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I'm assuming that diamond wheels are basically flat steel plates with
diamonds bonded to the side face of the wheel opposite the motor.
I will try to rig up a table and jig to hold tools at the correct
angle to this flat surface.

They are typically made of aluminum, not steel. The wheel I use, which is
commonly found on diamond grinders, is 6" in diameter, and 3/4" thick, It
has a counterbore 5/16" deep, 4-1/2" diameter. There is a 1-1/4" bore, and
a bolt circle, countersunk, for mounting the wheel. The working face is
3/4" wide, and can be obtained in either 1/16" or 1/8" thickness of diamond.

It's best to build a table that extends part the face of the wheel on the
outside, so the tool is supported when grinding the sides. Both sides of
the wheel (left and right) will be used, depending on the handing of the
tool in question, so it's important that the motor be able to be reversed.
The table should be adjustable between 0 degrees and up to 10 degrees of
angle. It need not have calibrations, just be adjustable easily. You'll
find you often change the angle on the table as you grind different features
of a given tool. Table centerline should be slightly below the centerline
of the wheel, so the wheel contacts the tool at the centerline. I'd
suggest 3/8", unless you use large tools. if you intend to grind on up to
3/4" tools, then I'd shoot for 1/2" below center with the table. That way
you won't be too low when grinding on small tools.


What would be an ideal speed for a diamond wheel, and how much water
is required if indeed it is? Would a drip a second, or similar be
adequate, or is it best to flood the area?

Ideal speed would be maximum allowable speed of the wheel, but you'll find
that a 3,450 or 3,600 RPM motor will provide excellent service. A slower
motor will function, but expect slower results. I suggest sticking with
the 3,000+ speed.

Regards coolant, the grinder is best built with a pan, which would have a
drain that returns the coolant for reuse. A chemical additive will keep
it from rusting. I use a small circulating pump, and feed the wheel at
its center, using some 3/16" copper tubing. I have a valve in the circuit
to control flow. I keep a steady stream, although it's a small one.
Drops tend to allow heating and cooling instead of a constant cooling. I'd
personally advise against a drip system, although I'd be first to agree they
work. They're just not quite adequate if you're roughing a tool, which is
often required because of edge chipping. You're also subject to thermal
shock if the interval between drips gets spread out to far.


I've got a couple of extremely cheap 4" diamond cut-off wheels for a
4" angle grinder. One is labelled for wet cutting, and the other with
radial cutouts, for dry cutting of glass and ceramics and so on.
I wonder if these might be used for some rough tool shaping if the
angle grinder were clamped securely to a bench. The diamonds appear to
be rather coarse, and far apart, and the wheels are designed for max
rpm of 14500.

If they're the HF variety of wheel, I'm familiar with them, having purchased
a set for use in the house building project that seems to consume all my
time. The problem you'll face with them, unless you have the one that
has no serrations, is the bumpy grind. Carbide doesn't take kindly to
interrupted cuts, so you could expect some chipping if you use them for that
purpose. They're not great for use on edge because there's a steel band
in the center of the wheel that won't cut. In abrasive materials (concrete,
for instance), the band is ground back in the course of use. Carbide would
likely act as a bearing, so the blade wouldn't cut well once that center
section was in contact with the tool. In general, I'd say they're not well
suited, but you might explore their use for grinding a chip breaker.

As an aside, I can send you a couple pics of my home made grinder. They'd
be small, under 100 kb in size. I'm on a dialup. Let me know if you'd
like to have them.

Hope some of this helps!

Harold