Here is an interesting factoid: The modulus of elasticity (stiffness)
for steel is about 30 million PSI and is not effected by its hardness.
The hardest pieces of HSS will defect the same amount as the softest
paper clip, given the same shape, so long as you stay within the
elastic limits of the material. The difference between the two is the
yield point. The soft steel reaches a point and yields (takes a
permanent set) instead of offering more resistance against a force
where the hard steel will continue to deflect in a linear correlation
to applied force until it fails (at a relatively high amount of
deflection). The moral to this story is that, so long as you're not
subjecting steel to forces that cause a permanent deformation or
failure, they are all the same in stiffness, regardless of their
hardness and (mostly) their alloy composition. There is nothing you can
do to steel to make it stiffer. Period. Sorry.
Which brings me to why I use carbide in difficult length to diameter
situations. Yes, carbide does not hold up well to chatter, but HSS will
chatter worse, all else equal. If you're chattering, you're cutting too
deep, or feeding too slow, or turning too fast. If you're experiencing
chatter in a cut, and you want the cutter to survive, use HSS. If you
want you part to not be covered in chatter, use carbide and modify your
program to eliminate chatter. I'd love to get the input of someone like
BB or BD who know more about this subject than I do to get their
Which brings me to this question (and the point of this dissertation)
How does the flex mod of powdered metal compare to carbide? Is it
basically an iron alloy, limited to 30 million PSI, or is it something
Congrats to Polymer Man. You fit into my 100 to 1 theory. It is surprising
how few people know you can't change stiffness (modulus of elasticity) by
heat treat or alloy. I worked in an aircraft mechanical testing lab for five
years and must have done 50,000 tensile tests and still had no knowledge of
this principle. I recently brought it up to a very veteran tool steel
salesman, and an arguement instantly started. I have a carpenter tool steel
book that shows clearly the tests that proved my point. All I got was a
dirty look and probably lost any discounts I may have got from him!
P.S. 100 to 1 is probably being way to nice.
"It is surprising
how few people know you can't change stiffness (modulus of elasticity)
heat treat or alloy."
Thanks Dixon, glad to make your list.
Yeah, I've had similar conversations with people about the use of 4130
in a race car. Yeah, it is stronger, but it can't effect handing
(compared to plain 'ol HRPO) because it isn't any stiffer. Oh, and
parts made of 6-4 titanium may be stronger and lighter, but they'll
only be half as stiff as old fashioned FE.
I doubt the additional control over the metallurgical properties and
grain structure possible in PM tooling will change the stiffness. Those
characteristics are what you're modifying in carbon steel through
alloying and heat treatment, and it has no effect in conventional
steel, what would make PM special if it is also FE based?
Cutter flexibility causes me all kind of problems when the length gets
to be 8 or 12 times the diameter. In that situation I'll use carbide,
but not for its additional hardness or high heat performance, but for
I wish BD or BB would comment on their experiences, where they may use
carbide, but not run it up fast but because it doesn't deflect as much.
Here are some factoids somewhat related to your points: Figures are
Steel density around 7.8 (g/cc), modulus of elasticity 30,000,000 PSI
Aluminum density around 2.7 (g/cc), modulus of elasticity 10,000,000 PSI
Titanium density around 4.5 (g/cc), modulus of elasticity 15,000,000 PSI
Tungsten Carbide density around 15 (g/cc), modulus of elasticity
65,000,000 - 90,000,000 PSI
Summarized: Aluminum has about 1/3 the density of steel and has a
modulus 1/3 as great.
Titanium has about 1/2 the density of steel, and has a modulus of 1/2
that of steel
Carbide has a density about double than of steel, and has a modulus
over twice as much as steel.
But density certainly isn't the full story since the density of Lead is
around 11 (g/cc), and its modulus of elasticity is only 2,500,000 PSI.
Actually, probably everyone has used long carbide cutters mainly to
resist deflection. We were just cutting a thru pocket in a 12" cubical
block today (half-way through from either side), with a 1" dia.
finishing carbide cutter 6"-7" long and running it at about 450 RPM and
15 IPM around the inner perimeter.
I was just making an observation "that in those three cases" the
modulus of elasticity follows the density of the material. Do you doubt
that factoid? Did I ever state that the density was a necessary sole
causative factor? No, I did not. In fact I also wrote the following to
dissuade anyone of coming to that conclusion:
"But density certainly isn't the full story since the density of Lead
around 11 (g/cc), and its modulus of elasticity is only 2,500,000 PSI."
But you seem to have accidentally edited that comment of mine out of
your reply. I'm sure you wouldn't stoop to using such an obvious
trolling tactic of editing other's comments to make it appear they said
something they didn't, now would you.
BTW, since when is Diamond a metal? The subject was metals and their
Uranium is indeed very dense and it's modulus is close to steel, but
I'd venture to guess that few machinists have worked with that
particular metal. But most everyone can identify with the properties of
lead as being simultaneously dense AND soft, so I think it's a better
example for most machinists.
Umm .. It's not? HTH.
What do you think that metals are?
Carbides were mentioned and you just mentioned Tungsten Carbide
(Subcategory: Carbide; Ceramic), which has an Electrical Resistivity
of 5.3e-005 to 8e-005 ohm-cm .
I never considered it a metal. I know better.
The "LMAO" seems to be on you .
Up early? Too late? Confused?
"You don't think Tungsten Carbide is a metal? LMAO!"
But it's NOT a metal .
Properties of Tungsten Carbide
Thermal Conductivity - Tungsten carbide is in the range of twice that of
tool steel and carbon steel.
Electrical Conductivity - Tungsten carbide is in the same range as tool
steel and carbon steel.
If carbide end mills weren't electrically conductive they wouldn't make
my LED conductive tool length offsetting tool work, but they do.
Tungsten carbide cutting tools sure seem to fit the criteria for metals
If you have some evidence to the contrary (that's EVIDENCE now - not
opinion), let's hear it.
You are confused .
And you opine is that Carbides are metals.
You don't seem to know, eh?
Lint attack again?
No "perhaps" about it, BB.
I think Wick got you yet again.
What part of "CARBIDE" was unclear?
WHY? Think you'll find either Carbides or Tungsten Carbide there?
Good for you. You can copy & paste stuff.
So can jb.
NOW it's "Tungsten carbide tooling" .....
Rocks are opaque too so I suppose that you think that they are metals too ...
yet Sodium is soft ...
steel =~ Thermal Conductivity 51.9 W/m-K 360 BTU-in/hr-ft²-°F
Tungsten Carbide, WC =~ Thermal Conductivity 100 W/m-K 694 BTU-in/hr-ft²-°F
Natural Diamond =~ Thermal Conductivity 2000 W/m-K 13900 BTU-in/hr-ft²-°F
So Diamond is a metal too?
It's not my fault that you are unable to support your claim, and seem
to be in a snit over it.
Heh, let's call it a working hypothesis, which can change when
convincing contradicting evidence is presented.
You're the one that said you "knew better", yet you have presented no
factual evidence, or even a plausible explanation so far, that in any
way contradicts the premise that Tungsten Carbide is a metal.
I'm not the one that is having trouble backing up his claim.
Do you see the word "CARBIDE" in my sentence above where I said: "I
think we have established beyond a reasonable doubt that Tungsten is a
I thought I'd find some general properties of metals with which we
could compare the properties of Tungsten Carbide, and I did.
IMO, copying from credible sources trumps unsupported conjecture and
WAG's any day.
Of course it's Tungsten carbide tooling, what do you think the
discussion was about, Carbide Bucky Balls?
Do all rocks have good electrical and thermal conductivity? NO!
Do all rocks have a crystalline structure? NO!
Do all rocks have a luster when polished? NO!
And YOU were just chastising ME for copying and pasting? They have a
word for someone that criticizes others for the same things THEY do.
Is Diamond a good conductor of electricity? (Probably the most
important aspect of metals and their resultant metallic bonds) NO!
Better go look at the property of metals list again and compare it to
the properties of Tungsten Carbide. You bias seems to be interfering
with your objectivity.
So the bottom line so far is that you HAVE NOT presented any factual
evidence that Tungsten carbide is NOT a metal.
But yet Tungsten carbide seems to correlate very well with the
properties of metals listed from Encarta Encyclopedia.
Like I said before, let's see some factual EVIDENCE, not unsupported
rhetoric, opinions, speculations, WAG's, or misinformation.
I by no means want to be associated with a well known troll, however, I
think the phrase is "Mettalic", not metal. Carbon is a non-metal,
Tungston is a metal, and the resulting alloy is metallic, not a metal.
Apologies in advance if someone else pointed this out.
BottleBob's not actually that bad.
But Tungsten Carbide is not an alloy.
And geeze .... "OK what is the diferance between carbide and powdered metal ?"
That's about like asking a neocon or a fundie what truth is.
Tungsten carbide, WC or W2C, is an alloy of tungsten and carbon similar
to titanium carbide. Its extreme hardness makes it useful in the
manufacture of cutting tools, abrasives and bearings, as a cheaper
alternative to diamond.
An alloy is a combination, either in solution or compound, of two or
more elements, at least one of which is a metal, and where the resultant
material has metallic properties.
Of course not. And you know very well that the excerpt from Encarta
said no such thing. You've again creatively edited out the context to
make it "appear" that something was said which really wasn't. You even
intentionally removed the complete original excerpt to make a comparison
with the full context more difficult. Here is the complete original
alloy excerpt I posted:
From Encarta Encyclopedia.
Substance composed of two or more metals. Alloys, like pure
possess metallic luster and conduct heat and electricity well, although
not generally as well as do the pure metals of which they are formed.
Compounds that contain both a metal or metals and certain nonmetals,
particularly those containing carbon, are also called alloys. The most
important of these is steel.
An alloy may consist of an intermetallic compound, a solid
an intimate mixture of minute crystals of the constituent metallic
elements, or any combination of solutions or mixtures of the foregoing.
Please note where it says: "Compounds that contain both a metal or
metals and certain nonmetals, particularly those containing carbon, are
also called alloys." Which contradicts the implication you were trying
to make (that the article was stating that carbon was a metal), by you
posting a sentence out of context.
Do you really think such misleading tactics are considered an honest
search for the truth? If someone can't be trusted to tell the truth in
a matter so inconsequential as a definition of alloy, then how can they
be trusted to tell the truth in matters much more serious and important?
This is just a little feeback 'ol buddy, but IMO, you should rethink
your habit of engaging in this sort of self-serving
maneuvering/misrepresentation, since it's not exactly improving your