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

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:

"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.

"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.

"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

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.