i went to harbor freight last week and ran across a rotory tool with
about 60 accrssories(point and cut off wheels, etc.) could not pass it
up as it was only $7.99 and the cut off wheels and other tips would have
cost about $1.00 each, i know they dont seem like much.. the electric
tool does not have much power. i held the tip and turned it on and the
tool would not spin, but for the price i could not pass it up and could
use all the tips on my dremel rotory tool as i was looking for some more
tips for the dremel too anyway.. how good is the diamond pointed tools
and are they any good??? i see where they also have a 50 piece diamond
tool set for sale for about $19.95, but i guess it was locked up in the
cabinet as i could not see it on the shelves so i did not get it.....
the plain old emery cut off wheels go flying over my head just about
every time i use one and i was looking for something that last a little
longer, waste too much time putting a new emery cut off wheel onto the
tool.....
thanks for a reply... oh i learned that you have to use safety glasses
when using it, had 12 pieces of a broken cut off wheel in my eye in the
old days when i was too bad to think of eye protection... i learned the
hard way....

I bought a "Clark" brand on clearance at a wood tool show... Likely
a demo (or maybe return?). Lots of torque! But after about
60 seconds, the speed starts to drop, and I suspect that if there are
ball instead of sleeve bearings, it might last a few weeks rather than a
few hours.... The accessories are NOT BALANCED, and at top speed, will
further destroy the integrity of whatever bearings are present. Best
to true any stones up at moderate speed.... / mark


jim wrote:

i went to harbor freight last week and ran across a rotory tool with
about 60 accrssories(point and cut off wheels, etc.) could not pass it
up as it was only $7.99 and the cut off wheels and other tips would have
cost about $1.00 each, i know they dont seem like much.. the electric
tool does not have much power. i held the tip and turned it on and the
tool would not spin, but for the price i could not pass it up and could
use all the tips on my dremel rotory tool as i was looking for some more
tips for the dremel too anyway.. how good is the diamond pointed tools
and are they any good??? i see where they also have a 50 piece diamond
tool set for sale for about $19.95, but i guess it was locked up in the
cabinet as i could not see it on the shelves so i did not get it.....
the plain old emery cut off wheels go flying over my head just about
every time i use one and i was looking for something that last a little
longer, waste too much time putting a new emery cut off wheel onto the
tool.....
thanks for a reply... oh i learned that you have to use safety glasses
when using it, had 12 pieces of a broken cut off wheel in my eye in the
old days when i was too bad to think of eye protection... i learned the
hard way....

I bought several packages of their diamond cutoff wheels, they last a while
as long as they are not overheated. Bought two or three blister cards of 5
over a year ago when they were on sale, I am only on my second disc (light
use only or where I need
the thinnest kerf possible, otherwise I use a bigger tool). I killed the
edge of
first disc working too hard at cutting a hardened parting tool. For the
price, I am impressed.

I have my doubts about the other ones, several of the diamond sets I have
inspected had visibly eccentric tips or were worm shaped.

StaticsJason

"jim" wrote in message ...
i went to harbor freight last week and ran across a rotory tool with
about 60 accrssories(point and cut off wheels, etc.) could not pass it
up as it was only $7.99 and the cut off wheels and other tips would have
cost about $1.00 each, i know they dont seem like much.. the electric
tool does not have much power. i held the tip and turned it on and the
tool would not spin, but for the price i could not pass it up and could
use all the tips on my dremel rotory tool as i was looking for some more
tips for the dremel too anyway.. how good is the diamond pointed tools
and are they any good??? i see where they also have a 50 piece diamond
tool set for sale for about $19.95, but i guess it was locked up in the
cabinet as i could not see it on the shelves so i did not get it.....
the plain old emery cut off wheels go flying over my head just about
every time i use one and i was looking for something that last a little
longer, waste too much time putting a new emery cut off wheel onto the
tool.....
thanks for a reply... oh i learned that you have to use safety glasses
when using it, had 12 pieces of a broken cut off wheel in my eye in the
old days when i was too bad to think of eye protection... i learned the
hard way....

"Statics" wrote in message
news:5Fzub.461$b64.76@okepread02...
I bought several packages of their diamond cutoff wheels, they last a
while
as long as they are not overheated. Bought two or three blister cards of
5
over a year ago when they were on sale, I am only on my second disc (light
use only or where I need
the thinnest kerf possible, otherwise I use a bigger tool). I killed the
edge of
first disc working too hard at cutting a hardened parting tool. For the
price, I am impressed.

I have my doubts about the other ones, several of the diamond sets I have
inspected had visibly eccentric tips or were worm shaped.

StaticsJason

Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much any
kind. Reason? Diamonds are, of course, carbon, and iron has an affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve into
the steel you're trying to cut. That dulls the diamonds rapidly, leading
to higher temperatures, and, of course, faster dissolution of the diamond.

Harold

On Tue, 18 Nov 2003 20:19:16 -0800, "Harold & Susan Vordos"
wrote:



Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much any
kind. Reason? Diamonds are, of course, carbon, and iron has an affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve into
the steel you're trying to cut. That dulls the diamonds rapidly, leading
to higher temperatures, and, of course, faster dissolution of the diamond.


Actually, diamond tools work quite well against steel if run slowly! quite
handy for honing tools with.

Regards
Mark Rand
RTFM

Harold & Susan Vordos wrote:

"Statics" wrote in message
news:5Fzub.461$b64.76@okepread02...
I bought several packages of their diamond cutoff wheels, they last a
while
as long as they are not overheated. Bought two or three blister cards of
5
over a year ago when they were on sale, I am only on my second disc (light
use only or where I need
the thinnest kerf possible, otherwise I use a bigger tool). I killed the
edge of
first disc working too hard at cutting a hardened parting tool. For the
price, I am impressed.

I have my doubts about the other ones, several of the diamond sets I have
inspected had visibly eccentric tips or were worm shaped.

StaticsJason

Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much any
kind. Reason? Diamonds are, of course, carbon, and iron has an affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve into
the steel you're trying to cut. That dulls the diamonds rapidly, leading
to higher temperatures, and, of course, faster dissolution of the diamond.

Harold

Most of what you said as an explanation is not true. I have
no idea what a dissolute diamond is but many dissolute
people seem to be attracted to diamonds.

My limited experience with diamond tools is that the cheap ones are nearly
worthless. The problem is that the diamonds are bonded in a single layer to
a core. If this bond is easily broken, you soon have a "dissolute" core,
without enough diamonds to do much cutting.

"George E. Cawthon" wrote in message
...


Harold & Susan Vordos wrote:

"Statics" wrote in message
news:5Fzub.461$b64.76@okepread02...
I bought several packages of their diamond cutoff wheels, they last a
while
as long as they are not overheated. Bought two or three blister cards
of
5
over a year ago when they were on sale, I am only on my second disc
(light
use only or where I need
the thinnest kerf possible, otherwise I use a bigger tool). I killed
the
edge of
first disc working too hard at cutting a hardened parting tool. For
the
price, I am impressed.

I have my doubts about the other ones, several of the diamond sets I
have
inspected had visibly eccentric tips or were worm shaped.

StaticsJason

Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much
any
kind. Reason? Diamonds are, of course, carbon, and iron has an
affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve
into
the steel you're trying to cut. That dulls the diamonds rapidly,
leading
to higher temperatures, and, of course, faster dissolution of the
diamond.

Harold

Most of what you said as an explanation is not true.

Perhpas you can tell all of us what is true, then!

I have
no idea what a dissolute diamond is but many dissolute
people seem to be attracted to diamonds.

With that, I would likely agree.

Likely I have egg on my face regards a word chosen to describe a diamond
being dissolved into steel (my mom told me I should have gone to college),
but the principle is one well known by anyone that works with diamond
grinding wheels. The information is well documented by the grinding
industry. Diamonds are not recommended for use in grinding steels, and for
the exact reason mentioned. The dulling of the diamonds lead to other
problems as well, they are not limited to just further dulling. Pulling
the dull diamond from the bonding matrix is one more of the problems.
Diamond wheels experience very short life spans when used improperly.

It's the same with silicon carbide grinding wheels on steel, which, like
diamond, dissolves into the steel being ground. If you've ever run any
kind or grinder and had poor results, you'll now understand why an aluminum
oxide wheel, in spite of being a lot softer (the abrasive, not the bond)
than a silicon carbide wheel, cuts steel exceedingly well, while the silicon
wheel dulls up instantly and creates lots of heat but does little grinding.
That characteristic is very obvious on a surface grinder, where the wheel
behaves as if it's loaded shortly after being dressed.

Did I use a selection of words that please you this time? If not, learn
something from the message, and replace the improper words with those of
your choosing.

Harold

On Thu, 20 Nov 2003 00:27:52 +0000, Mark Rand
wrote:

On Tue, 18 Nov 2003 20:19:16 -0800, "Harold & Susan Vordos"
wrote:



Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much any
kind. Reason? Diamonds are, of course, carbon, and iron has an affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve into
the steel you're trying to cut. That dulls the diamonds rapidly, leading
to higher temperatures, and, of course, faster dissolution of the diamond.


Actually, diamond tools work quite well against steel if run slowly! quite
handy for honing tools with.

I've been wondering about this; I guess,as long as I don't eat too
many wheaties, I should be OK
Gerry :-)}
London, Canada

Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...


Harold & Susan Vordos wrote:

"Statics" wrote in message
news:5Fzub.461$b64.76@okepread02...
I bought several packages of their diamond cutoff wheels, they last a
while
as long as they are not overheated. Bought two or three blister cards
of
5
over a year ago when they were on sale, I am only on my second disc
(light
use only or where I need
the thinnest kerf possible, otherwise I use a bigger tool). I killed
the
edge of
first disc working too hard at cutting a hardened parting tool. For
the
price, I am impressed.

I have my doubts about the other ones, several of the diamond sets I
have
inspected had visibly eccentric tips or were worm shaped.

StaticsJason

Diamond tools run at elevated speeds should not be used on anything
containing iron. You'll find that these tools will hold up quite well
cutting things like rock, but not well at all on steel of pretty much
any
kind. Reason? Diamonds are, of course, carbon, and iron has an
affinity
for carbon, so at elevated temperatures the diamonds tend to dissolve
into
the steel you're trying to cut. That dulls the diamonds rapidly,
leading
to higher temperatures, and, of course, faster dissolution of the
diamond.

Harold

Most of what you said as an explanation is not true.

Perhpas you can tell all of us what is true, then!

I have
no idea what a dissolute diamond is but many dissolute
people seem to be attracted to diamonds.

With that, I would likely agree.

Likely I have egg on my face regards a word chosen to describe a diamond
being dissolved into steel (my mom told me I should have gone to college),
but the principle is one well known by anyone that works with diamond
grinding wheels. The information is well documented by the grinding
industry. Diamonds are not recommended for use in grinding steels, and for
the exact reason mentioned. The dulling of the diamonds lead to other
problems as well, they are not limited to just further dulling. Pulling
the dull diamond from the bonding matrix is one more of the problems.
Diamond wheels experience very short life spans when used improperly.

It's the same with silicon carbide grinding wheels on steel, which, like
diamond, dissolves into the steel being ground. If you've ever run any
kind or grinder and had poor results, you'll now understand why an aluminum
oxide wheel, in spite of being a lot softer (the abrasive, not the bond)
than a silicon carbide wheel, cuts steel exceedingly well, while the silicon
wheel dulls up instantly and creates lots of heat but does little grinding.
That characteristic is very obvious on a surface grinder, where the wheel
behaves as if it's loaded shortly after being dressed.

Did I use a selection of words that please you this time? If not, learn
something from the message, and replace the improper words with those of
your choosing.

Harold

Not my job to tell you what is true, but diamonds don't
dissolve and they certainly don't dissolve into steel. The
diamonds in a wheel can shatter (break), they can be pulled
out of the wheel matrix, and they can be smeared with either
the wheel matrix or the material being ground. The latter
is what happens when you say it loads up. Loading depends
on a lot of things but highly important are the coarseness
of the abrasive, the bond of the abrasive, and the speed of
the wheel.

If silicon carbide is so bad on steel, how come most small
bench grinders come with silicon carbide wheels? Granted
that not every abrasive is suitable for every material.
However, you can cut and polish just about everything with
the correct grades of diamond. As another person stated,
diamonds work quite well on steel.

Diamonds don't work well at the high speeds used in many
industrial tools and they certainly won't last long without
a cooling/lubricating fluid. However, speed is often much
more important that cost, but that's no reason to not
understand the physical process. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

"George E. Cawthon" wrote in message
...
.. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold

You need to look at some very basic chemisty behind the
diamond. Diamonds are the hardest material known for some
very basic reasons. It's foundation is based on how
the material is put together and what holds it together.
Carbon atoms in a diamond are held together with covalent
bonds. This would make them very difficult if not next
to impossible to simply dissolve into another material,
even at temperatures experienced in grinding. See web
site listed for a quick and simplistic overview of the
two basic forces that hold atoms together.

http://people.deas.harvard.edu/~jone...lent_bond.html

There are plendy of applications where diamond wheels are
indeed used to remove steel. I have a drill doctor that
uses a diamon wheel to sharpen drills made of HSS to Carbide.
Tool grinders used diamond wheels to sharpen carbide tools.
I have some DMT and cheap HF diamond whetstones that seem to
continue to cut steel knife blades. These aren't tools that
hog material but they do cut very hard steels and contiue
to do so. Due to their fine abrasive nature, attempt to
cut soft material can easily lead to loading or
contamination issues. This will hinder the ability of the
cutting portion of the wheel to actually contact and remove
material from the work intended.

On a side note. Materials that are known to conduct
electricity better, are also known to conduct heat better.
There is on exception. An exremely good electrical
insulator is diamond. This again has to do with
covalent bonds and no free or shared electrons able to flow
about. Strangely enough diamonds are exceptional thermal
conductors.


"Harold & Susan Vordos" wrote in message ...
"George E. Cawthon" wrote in message
...
. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold

Hey this is REC. It isn't your job to post here. It is just done for
fun and helping people.

That said, I disagree with both of you. I do agree with Halold on
Diamonds. That is why Borazon is used on Steel. Diamonds don't last
and it does have to do with the fact they are carbon and I think it is
because the steel reacts with the carbon.

But I disagree with what was said about silicon Carbide. Silicon
Carbide is harder than aluminum oxide, but is not as strong. So it
works great on lower strength materials as cast iron and very hard
material as carbide. But it does not work well on steel. Does it gum
up the wheels or just wear more rapidly. I am not sure. And most
small bench grinders come with Aluminum oxide wheels. At least I have
never seen a small bench grinder for sale with Silicon Carbide wheels.
Angle grinders come with Aluminum Oxide wheels, but you can get
Silicon Carbide wheels. They are labled as Masonry wheels.

Dan


"George E. Cawthon" wrote in message

Not my job to tell you what is true, but diamonds don't
dissolve and they certainly don't dissolve into steel. The
diamonds in a wheel can shatter (break), they can be pulled
out of the wheel matrix, and they can be smeared with either
the wheel matrix or the material being ground. The latter
is what happens when you say it loads up. Loading depends
on a lot of things but highly important are the coarseness
of the abrasive, the bond of the abrasive, and the speed of
the wheel.

If silicon carbide is so bad on steel, how come most small
bench grinders come with silicon carbide wheels? Granted
that not every abrasive is suitable for every material.
However, you can cut and polish just about everything with
the correct grades of diamond. As another person stated,
diamonds work quite well on steel.

Diamonds don't work well at the high speeds used in many
industrial tools and they certainly won't last long without
a cooling/lubricating fluid. However, speed is often much
more important that cost, but that's no reason to not
understand the physical process. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold

Diatribe? now you are getting nasty. I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry. Any first year (well, maybe 2nd year)
chemistry student should be able to tell you that diamond
won't dissolve in steel. Maybe you and Norton (if they said
that) don't know what the word "dissolve" means?

You might try reading some lapidary sources, to get a more
accurate idea of cutting and polishing with diamonds. But
enough of this, as I said I'm not getting paid to educate
you. My comment was just meant as a caution to the spead of
misinformation. I've accomplished that, so I need say no
more.

On Fri, 21 Nov 2003 23:34:17 +0000, George E. Cawthon wrote:



Diatribe? now you are getting nasty. I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry.

http://www.sp3inc.com/FAQ.htm

"Why can't you machine ferrous metals with diamond?

Diamond is unaffected by almost every other chemical or compound in
nature. One exception is hot iron. The carbon atoms in diamond will
dissolve into the iron, quickly eroding the diamond surface.
Iron wheels are used for polishing natural diamond."

http://www.egr.msu.edu/~pkwon/me477/solution4.pdf

"Why is the hardest material, diamond, not good for machining ferrous
metals at high cutting speed? Diamond readily dissolves into ferrous
metals at high temperatures."

There are tons of other references online.

Hell, it should be obvious to anyone that carbon dissolves just fine
in hot iron. That's basically what steel is, after all!

"George E. Cawthon" wrote in message
...
big snip-------

If silicon carbide is so bad on steel, how come most small
bench grinders come with silicon carbide wheels?

What reason do you have to believe they do? In almost all instances
(tungsten carbide sharpening grinders excepted, those come with green wheels
or diamond), they do NOT!
Do you have any idea what constitutes a silicon carbide wheel? Can you
identify one at a glance?

Harold

Ah, you caught me on the small bench grinders. I was
thinking of lapidary equipment. Yes, two 6"x1" silicon
carbide wheels will cost more than many 6" bench grinders.
Silicon carbide is much more expensive that aluminum oxide
and diamond wheels are way more expensive. You think
economics has something do to with it? Won't comment on the
rest.

Dan Caster wrote:

Hey this is REC. It isn't your job to post here. It is just done for
fun and helping people.

That said, I disagree with both of you. I do agree with Halold on
Diamonds. That is why Borazon is used on Steel. Diamonds don't last
and it does have to do with the fact they are carbon and I think it is
because the steel reacts with the carbon.

But I disagree with what was said about silicon Carbide. Silicon
Carbide is harder than aluminum oxide, but is not as strong. So it
works great on lower strength materials as cast iron and very hard
material as carbide. But it does not work well on steel. Does it gum
up the wheels or just wear more rapidly. I am not sure. And most
small bench grinders come with Aluminum oxide wheels. At least I have
never seen a small bench grinder for sale with Silicon Carbide wheels.
Angle grinders come with Aluminum Oxide wheels, but you can get
Silicon Carbide wheels. They are labled as Masonry wheels.

Dan

"George E. Cawthon" wrote in message

Not my job to tell you what is true, but diamonds don't
dissolve and they certainly don't dissolve into steel. The
diamonds in a wheel can shatter (break), they can be pulled
out of the wheel matrix, and they can be smeared with either
the wheel matrix or the material being ground. The latter
is what happens when you say it loads up. Loading depends
on a lot of things but highly important are the coarseness
of the abrasive, the bond of the abrasive, and the speed of
the wheel.

If silicon carbide is so bad on steel, how come most small
bench grinders come with silicon carbide wheels? Granted
that not every abrasive is suitable for every material.
However, you can cut and polish just about everything with
the correct grades of diamond. As another person stated,
diamonds work quite well on steel.

Diamonds don't work well at the high speeds used in many
industrial tools and they certainly won't last long without
a cooling/lubricating fluid. However, speed is often much
more important that cost, but that's no reason to not
understand the physical process. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

"George E. Cawthon" wrote in message
...

Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their
literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold


Diatribe? now you are getting nasty.

No, I'm not getting nasty, I'm simply stating that you come across as if you
know something when you don't. Had you provided something of substance to
substantiate your claim, perhaps I would have had a different response to
your post. The information I provided is well known by any of us that
have worked in the grinding trade, especially the one about silicon carbide
dissolving it steel. That is well documented by the grinding industry, as
is the fact that aluminum oxide does the same thing when grinding glass
products. That's why rock people use silicon carbide grinding wheels
(when not using diamond), which are far better suited to the application.

I have in my possession published documentation to back my claims, and it
appears "Niccolo Vecchio" has provided enough information on the diamond
discussion to remove doubts from your mind.

Harold


I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry. Any first year (well, maybe 2nd year)
chemistry student should be able to tell you that diamond
won't dissolve in steel. Maybe you and Norton (if they said
that) don't know what the word "dissolve" means?

You might try reading some lapidary sources, to get a more
accurate idea of cutting and polishing with diamonds. But
enough of this, as I said I'm not getting paid to educate
you. My comment was just meant as a caution to the spead of
misinformation. I've accomplished that, so I need say no
more.

Niccolo Vecchio wrote:

On Fri, 21 Nov 2003 23:34:17 +0000, George E. Cawthon wrote:



Diatribe? now you are getting nasty. I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry.

http://www.sp3inc.com/FAQ.htm

"Why can't you machine ferrous metals with diamond?

Diamond is unaffected by almost every other chemical or compound in
nature. One exception is hot iron. The carbon atoms in diamond will
dissolve into the iron, quickly eroding the diamond surface.
Iron wheels are used for polishing natural diamond."

http://www.egr.msu.edu/~pkwon/me477/solution4.pdf

"Why is the hardest material, diamond, not good for machining ferrous
metals at high cutting speed? Diamond readily dissolves into ferrous
metals at high temperatures."

There are tons of other references online.

Hell, it should be obvious to anyone that carbon dissolves just fine
in hot iron. That's basically what steel is, after all!

Neither of those sites provide anything more than a
statement. I could probably find several site where Elvis
was just sighted. Besides we already know that steel can be
tooled and is tooled with diamonds. And, just as aside, you
might want to check a lapidary equipment catalog to see what
is used to facet gems including diamonds.

In article , George E. Cawthon says...

was just sighted. Besides we already know that steel can be
tooled and is tooled with diamonds.

"We" know no such thing. In fact valenite specifically
recommends against using their PCD inserts on ferrous
materials.

You can still back out of this gracefully.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

"Dan Caster" wrote in message
m...
Hey this is REC. It isn't your job to post here. It is just done for
fun and helping people.

That said, I disagree with both of you. I do agree with Halold on
Diamonds. That is why Borazon is used on Steel. Diamonds don't last
and it does have to do with the fact they are carbon and I think it is
because the steel reacts with the carbon.

Pretty much supported by the concepts in industry, although I have little to
document that concept. I do have ample information suggesting diamond
grinding wheels not be used on steel.


But I disagree with what was said about silicon Carbide.

Ah! Now we're talking. I have in my possession enough published
information to substantiate the fact that silicon carbide does, indeed,
dissolve in steel.

One must consider that at the point of contact, terrific heat is generated,
so the rules sort of change. Because of the intense heat, there is dulling
of the grain attributed to dissolving into steel. I'll gladly forward a
scan of the information to you. One of my references is a soft bound
booklet by Norton Company, copyright 1951. It is titled Lectures on
Grinding. On page 19 there are two paragraphs that describe the accepted
theory of the reaction.

Anyone interested in a scan is invited to request it. I'll get it out as
quickly as possible.

Harold

I'm amazed at how closed-minded some people are in the face of
such staggering amounts of experience and accumulated knowledge.
As far as I'm concerned, Harold, you have totally proven your case
and don't need to respond to this thread any more! - GWE

Harold & Susan Vordos wrote:

"Dan Caster" wrote in message
m...

Hey this is REC. It isn't your job to post here. It is just done for
fun and helping people.

That said, I disagree with both of you. I do agree with Halold on
Diamonds. That is why Borazon is used on Steel. Diamonds don't last
and it does have to do with the fact they are carbon and I think it is
because the steel reacts with the carbon.


Pretty much supported by the concepts in industry, although I have little to
document that concept. I do have ample information suggesting diamond
grinding wheels not be used on steel.


But I disagree with what was said about silicon Carbide.


Ah! Now we're talking. I have in my possession enough published
information to substantiate the fact that silicon carbide does, indeed,
dissolve in steel.

One must consider that at the point of contact, terrific heat is generated,
so the rules sort of change. Because of the intense heat, there is dulling
of the grain attributed to dissolving into steel. I'll gladly forward a
scan of the information to you. One of my references is a soft bound
booklet by Norton Company, copyright 1951. It is titled Lectures on
Grinding. On page 19 there are two paragraphs that describe the accepted
theory of the reaction.

Anyone interested in a scan is invited to request it. I'll get it out as
quickly as possible.

Harold

"Grant Erwin" wrote in message
...
I'm amazed at how closed-minded some people are in the face of
such staggering amounts of experience and accumulated knowledge.
As far as I'm concerned, Harold, you have totally proven your case
and don't need to respond to this thread any more! - GWE


Thanks, Grant.

I feel compelled to dispel misleading information, particularly in this
instance. The problems from wrong wheel selection are overwhelming,
speaking from experience. To get a better understanding of the
significance of the wrong wheel, try grinding some steel on your surface
grinder using a silicon carbide wheel. The net effect, and almost
instantly, is for the wheel to glaze over. Hardness of the bond makes no
difference, regardless of how you approach the problem, it persists.
Change to an aluminum oxide wheel and it "magically" goes away. The
research accomplished by Norton was right on the money.

Harold

"George E. Cawthon" wrote in message ...
Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold

Diatribe? now you are getting nasty. I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry. Any first year (well, maybe 2nd year)

Got me curious. Where's a first-year student when you need one? It
wasn't hard to find references.

U.K. chemistry professor's article, "In any application where friction
is important the diamond-coated tool bit will heat up and, in the case
of ferrous materials (be it the tool substrate or the workpiece) the
diamond coating will ultimately react with the iron and dissolve"

http://www.chm.bris.ac.uk/pt/diamond/end.htm

SP3, manufacturer of PCD tooling, "Diamond is unaffected by almost
every other chemical or compound in nature. One exception is hot iron.
The carbon atoms in diamond will dissolve into the iron, quickly
eroding the diamond surface."

http://www.sp3inc.com/FAQ.htm

Materials science encyclopedia entry for diamond, "Diamond will react
with strong carbide forming metals (i.e. tungsten, tantalum and
zirconium). It dissolves in iron, cobalt, manganese, nickel, chromium
and the platinum-group metals."

http://www.azom.com/details.asp?ArticleID=262

I have cut sapphire and other exotic stone with diamond laps.
I never cut metal.

I have hand laps that are diamond - they are used in or with water
and the action is slow. The diamond is either 'used', chips into tiny
chunks or otherwise vaporizes in spite of the water.

Localized points of contact become very hot. Blue white hot. The
diamond
might burn up or change state and then get absorbed.

I have heard of localized hardening.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

On 21 Nov 2003 18:22:18 -0800, jim rozen
wrote:

In article , George E. Cawthon says...

was just sighted. Besides we already know that steel can be
tooled and is tooled with diamonds.

"We" know no such thing. In fact valenite specifically
recommends against using their PCD inserts on ferrous
materials.

You can still back out of this gracefully.

Jim

============================
Ummm....no, I don't believe he can.

Joe
--
Heather & Joe Way
Sierra Specialty Automotive
Brake cylinders sleeved with brass
Gus Wilson Stories
http://www.brakecylinder.com

On Fri, 21 Nov 2003 18:54:04 -0800, "Harold & Susan Vordos"
wrote:


"Grant Erwin" wrote in message
...
I'm amazed at how closed-minded some people are in the face of
such staggering amounts of experience and accumulated knowledge.
As far as I'm concerned, Harold, you have totally proven your case
and don't need to respond to this thread any more! - GWE


Thanks, Grant.

I feel compelled to dispel misleading information, particularly in this
instance. The problems from wrong wheel selection are overwhelming,
speaking from experience. To get a better understanding of the
significance of the wrong wheel, try grinding some steel on your surface
grinder using a silicon carbide wheel. The net effect, and almost
instantly, is for the wheel to glaze over. Hardness of the bond makes no
difference, regardless of how you approach the problem, it persists.
Change to an aluminum oxide wheel and it "magically" goes away. The
research accomplished by Norton was right on the money.

Harold

So I take it Im not supposed to use the red wheels when grinding
aluminum or nylon?

Gunner

"The British attitude is to treat society like a game preserve where a
certain percentage of the 'antelope' are expected to be eaten by the
"lions".
Christopher Morton

"Gunner" wrote in message
...
On Fri, 21 Nov 2003 18:54:04 -0800, "Harold & Susan Vordos"
wrote:


"Grant Erwin" wrote in message
...
I'm amazed at how closed-minded some people are in the face of
such staggering amounts of experience and accumulated knowledge.
As far as I'm concerned, Harold, you have totally proven your case
and don't need to respond to this thread any more! - GWE


Thanks, Grant.

I feel compelled to dispel misleading information, particularly in this
instance. The problems from wrong wheel selection are overwhelming,
speaking from experience. To get a better understanding of the
significance of the wrong wheel, try grinding some steel on your surface
grinder using a silicon carbide wheel. The net effect, and almost
instantly, is for the wheel to glaze over. Hardness of the bond makes
no
difference, regardless of how you approach the problem, it persists.
Change to an aluminum oxide wheel and it "magically" goes away. The
research accomplished by Norton was right on the money.

Harold

So I take it Im not supposed to use the red wheels when grinding
aluminum or nylon?

Gunner

The red wheels, if they are the ruby red, are aluminum oxide, just as the
old salmon colored wheels are. The choice in both instances would be
silicon carbide, although I'm not sure that grinding nylon is done well with
either of them.

I hope you're removing the leg before grinding the nylon, Gunner! g

Harold

On Fri, 21 Nov 2003 23:06:18 -0800, "Harold & Susan Vordos"
wrote:


"Gunner" wrote in message
.. .
On Fri, 21 Nov 2003 18:54:04 -0800, "Harold & Susan Vordos"
wrote:


"Grant Erwin" wrote in message
...
I'm amazed at how closed-minded some people are in the face of
such staggering amounts of experience and accumulated knowledge.
As far as I'm concerned, Harold, you have totally proven your case
and don't need to respond to this thread any more! - GWE


Thanks, Grant.

I feel compelled to dispel misleading information, particularly in this
instance. The problems from wrong wheel selection are overwhelming,
speaking from experience. To get a better understanding of the
significance of the wrong wheel, try grinding some steel on your surface
grinder using a silicon carbide wheel. The net effect, and almost
instantly, is for the wheel to glaze over. Hardness of the bond makes
no
difference, regardless of how you approach the problem, it persists.
Change to an aluminum oxide wheel and it "magically" goes away. The
research accomplished by Norton was right on the money.

Harold

So I take it Im not supposed to use the red wheels when grinding
aluminum or nylon?

Gunner

The red wheels, if they are the ruby red, are aluminum oxide, just as the
old salmon colored wheels are. The choice in both instances would be
silicon carbide, although I'm not sure that grinding nylon is done well with
either of them.

I hope you're removing the leg before grinding the nylon, Gunner! g

Harold

I thought pulling yours would be more fun G

Gunner

"The British attitude is to treat society like a game preserve where a
certain percentage of the 'antelope' are expected to be eaten by the
"lions".
Christopher Morton

George wrote:

... " how come most small bench grinders come with silicon carbide
wheels?" ...

Most small bench grinders (if they are sold with wheels) have Aluminum
Oxide grinding wheels.

This is the most common abrasive for general steel grinding.

Leo (pearland, tx)

George E. Cawthon wrote...
I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry. Any first year (well, maybe 2nd year)
chemistry student should be able to tell you that diamond
won't dissolve in steel. Maybe you and Norton (if they said
that) don't know what the word "dissolve" means?

You might try reading some lapidary sources, to get a more
accurate idea of cutting and polishing with diamonds. But
enough of this, as I said I'm not getting paid to educate
you. My comment was just meant as a caution to the spead of
misinformation. I've accomplished that, so I need say no
more.

1. Norton is one of largest manufacturers and suppliers of abrasive
products in the world. They may even be the largest; they claim so. I
think it is safe to assume their engineers have completed at least two
years of chemistry and physics and have come to a good understanding of
the word "dissolve," but if you doubt it, you can call them and ask about
their credentials. You can reach them at one of the numbers listed on
this page:

http://www.nortonabrasives.com/locations.asp

2. You might try reading some technical literature on the use of diamonds
in cutting iron and iron alloys, including steel.

3. Your comment accomplished the opposite of your stated intent: it
spread misinformation.

Here are some more references for you to debunk, if you have time:

http://www.azom.com/details.asp?ArticleID=262
http://www.cerncourier.com/main/article/41/6/9
http://www.nature.com/nsu/020722/020722-1.html

Oh, heck, just do what I did:

http://www.google.com/search?q=diamond+dissolves+iron

Jim

Ok, Harold, you're right and I'm wrong. Hot iron dissolves
diamond. It doesn't say that in any of my chemistry books
and it doesn't say that in a chemical engineering book, it
doesn't say that in my CRC handbook, although it says
graphite is soluble in liquid iron. It says diamond melts
above 3550 degrees C, but a reference on the net indicates
that diamond breaks down at a much lower temperature. So
maybe it breaks down to graphite and then dissolves into the
steel.

In any case, there appear to be plenty of references in the
tooling industry that iron and diamond don't work together.

As I already admitted in another reply, I was wrong about
the silicon carbide wheels on small grinders. To answer
your question, nope, I can't tell the composition of a wheel
at a glance. The dry ones mostly look gray and the water or
oil soaked ones just look dark. Although silicon carbide
ones come in black and green, mine are black, just like
silicon carbide wet/dry paper. I don't have a clue what the
red wheels are as they aren't marked. I have sharpening
stones, but of the two that retain their packaging, one says
carborundum and the other says silicon carbide (unopened).
Both are the same (of course) and are essentially the same
color as my aluminum oxide grinding wheels. My packaged
grits are silicon carbide and they also have the same dark
grey color.

Well, it's been an interesting thread, and I learned
something.

Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
big snip-------

If silicon carbide is so bad on steel, how come most small
bench grinders come with silicon carbide wheels?

What reason do you have to believe they do? In almost all instances
(tungsten carbide sharpening grinders excepted, those come with green wheels
or diamond), they do NOT!
Do you have any idea what constitutes a silicon carbide wheel? Can you
identify one at a glance?

Harold

"George E. Cawthon" wrote in message
...
Ok, Harold, you're right and I'm wrong. Hot iron dissolves
diamond. It doesn't say that in any of my chemistry books
and it doesn't say that in a chemical engineering book, it
doesn't say that in my CRC handbook, although it says
graphite is soluble in liquid iron. It says diamond melts
above 3550 degrees C, but a reference on the net indicates
that diamond breaks down at a much lower temperature. So
maybe it breaks down to graphite and then dissolves into the
steel.

Actually, I think that diamonds only sublime. I'm not convinced there's a
liquid phase of carbon, but I'm no chemist. This statement should open up
another round, yes?

In any case, there appear to be plenty of references in the
tooling industry that iron and diamond don't work together.

Yep. It's been long known that they don't.

As I already admitted in another reply, I was wrong about
the silicon carbide wheels on small grinders. To answer
your question, nope, I can't tell the composition of a wheel
at a glance. The dry ones mostly look gray and the water or
oil soaked ones just look dark. Although silicon carbide
ones come in black and green, mine are black, just like
silicon carbide wet/dry paper.

That, as far as I know, is how you identify silicon carbide wheels, aside
from reading the label.. In grinding wheels, I've never seen them in any
colors except for green and black. I've long wondered why, because you
can buy silicon carbide lapping compound in gray, as you've suggested.
I'll eventually check my reference books from Norton to see if they address
that issue.


I don't have a clue what the
red wheels are as they aren't marked.

They are usually aluminum oxide. Could be wrong, though.

I have sharpening
stones, but of the two that retain their packaging, one says
carborundum and the other says silicon carbide (unopened).
Both are the same (of course) and are essentially the same
color as my aluminum oxide grinding wheels. My packaged
grits are silicon carbide and they also have the same dark
grey color.

Well, it's been an interesting thread, and I learned
something.

That's the whole idea here. Share what we know. I commend you for your
polite post acknowledging all our comments.

Harold

On Fri, 21 Nov 2003 23:34:17 GMT, "George E. Cawthon" wrote:
Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
. Let me say one last time,
there is no dissolving of diamonds or silicon carbide in the
grinding process.

Maybe you can sell your diatribe to Norton, then, because their literature
seems to think there is. But then, what the hell would the leading
manufacturer of grinding wheels know about that?

Harold

Diatribe? now you are getting nasty. I don't have a clue
who or what Norton is or says, but if they say diamond
dissolves in iron or steel, then they don't know squat about
physics or chemistry. Any first year (well, maybe 2nd year)
chemistry student should be able to tell you that diamond
won't dissolve in steel. Maybe you and Norton (if they said
that) don't know what the word "dissolve" means?

If a first or second year chemistry student told you that, it just
emphasizes the old adage that a little knowledge is a dangerous
thing. In fact carbon does dissolve in molten iron, forming a matrix
of iron carbides. This is well known to metallurgists and chemists
with more than a first year knowledge of the chemistries of iron
and carbon. Certainly the engineers at Norton, the world's largest
manufacturer of abrasives, know this.

Gary

(gradstdnt) wrote

You need to look at some very basic chemisty behind the diamond.

BZZZT!

"Leo Lichtman" wrote

My limited experience with diamond tools is that the cheap ones are
nearly worthless. The problem is that the diamonds are bonded in a
single layer to a core. If this bond is easily broken, you soon have
a "dissolute" core, without enough diamonds to do much cutting.

I like that one as IMO the most plausable counter argument.

Harold & Susan Vordos wrote:

"George E. Cawthon" wrote in message
...
Ok, Harold, you're right and I'm wrong. Hot iron dissolves
diamond. It doesn't say that in any of my chemistry books
and it doesn't say that in a chemical engineering book, it
doesn't say that in my CRC handbook, although it says
graphite is soluble in liquid iron. It says diamond melts
above 3550 degrees C, but a reference on the net indicates
that diamond breaks down at a much lower temperature. So
maybe it breaks down to graphite and then dissolves into the
steel.

Actually, I think that diamonds only sublime. I'm not convinced there's a
liquid phase of carbon, but I'm no chemist. This statement should open up
another round, yes?

In any case, there appear to be plenty of references in the
tooling industry that iron and diamond don't work together.

Yep. It's been long known that they don't.

As I already admitted in another reply, I was wrong about
the silicon carbide wheels on small grinders. To answer
your question, nope, I can't tell the composition of a wheel
at a glance. The dry ones mostly look gray and the water or
oil soaked ones just look dark. Although silicon carbide
ones come in black and green, mine are black, just like
silicon carbide wet/dry paper.

That, as far as I know, is how you identify silicon carbide wheels, aside
from reading the label.. In grinding wheels, I've never seen them in any
colors except for green and black. I've long wondered why, because you
can buy silicon carbide lapping compound in gray, as you've suggested.
I'll eventually check my reference books from Norton to see if they address
that issue.

I don't have a clue what the
red wheels are as they aren't marked.

They are usually aluminum oxide. Could be wrong, though.

I have sharpening
stones, but of the two that retain their packaging, one says
carborundum and the other says silicon carbide (unopened).
Both are the same (of course) and are essentially the same
color as my aluminum oxide grinding wheels. My packaged
grits are silicon carbide and they also have the same dark
grey color.

Well, it's been an interesting thread, and I learned
something.

That's the whole idea here. Share what we know. I commend you for your
polite post acknowledging all our comments.

Harold

On sublimation of diamond. Although 3550 degree C is listed
as a melting point in several references some of the same
references indicate that it actually sublimes. Still, these
references don't fit what appears to be a valid reference
that says diamond breaks down at a much lower temp, and that
reference gave breakdown temps in the presence of oxygen and
in the presence of nitrogen. I believe that was in one of
Bob Powell's references.

Glad there are no hard feelings. I'm still having a hard
time getting my head around the fact that none of my basic
references say anything about diamond dissolving in iron or
any other metal.

"George E. Cawthon" wrote in message
...
big snip---

On sublimation of diamond. Although 3550 degree C is listed
as a melting point in several references some of the same
references indicate that it actually sublimes. Still, these
references don't fit what appears to be a valid reference
that says diamond breaks down at a much lower temp, and that
reference gave breakdown temps in the presence of oxygen and
in the presence of nitrogen. I believe that was in one of
Bob Powell's references.

My lack of education makes it difficult for me to grasp the entire concept,
but I wonder if what's happening at lower temps is the oxygen combines with
the diamond to create CO2.

Glad there are no hard feelings.

I'd like to think I'm a little better than that. I know when I'm wrong I'll
willingly admit so, and offer an apology when required, and admire those
that are willing to do the same. I detest those that slink away silently
when they are wrong, refusing to even acknowledge the error of their ways.
Takes a much bigger man to admit to being wrong, and for that you deserve,
and have, my respect.

Looks like you do know how to "back out gracefully".

I'm still having a hard
time getting my head around the fact that none of my basic
references say anything about diamond dissolving in iron or
any other metal.

That's likely because under normal circumstances it doesn't, unlike precious
metals, that willingly migrate into some other metals when brought into
intimate contact, even at room temperatures. Bear in mind that it's also
a fairly recent discovery, although the phenomenon had long ago been
identified, but perhaps not well understood. Same goes for silicon carbide
dissolving in steel. . One of the references I have, which I am having
trouble locating again, makes mention of the "phenomenon" of the abrasive
apparently dissolving in steel, and they hadn't quite concluded exactly what
the score was. The entire concept was not fully accepted as late as the
mid 40's, apparently. Pretty much all the literature I have came from my
grinding mentor, who was a journeyman grinder at that point in time. While
he was not much as a machinist, he was an outstanding hand at precision
grinding. That seemed to he his calling.

The reaction apparently requires considerable heat in order to occur. That
likely explains why you find small drill pointers that run a diamond wheel,
but likely at slow speed. I'm not sure about that, though.

Does it make you wonder if there would be a lot more diamond in the world if
it weren't for the abundance of iron in nature? Could be diamond would
have formed in lots of places had the carbon not been absorbed by iron.

Harold

In article , George E. Cawthon says...

On sublimation of diamond. Although 3550 degree C is listed
as a melting point in several references some of the same
references indicate that it actually sublimes. Still, these
references don't fit what appears to be a valid reference
that says diamond breaks down at a much lower temp, and that
reference gave breakdown temps in the presence of oxygen and
in the presence of nitrogen. I believe that was in one of
Bob Powell's references.

At this point you are in the range of solid state chemistry.

I used to work with guys who 'did' solid state chemistry,
for things like crystaline lighting phospors, and for
ZrOx oxygen sensors. This was at GTE labs in waltham, mass.

Some of the guys had PhDs, and others simply worked in the
lab and wore those funny pointy hats with stars and plantets
on them. They also tended to have jars around with strange
labels, eye of newt and jaw of toad, etc. It's a very
strange discipline and most of it is art, to go along with
a small amount of science. Things like 'fluxes' that
work at 1600 deg C.

All I *can* say with some certainty is that a) one should not
attempt to intuit the results of an experiment based on
ordinary chemistry rules, and b) trust the experience of
those who have worked in the field.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

John Doe posses an outstanding ability to describe his reasoning
with such detail and yet make such a technical issue clear to the
layman. He makes such a difficult task look so easy. A true
indicator of a real porfessional. We should applaud Mr. Doe for
his significant contribution to this thread.

John Doe wrote in message 8...
(gradstdnt) wrote

You need to look at some very basic chemisty behind the diamond.

BZZZT!