It is a great conversation starter
2. It cools the cutter
3. It lubricates the contact area where the tip of the cutter removes
material, and therefore less heat is generated. (not the same as 2.)
4. It prevents microscopic welding of material to cutter, thus
improving surface finish and effective sharpness of the tip.
5. For high speed machining, high pressure stream of coolant removes
chips. (not something we encounter with manual machines)

I would also like to learn when straight oil is more appropriate than
soluble oil.,

i

In article ,
Ignoramus10071 wrote:

A metalworking fluid perform several functions.

1. It is a great conversation starter
2. It cools the cutter
3. It lubricates the contact area where the tip of the cutter removes
material, and therefore less heat is generated. (not the same as 2.)
4. It prevents microscopic welding of material to cutter, thus
improving surface finish and effective sharpness of the tip.
5. For high speed machining, high pressure stream of coolant removes
chips. (not something we encounter with manual machines)

I would also like to learn when straight oil is more appropriate than
soluble oil.

Depends on the straight oil, depends on the soluble oil, depends on the
material to be worked. There are only 5,000 variations.

For drilling and countersinking and tapping stainless steel, black
sulfur oil is hard to beat, although WS-5050 does work.

Joe Gwinn

On Jun 26, 3:14*pm, Joseph Gwinn wrote:
In article ,
*Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. *What is the purpose of cooling? *Does the tool get so hot without it
that the edge is dulled? *I thought HSS & especially carbide could stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips to
cutting tool, which causes effective dulling. *The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. *With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. *What is the purpose of cutting oil? *I remember reading that it
allowed chips to flow off the cutting edge more easily. *Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. *This usually results in better surface finish, and may yield
better accuracy as well.

3. *Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? *Or both? *

It mostly depends on the material being cut. *This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. *Plain water (used when machining some plastics) is a pure
coolant. *Wax is a pure lubricant. *Oil in flood is a lubricant with
significant cooling ability. *Oil emulsion in water does both. *And so
on. *One can make a career of this.





*I'd like to fill in the chart (my guesses shown):

* * * * * * *Mild *Cast *Tool*
* * * * * * Steel *Iron *Steel *Alum *Brass

Lathe * * * *? * * *D * * ? * * *? * * D

Mill * * * * ? * * *D * * ? * * *? * * D

Drill * * * *? * * *D * * ? * * *K * * D
press

Band * * * * W * * *D * * ? * * *? * * D
saw

C = coolant
L = lube
D = dry
K = kerosene or equiv
W = wax

* - actually I don't care about Tool Steel, as I never use it. *It's
included for completeness

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. *There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007. *

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages. *

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry. ( http://tinyurl.com/l27kaq
) Does he use chemical explanations for the role of sulfur in helping
metal cutting operations? (sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows. Some reactions are fast and it
could be that surface chemistry is involved. Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

This book has a chapter on coolants and lubrication:
“Metal Cutting” by Edward Trent & Paul Wright: http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Ignoramus10071 wrote:

A metalworking fluid perform several functions.

1. It is a great conversation starter
2. It cools the cutter
3. It lubricates the contact area where the tip of the cutter removes
material, and therefore less heat is generated. (not the same as 2.)
4. It prevents microscopic welding of material to cutter, thus
improving surface finish and effective sharpness of the tip.
5. For high speed machining, high pressure stream of coolant removes
chips. (not something we encounter with manual machines)

I would also like to learn when straight oil is more appropriate than
soluble oil.,

I suppose its a tradeoff. A lubricant provides coolant and (as in your #3) a
coolant lubricates. The more heat you generate, the better the fluild's
cooling properties should be.

I'm also thinking about the use of a lubricant to reduce the load on the
workpiece/tool and resulting distortion. Cutting a thread by hand with oil,
for example, seems to produce a better result than without, as the tap (or
workpiece) doesn't twist as much. Its not a heat factor, as I can just go
slow enough to allow conduction to dissipate that. The ultimate in
distortion when not using oil is busting a tap off. But short of that,
anything that reduces the forces will result in a more accurate cut.

--
Paul Hovnanian
----------------------------------------------------------------------
Have gnu, will travel.

"Paul Hovnanian P.E." wrote in message
...
Ignoramus10071 wrote:

A metalworking fluid perform several functions.

1. It is a great conversation starter
2. It cools the cutter
3. It lubricates the contact area where the tip of the cutter removes
material, and therefore less heat is generated. (not the same as 2.)
4. It prevents microscopic welding of material to cutter, thus
improving surface finish and effective sharpness of the tip.
5. For high speed machining, high pressure stream of coolant removes
chips. (not something we encounter with manual machines)

I would also like to learn when straight oil is more appropriate than
soluble oil.,

I suppose its a tradeoff. A lubricant provides coolant and (as in your #3)
a
coolant lubricates. The more heat you generate, the better the fluild's
cooling properties should be.

I'm also thinking about the use of a lubricant to reduce the load on the
workpiece/tool and resulting distortion. Cutting a thread by hand with
oil,
for example, seems to produce a better result than without, as the tap (or
workpiece) doesn't twist as much. Its not a heat factor, as I can just go
slow enough to allow conduction to dissipate that. The ultimate in
distortion when not using oil is busting a tap off. But short of that,
anything that reduces the forces will result in a more accurate cut.

--
Paul Hovnanian
----------------------------------------------------------------------
Have gnu, will travel.

Maybe it helps to look at where these coolants come from. Cutting oils,
animal, vegetable, or mineral, are so-so lubricants with very high film
strength but poor film-puncture strength; they can take a lot of pressure
but they collapse entirely when you exceed their pressure threshold. Thus,
they lubricate moderately well except right at the cutting edge. With
moderate power (old machines; flexible machines), they reduce cutting forces
and non-cutting friction but the oil is a poor conductor of heat.
Lubrication is more important than cooling at low speeds and low power.

Miscible-oil ("soluble" oil, which isn't really soluble) coolants came along
to answer several issues in production manufacturing. One was cost; they're
much cheaper, since they're mostly water. Another was tool materials that
allowed higher speeds and the generation of more heat, along with higher
horsepower and much higher spindle speeds. Cooling passed lubrication as the
generally dominant need. Miscible oils cool well because of the water. They
lubricate well enough, although not nearly as well as straight oils. They
were cheap enough that you could drain them into central sumps and keep
large reservoirs of them without breaking the bank. In the old days, you
could dump them in the nearest stream when you were done with them and they
wouldn't leave much of a slick. g

Where cutting forces or non-cutting friction is high, you can add sulfur to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such as
tapping, benefit from the sulfur. You can also add chlorine or a variety of
other chemicals to get a somewhat mysterious reduction in shear strength at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the '50s.
Maybe they have it figured out now. They didn't when I was writing about it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength right
at the cutting edge. Don't use it.

And don't confuse water-miscible coolants with the newer synthetics. They
work by magic, or something like it. Or it seems that way to us
non-chemists. Somehow they produce combinations of reduced shear strength,
decent lubrication, and good cooling. They are not miscible oils, synthetic
or otherwise. They are magical chemicals.

Water-miscible oils are the common denominator today NOT because they
lubricate well, but because they became the industrial standard for many
types of machining by the '60s and they are readily available and still
relatively cheap. If you have an industrial machine and cutting tools from
that era or later, they're great. If you have older machines and if you use
a lot of HSS for turning and milling, particularly if your machine has low
spindle speeds, you're probably better off with straight oil -- sulfurized
or not, as you prefer. And, according to Doby Dave on AMC, they leave your
skin nice and smooth, and running sulfurized oil helps him keep his youthful
looks. g

--
Ed Huntress

Very nice missive, Ed. Thanx ! You failed to answer the suffur question but you do write well.
(just kidding) In actuality, I doubt if any one with the requisite chemistry and / or metallurgical
skills to explain the sulfur question would stoop to write in RCM. (That's a challenge . .
Eggheads !)

Bob (still likes the steam analogy) Swinney
"Ed Huntress" wrote in message ...

"Paul Hovnanian P.E." wrote in message
...
Ignoramus10071 wrote:

A metalworking fluid perform several functions.

1. It is a great conversation starter
2. It cools the cutter
3. It lubricates the contact area where the tip of the cutter removes
material, and therefore less heat is generated. (not the same as 2.)
4. It prevents microscopic welding of material to cutter, thus
improving surface finish and effective sharpness of the tip.
5. For high speed machining, high pressure stream of coolant removes
chips. (not something we encounter with manual machines)

I would also like to learn when straight oil is more appropriate than
soluble oil.,

I suppose its a tradeoff. A lubricant provides coolant and (as in your #3)
a
coolant lubricates. The more heat you generate, the better the fluild's
cooling properties should be.

I'm also thinking about the use of a lubricant to reduce the load on the
workpiece/tool and resulting distortion. Cutting a thread by hand with
oil,
for example, seems to produce a better result than without, as the tap (or
workpiece) doesn't twist as much. Its not a heat factor, as I can just go
slow enough to allow conduction to dissipate that. The ultimate in
distortion when not using oil is busting a tap off. But short of that,
anything that reduces the forces will result in a more accurate cut.

--
Paul Hovnanian
----------------------------------------------------------------------
Have gnu, will travel.

Maybe it helps to look at where these coolants come from. Cutting oils,
animal, vegetable, or mineral, are so-so lubricants with very high film
strength but poor film-puncture strength; they can take a lot of pressure
but they collapse entirely when you exceed their pressure threshold. Thus,
they lubricate moderately well except right at the cutting edge. With
moderate power (old machines; flexible machines), they reduce cutting forces
and non-cutting friction but the oil is a poor conductor of heat.
Lubrication is more important than cooling at low speeds and low power.

Miscible-oil ("soluble" oil, which isn't really soluble) coolants came along
to answer several issues in production manufacturing. One was cost; they're
much cheaper, since they're mostly water. Another was tool materials that
allowed higher speeds and the generation of more heat, along with higher
horsepower and much higher spindle speeds. Cooling passed lubrication as the
generally dominant need. Miscible oils cool well because of the water. They
lubricate well enough, although not nearly as well as straight oils. They
were cheap enough that you could drain them into central sumps and keep
large reservoirs of them without breaking the bank. In the old days, you
could dump them in the nearest stream when you were done with them and they
wouldn't leave much of a slick. g

Where cutting forces or non-cutting friction is high, you can add sulfur to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such as
tapping, benefit from the sulfur. You can also add chlorine or a variety of
other chemicals to get a somewhat mysterious reduction in shear strength at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the '50s.
Maybe they have it figured out now. They didn't when I was writing about it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength right
at the cutting edge. Don't use it.

And don't confuse water-miscible coolants with the newer synthetics. They
work by magic, or something like it. Or it seems that way to us
non-chemists. Somehow they produce combinations of reduced shear strength,
decent lubrication, and good cooling. They are not miscible oils, synthetic
or otherwise. They are magical chemicals.

Water-miscible oils are the common denominator today NOT because they
lubricate well, but because they became the industrial standard for many
types of machining by the '60s and they are readily available and still
relatively cheap. If you have an industrial machine and cutting tools from
that era or later, they're great. If you have older machines and if you use
a lot of HSS for turning and milling, particularly if your machine has low
spindle speeds, you're probably better off with straight oil -- sulfurized
or not, as you prefer. And, according to Doby Dave on AMC, they leave your
skin nice and smooth, and running sulfurized oil helps him keep his youthful
looks. g

--
Ed Huntress

In article
,
"Denis G." wrote:

On Jun 26, 3:14*pm, Joseph Gwinn wrote:
In article ,
*Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. *What is the purpose of cooling? *Does the tool get so hot without it
that the edge is dulled? *I thought HSS & especially carbide could stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips to
cutting tool, which causes effective dulling. *The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. *With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. *What is the purpose of cutting oil? *I remember reading that it
allowed chips to flow off the cutting edge more easily. *Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. *This usually results in better surface finish, and may yield
better accuracy as well.

3. *Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? *Or both? *

It mostly depends on the material being cut. *This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. *Plain water (used when machining some plastics) is a pure
coolant. *Wax is a pure lubricant. *Oil in flood is a lubricant with
significant cooling ability. *Oil emulsion in water does both. *And so
on. *One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. *There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007. *

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages. *

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry. (http://tinyurl.com/l27kaq) Does he use chemical explanations for the role of sulfur in helping

It's quite the tome. Although it did scratch the itch, it was far more
than I wanted to know. Glad I got it from the library.


Does he use chemical explanations for the role of sulfur in helping metal
cutting operations? (sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows.

This was a big question, for exactly that reason. It turns out that the
effect *is* chemical. The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has a
lot of chlorine.

I assume that research continues, if only because the perplexing and
counter-intuitive behavior interests people, especially university
professors.


Some reactions are fast and it
could be that surface chemistry is involved. Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. Sulfur and chlorine rule.

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not, or
there would be a lot of freon-based cutting fluids.


This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright: http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have such
large coolant flows.

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article
,
"Denis G." wrote:

On Jun 26, 3:14 pm, Joseph Gwinn wrote:
In article ,
Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds
me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without
it
that the edge is dulled? I thought HSS & especially carbide could
stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips
to
cutting tool, which causes effective dulling. The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. This usually results in better surface finish, and may yield
better accuracy as well.

3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both?

It mostly depends on the material being cut. This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. Plain water (used when machining some plastics) is a pure
coolant. Wax is a pure lubricant. Oil in flood is a lubricant with
significant cooling ability. Oil emulsion in water does both. And so
on. One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007.

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages.

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry.
(http://tinyurl.com/l27kaq) Does he use chemical explanations for the
role of sulfur in helping

It's quite the tome. Although it did scratch the itch, it was far more
than I wanted to know. Glad I got it from the library.


Does he use chemical explanations for the role of sulfur in helping metal
cutting operations? (sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows.

This was a big question, for exactly that reason. It turns out that the
effect *is* chemical. The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has a
lot of chlorine.

I assume that research continues, if only because the perplexing and
counter-intuitive behavior interests people, especially university
professors.


Some reactions are fast and it
could be that surface chemistry is involved. Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. Sulfur and chlorine rule.

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not, or
there would be a lot of freon-based cutting fluids.


This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright: http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have such
large coolant flows.

Joe Gwinn

When you get into really high-speed cutting, Joe, they often run dry -- or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.

BTW, I had lunch with Milton Shaw, back in the mid-'70s. We used his work
for several technical articles at _American Machinist_, 'way back when.

--
Ed Huntress

On Jun 27, 3:45*pm, Joseph Gwinn wrote:
In article
,
*"Denis G." wrote:







On Jun 26, 3:14*pm, Joseph Gwinn wrote:
In article ,
*Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds me
of questions that I have.

1. *What is the purpose of cooling? *Does the tool get so hot without it
that the edge is dulled? *I thought HSS & especially carbide could stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips to
cutting tool, which causes effective dulling. *The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. *With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. *What is the purpose of cutting oil? *I remember reading that it
allowed chips to flow off the cutting edge more easily. *Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. *This usually results in better surface finish, and may yield
better accuracy as well.

3. *Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? *Or both? *

It mostly depends on the material being cut. *This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. *Plain water (used when machining some plastics) is a pure
coolant. *Wax is a pure lubricant. *Oil in flood is a lubricant with
significant cooling ability. *Oil emulsion in water does both. *And so
on. *One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. *There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007. *

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages. *

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry. *(http://tinyurl.com/l27kaq) *Does he use chemical explanations for the role of sulfur in helping

It's quite the tome. *Although it did scratch the itch, it was far more
than I wanted to know. *Glad I got it from the library.

Does he use chemical explanations for the role of sulfur in helping metal
cutting operations? *(sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows. *

This was a big question, for exactly that reason. *It turns out that the
effect *is* chemical. *The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. *One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has a
lot of chlorine.

I assume that research continues, if only because the perplexing and *
counter-intuitive behavior interests people, especially university
professors.

*Some reactions are fast and it
could be that surface chemistry is involved. *Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. *Sulfur and chlorine rule. *

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not, or
there would be a lot of freon-based cutting fluids.

This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright:http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have such
large coolant flows.

Joe Gwinn- Hide quoted text -

- Show quoted text -

I found an inexpensive copy on Amazon and ordered it. It might be
over my head, but I'm curious. I imagine that controlling the
"transition temperature" (ductile/brittle phases) of the material is
also involved with coolant. Probably lots of science going on at that
little tip.

On Jun 27, 5:08*pm, "Ed Huntress" wrote:
"Joseph Gwinn" wrote in message
...

When you get into really high-speed cutting, Joe, they often run dry -- or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.
--
Ed Huntress

The Cincinnatti Milling Machine book that Lindsay used to sell (and I
can't find) contained reports on extensive cutting experiments that
seem to be the origin of accepted practice. IIRC their results were
considerably less definitive than the rules that developed, for
instance they found little difference between oiled and dry on cast
iron, and suggested dry mainly to minimize the mess. I've based my
practice of using a minimum of brushed-on oil on their results,
considering that I make one-off parts and can easily regrind a drill
or lathe bit afterwards.

jsw

On 2009-06-27, Ed Huntress wrote:

[ ... ]

Where cutting forces or non-cutting friction is high, you can add sulfur to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such as
tapping, benefit from the sulfur.

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else? I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs. :-)

You can also add chlorine or a variety of
other chemicals to get a somewhat mysterious reduction in shear strength at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the '50s.
Maybe they have it figured out now. They didn't when I was writing about it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength right
at the cutting edge. Don't use it.

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"Jim Wilkins" wrote in message
...
On Jun 27, 5:08 pm, "Ed Huntress" wrote:
"Joseph Gwinn" wrote in message
...

When you get into really high-speed cutting, Joe, they often run dry -- or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.
--
Ed Huntress

The Cincinnatti Milling Machine book that Lindsay used to sell (and I
can't find) contained reports on extensive cutting experiments that
seem to be the origin of accepted practice. IIRC their results were
considerably less definitive than the rules that developed, for
instance they found little difference between oiled and dry on cast
iron, and suggested dry mainly to minimize the mess. I've based my
practice of using a minimum of brushed-on oil on their results,
considering that I make one-off parts and can easily regrind a drill
or lathe bit afterwards.

jsw

================================================== ==

Cincinnati Milling sponsored some of the university research and was a great
source of data at one time.

The real high-speed stuff, machining dry with advanced cutting tools, is
something that's developed over the past ten or fifteen years or so in real
high-volume production. It came in with the widespread use of CBN,
multi-layered coated carbide, and to a lesser extent, with diamond coatings.

Those multi-layer coatings can't stand any thermal shock, but they can
tolerate very high temperatures.

Some coatings flat out won't do their job if you run them with coolant. Any
of the multi-layer inserts that have a moly disulfide coating, or one or two
others, are made to "polish" the top of the insert from running dry with a
lot of friction. Then the soft coating disappears, and the hard layers
(titanium nitride, various carbo-nitrides, etc.) run best dry and hot.

The thick aluminum oxide coatings in those multi-layer tools are intended to
insulate, first by sublimating and imposing a thin gas layer between the
chip and the tool, and second just from their bulk insulating property. They
don't run right if you run them with coolant.

--
Ed Huntress

"DoN. Nichols" wrote in message
...
On 2009-06-27, Ed Huntress wrote:

[ ... ]

Where cutting forces or non-cutting friction is high, you can add sulfur
to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such
as
tapping, benefit from the sulfur.

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else?

Ya got me. I forget what they recommend. When I had a specialized question
like that I'd call the people who made the tools. They usually know better
than anyone.

I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs.
:-)

Hey, it's better than the way I used to tap (fairly) hard steel...with
carbon tet, holding my breath and then running up the stairs every twenty
seconds or so, to breathe. g

That was after we knew it was bad for you. Before we knew, when I was a kid,
I made whole quarts of dry-fly dope by dissolving paraffin wax in carbon
tet, in an open jar. Sheesh.


You can also add chlorine or a variety
of
other chemicals to get a somewhat mysterious reduction in shear strength
at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the
'50s.
Maybe they have it figured out now. They didn't when I was writing about
it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength
right
at the cutting edge. Don't use it.

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

It was the 1,1,1. I still have a half can of it. And yes, I've gotten the
black bubbling mess and smoke that you get when you use it on aluminum. g

Jeez, that scared me when I saw that. I thought it was going to melt through
to China.


Enjoy,
DoN.

--
Ed Huntress

On 2009-06-27, Ed Huntress wrote:
Where cutting forces or non-cutting friction is high, you can add sulfur to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such as
tapping, benefit from the sulfur. You can also add chlorine or a variety of
other chemicals to get a somewhat mysterious reduction in shear strength at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the '50s.
Maybe they have it figured out now. They didn't when I was writing about it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength right
at the cutting edge. Don't use it.

Ed, can you elaborate on your "do not use them" statement. I have old
"GALAXY thread cutting oil" with sulphur and chlorine base. It seems
to work well. Is it harmful to health?

i

"Ignoramus16724" wrote in message
...
On 2009-06-27, Ed Huntress wrote:
Where cutting forces or non-cutting friction is high, you can add sulfur
to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such
as
tapping, benefit from the sulfur. You can also add chlorine or a variety
of
other chemicals to get a somewhat mysterious reduction in shear strength
at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the
'50s.
Maybe they have it figured out now. They didn't when I was writing about
it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength
right
at the cutting edge. Don't use it.

Ed, can you elaborate on your "do not use them" statement.

I should have made clear that I was saying not to use carbon tetrachloride.
I don't want to be sued when somebody's liver and kidneys collapse. d8-)

Chlorine has been taken out of many cutting fluids, too. Sulfur is still
common in the thick formulas used for thread-cutting of pipe, and you can
still get sulfated cutting oil for turning and milling, too.

I have old
"GALAXY thread cutting oil" with sulphur and chlorine base. It seems
to work well. Is it harmful to health?

I don't know. There are cautions that you'll see particularly regarding
chlorine. How serious it is, I don't know.

But I'm hardly the one to ask. When I need a chemical for cleaning, cutting,
or whatever, I go for the one with the skull and crossbones on the label. It
usually works the best.

--
Ed Huntress

In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article
,
"Denis G." wrote:

On Jun 26, 3:14 pm, Joseph Gwinn wrote:
In article ,
Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds
me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot without
it
that the edge is dulled? I thought HSS & especially carbide could
stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips
to
cutting tool, which causes effective dulling. The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. This usually results in better surface finish, and may yield
better accuracy as well.

3. Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? Or both?

It mostly depends on the material being cut. This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. Plain water (used when machining some plastics) is a pure
coolant. Wax is a pure lubricant. Oil in flood is a lubricant with
significant cooling ability. Oil emulsion in water does both. And so
on. One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007.

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages.

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry.
(http://tinyurl.com/l27kaq) Does he use chemical explanations for the
role of sulfur in helping

It's quite the tome. Although it did scratch the itch, it was far more
than I wanted to know. Glad I got it from the library.


Does he use chemical explanations for the role of sulfur in helping metal
cutting operations? (sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows.

This was a big question, for exactly that reason. It turns out that the
effect *is* chemical. The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has a
lot of chlorine.

I assume that research continues, if only because the perplexing and
counter-intuitive behavior interests people, especially university
professors.


Some reactions are fast and it
could be that surface chemistry is involved. Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. Sulfur and chlorine rule.

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not, or
there would be a lot of freon-based cutting fluids.


This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright: http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have such
large coolant flows.

Joe Gwinn

When you get into really high-speed cutting, Joe, they often run dry -- or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.

Yeah, that's now true, at least for the 40000 rpm spindle folks.

Most of the machining centers I've seen use a flood though.


BTW, I had lunch with Milton Shaw, back in the mid-'70s. We used his work
for several technical articles at _American Machinist_, 'way back when.

So he was the guru he seems to be.

Joe Gwinn

In article ,
"DoN. Nichols" wrote:

On 2009-06-27, Ed Huntress wrote:

[ ... ]

Where cutting forces or non-cutting friction is high, you can add sulfur to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such
as
tapping, benefit from the sulfur.

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else? I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs. :-)

I think that SulFlo is flowers of sulfur dispersed in heavy oil,
probably made in a ball mill (like paint).


You can also add chlorine or a variety of
other chemicals to get a somewhat mysterious reduction in shear strength at
the cutting edge. Somehow they get right into the shear area and reduce
cutting forces. This was the subject of a lot of research during the '50s.
Maybe they have it figured out now. They didn't when I was writing about
it,
in the '70s and early '80s. The extreme example of this was carbon
tetrachloride, which produced a very large reduction in shear strength
right at the cutting edge. Don't use it.

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

The research guys still use carbon tet, mainly trying to invent
something that works that well.

Joe Gwinn

In article
,
"Denis G." wrote:

On Jun 27, 3:45*pm, Joseph Gwinn wrote:
In article
,
*"Denis G." wrote:







On Jun 26, 3:14*pm, Joseph Gwinn wrote:
In article ,
*Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe reminds
me
of questions that I have.

1. *What is the purpose of cooling? *Does the tool get so hot without
it
that the edge is dulled? *I thought HSS & especially carbide could
stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of chips
to
cutting tool, which causes effective dulling. *The second purpose is to
keep the tool itself cool, so the cutting edge won't become soft. *With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. *What is the purpose of cutting oil? *I remember reading that it
allowed chips to flow off the cutting edge more easily. *Is that it?

Reduces cutting force by lubricating the interface between tool bit and
workpiece. *This usually results in better surface finish, and may
yield
better accuracy as well.

3. *Does choice of cooling or lube depend upon the tool (lathe, mill,
drill press, band saw), or material? *Or both? *

It mostly depends on the material being cut. *This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. *Plain water (used when machining some plastics) is a pure
coolant. *Wax is a pure lubricant. *Oil in flood is a lubricant with
significant cooling ability. *Oil emulsion in water does both. *And so
on. *One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome to
be precise. *There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007. *

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages. *

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry.
*(http://tinyurl.com/l27kaq) *Does he use chemical explanations for the
role of sulfur in helping

It's quite the tome. *Although it did scratch the itch, it was far more
than I wanted to know. *Glad I got it from the library.

Does he use chemical explanations for the role of sulfur in helping metal
cutting operations? *(sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows. *

This was a big question, for exactly that reason. *It turns out that the
effect *is* chemical. *The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. *One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has a
lot of chlorine.

I assume that research continues, if only because the perplexing and *
counter-intuitive behavior interests people, especially university
professors.

*Some reactions are fast and it
could be that surface chemistry is involved. *Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. *Sulfur and chlorine rule. *

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not, or
there would be a lot of freon-based cutting fluids.

This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright:http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have such
large coolant flows.

Joe Gwinn- Hide quoted text -

- Show quoted text -

I found an inexpensive copy on Amazon and ordered it. It might be
over my head, but I'm curious.

Good find.


I imagine that controlling the
"transition temperature" (ductile/brittle phases) of the material is
also involved with coolant. Probably lots of science going on at that
little tip.

Absolutely. I wonder what the successor book is, if any.

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Joseph Gwinn" wrote in message
...
In article
,
"Denis G." wrote:

On Jun 26, 3:14 pm, Joseph Gwinn wrote:
In article ,
Bob Engelhardt wrote:

Joe's recent thread about his dribble cooling for his lathe
reminds
me
of questions that I have.

1. What is the purpose of cooling? Does the tool get so hot
without
it
that the edge is dulled? I thought HSS & especially carbide could
stand
the temperatures created by HSM work.

The first purpose of cooling is primarily to prevent welding of
chips
to
cutting tool, which causes effective dulling. The second purpose is
to
keep the tool itself cool, so the cutting edge won't become soft.
With
modern tool steels and carbides one can go far faster before this
happens, but cooling always allows one to go faster than dry.

2. What is the purpose of cutting oil? I remember reading that it
allowed chips to flow off the cutting edge more easily. Is that
it?

Reduces cutting force by lubricating the interface between tool bit
and
workpiece. This usually results in better surface finish, and may
yield
better accuracy as well.

3. Does choice of cooling or lube depend upon the tool (lathe,
mill,
drill press, band saw), or material? Or both?

It mostly depends on the material being cut. This is discussed at
length in Machinery Handbook.

Coolants have various combinations of cooling effect and lubrication
effect. Plain water (used when machining some plastics) is a pure
coolant. Wax is a pure lubricant. Oil in flood is a lubricant with
significant cooling ability. Oil emulsion in water does both. And so
on. One can make a career of this.

[snip]

There are tables in the Machinery Handbook.

If you really want to dive into the details, there is a book, a tome
to
be precise. There was a thread on this titled "Metal Cutting
Principles, the tome" posted on 14 April 2007.

The book is "Metal Cutting Principles", 2nd edition, Milton C. Shaw,
Oxford University Press, 2005, 651 pages.

I will say that parts of this book are very heavy going.

Joe Gwinn- Hide quoted text -

- Show quoted text -

Joe,

I noticed that Shaw has a doctorate in chemistry.
(http://tinyurl.com/l27kaq) Does he use chemical explanations for the
role of sulfur in helping

It's quite the tome. Although it did scratch the itch, it was far more
than I wanted to know. Glad I got it from the library.


Does he use chemical explanations for the role of sulfur in helping
metal
cutting operations? (sulfur cutting oils/high sulfur steels)
It seems unlikely that a chemical reaction would have time to
influence cutting, but who knows.

This was a big question, for exactly that reason. It turns out that
the
effect *is* chemical. The tests consisted of soaking a test piece in
carbon tetrachloride or whatever, and then machining the test piece
after waiting for various periods of time or heating the piece, et al.

The high temperature and/or severe mechanical shearing forces split the
molecules, releasing the sulfur or chlorine atoms which then combine
with the atomically clean just-created metal surfaces, preventing
welding back together.

How the molecules get to the point of use is still a bit of a mystery,
but otherwise it's well established that they do. One theory is that
the mechanical strain of cutting opens little tears and/or widens
existing pores in the metal being cut, and that the reason carbon
tetrachloride is so effective is that it penetrates very well, and has
a
lot of chlorine.

I assume that research continues, if only because the perplexing and
counter-intuitive behavior interests people, especially university
professors.


Some reactions are fast and it
could be that surface chemistry is involved. Maybe lead-based cutting
fluids would be effective (if not for environmental/health problems).

I don't recall that there were any lead-based cutting fluids, even in
research. Sulfur and chlorine rule.

Except that metallic lead in steel yields a very machinable alloy.

I don't recall if fluorine works, but I would guess that it does not,
or
there would be a lot of freon-based cutting fluids.


This book has a chapter on coolants and lubrication:
³Metal Cutting² by Edward Trent & Paul Wright:
http://tinyurl.com/p2l94p
It says that a more effective place to direct cutting fluid is along
the flank of the cutting tool or from underneath the cut.

Yes, basically flood the area, top and bottom.

Modern high-speed machining centers almost run underwater they have
such
large coolant flows.

Joe Gwinn

When you get into really high-speed cutting, Joe, they often run dry --
or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.

Yeah, that's now true, at least for the 40000 rpm spindle folks.

Most of the machining centers I've seen use a flood though.


BTW, I had lunch with Milton Shaw, back in the mid-'70s. We used his work
for several technical articles at _American Machinist_, 'way back when.

So he was the guru he seems to be.

Joe Gwinn

Oh, yeah. He was the most respected researcher in the field for decades. He
just died a few years ago.

--
Ed Huntress

On 2009-06-28, Joseph Gwinn wrote:
When you get into really high-speed cutting, Joe, they often run dry -- or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.

Yeah, that's now true, at least for the 40000 rpm spindle folks.

Most of the machining centers I've seen use a flood though.

How do they keep the cutter cool, then?

i

"Ignoramus11030" wrote in message
...
On 2009-06-28, Joseph Gwinn wrote:
When you get into really high-speed cutting, Joe, they often run dry --
or
with a 1/2-liter per 24 hour lean oil (vegetable) mist.

Yeah, that's now true, at least for the 40000 rpm spindle folks.

Most of the machining centers I've seen use a flood though.

How do they keep the cutter cool, then?

i

They don't. They're meant to run very, very hot. The ones with aluminum
oxide coatings count on the heat to sublimate the AlOx layer, which then
insulates the other layers with a film of gas.

--
Ed Huntress

On 2009-06-28, Ed Huntress wrote:

"DoN. Nichols" wrote in message
...
On 2009-06-27, Ed Huntress wrote:

[ ... ]

Where cutting forces or non-cutting friction is high, you can add sulfur
to
oil and you get more film strength, with little influence on lubrication,
without increasing the puncture threshold. Tough cutting conditions, such
as
tapping, benefit from the sulfur.

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else?

Ya got me. I forget what they recommend. When I had a specialized question
like that I'd call the people who made the tools. They usually know better
than anyone.

O.K. I've first got to figure out who made the ones which I
have. I got them from MSC a while back. :-) And -- they'll probably
want to know what I am planning to tap with them -- and that is also
variable. :-)

I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs.
:-)

Hey, it's better than the way I used to tap (fairly) hard steel...with
carbon tet, holding my breath and then running up the stairs every twenty
seconds or so, to breathe. g

Wow!

That was after we knew it was bad for you. Before we knew, when I was a kid,
I made whole quarts of dry-fly dope by dissolving paraffin wax in carbon
tet, in an open jar. Sheesh.

I was using it to clean the gates of the school's movie
projectors -- in the projection booth during study hall, so I kept the
door closed. I spent the next two days in the infirmary (a prep
school). :-)

[ ... ]

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

It was the 1,1,1. I still have a half can of it. And yes, I've gotten the
black bubbling mess and smoke that you get when you use it on aluminum. g

:-)

Jeez, that scared me when I saw that. I thought it was going to melt through
to China.

I was tapping holes in a friend's aluminum beer keg, which he
wanted to turn into a large piggy bank -- with the screws to secure a
hasp holding the plug in the hole for emptying it. :-)

I wonder whether he still has it? He has been through two more
wives, and I don't know how many moves since then.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2009-06-28, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else? I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs. :-)

I think that SulFlo is flowers of sulfur dispersed in heavy oil,
probably made in a ball mill (like paint).

That is what it looks like at least. It is quite nice for heavy
cutting.

[ ... ]

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

The research guys still use carbon tet, mainly trying to invent
something that works that well.

I wonder whether we will hear about it if they do -- or there
will simply be another "miracle ingredient" cutting fluid on the market
with no way to tell what it is? :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2009-06-28, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

What is the best fluid to use for roll (form) tapping? High
sulfur? Mollybdimum Disulfide? Something else? I've got some stuff
which appears to be mostly powdered sulfur in an oil carrier -- looks
kind of like mustard, and about as thick. IIRC, it is called
"Sul-Flo". This is nice where high cutting forces are involved, but you
want good airflow to get the smell of burning sulfur out of your lungs. :-)

I think that SulFlo is flowers of sulfur dispersed in heavy oil,
probably made in a ball mill (like paint).

That is what it looks like at least. It is quite nice for heavy
cutting.

[ ... ]

Wasn't that what was in the original Tap-Magic? Or was it
1,1,1, Trichlor? Whatever was there, it was certainly bad news when
tapping aluminum. :-)

The research guys still use carbon tet, mainly trying to invent
something that works that well.

I wonder whether we will hear about it if they do -- or there
will simply be another "miracle ingredient" cutting fluid on the market
with no way to tell what it is? :-)

The MSDS will give them away.

But more to the point, this would be a billion dollar invention. If it
is not patented, it will be stolen. In either case, it will soon become
public.

Joe Gwinn