Harold and Susan Vordos wrote:

"Martin H. Eastburn" wrote in message
. ..
snip----



Saw blades have diamond pressed into slots on the circumference. These

slice through rock and cements...

I have sliced through tons of material. The diamond doesn't absorb into

the host material (the tool)

but I suspect the very highest temps are only at the tip where atoms are

stolen.

The host material isn't where the diamonds are mounted. There's usually an
alloy that becomes the bonding agent, and it doesn't have an affinity for
carbon. There is no transfer of carbon for that reason.


Is it simply a matter of cost ? - the carbon is absorbed a little and the

tool becomes used up?

With grinding wheels that are dressed by diamond, the diamond gets dull and
ceases to cut easily with prolonged use. If you're familiar with dressing
grinding wheels, you understand why the typical diamond dressing tool mounts
the diamond at an angle instead of at right angles. That way, all you have
to do is rotate the diamond slightly to present a sharp corner of the
diamond to the wheel so it cuts cleanly instead of burnishing the wheel.
It would be much the same with diamond grinding wheels. The slightest
dulling by absorption renders the diamond far less affective. The diamond
may not be used up, but it gets dulled to the point where it takes
considerable pressure to get it to cut, and you risk tearing the diamond out
of the matrix as a result.

Maybe the data is simply old economics. Diamond drill heads bore through

iron cobalt deposits and

other iron rich layers for many years in well drilling. So maybe research

needs to look at this

again with a different point of view.

Martin


Martin, I think you're overlooking the fact that well drilling takes place
at much lower speed, so low that the critical temperatures are never
approached.
Consider a 5000 foot hole - not the deepest by any means. That is 5000 feet
of drill pipe above it. Then the heavy drill head of three rotating cutters.
The pressure is very high. The temperature is static vary high and is boosted
by the grinding of rock with rock. Forced water or fluid is driven down the tube
through the center of the cutter (sounds like a mill doesn't it) and the now
dirty, grimy dust is forced upward around the sides of the drill tube.
I suspect the point contact temperature and pressure is extremely high. Few
really know as much of it is protected under patents. Bound to be some in
theory books and now the web.


I think the whole issue is cost of tool and what one can do without it.
There are very good replacements that can replace diamond.

Martin

I'm not convinced anyone is suggesting diamond can't be used for cutting
ferrous metals, but there are inherent hazards involved, one of which is the
shortened life of the tool, especially if it's at accelerated speeds. The
lesson that's important for the home shop types to learn is that diamond
grinding wheels should never make contact with iron or iron alloys at high
speeds in order to preserve the diamond. The slightest contact affects a
wheels ability to cut. So much so that the wheel often requires a dressing
in order to restore a wheels ability to cut freely. I'm sure wheel loading
is a part of the reason, but dressing the wheel takes life out of it, so
it's a good idea to minimize dressing. You can do that by avoiding grinding
steel.

Harold





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