On Wed, 26 Dec 2007 08:25:11 GMT, "Harold and Susan Vordos"
wrote:


wrote in message
.. .
On Wed, 26 Dec 2007 02:05:42 GMT, "Harold and Susan Vordos"
snip---

Why is one white and one grey? The Al2O3 white one is meant for HSS
and apparently does a better job on that, so what is the grey one
meant to do?

Sorry----I failed to address your question about the gray wheel.

I think you'll find it is bonded harder than the white one, so it is
intended for grinding soft materials, such as mild steel, or even high
carbon steels in the annealed condition. The rule of thumb is hard wheels
for soft materials, and soft wheels for hard materials. It's all about how
long it takes for the wheel to shed dull bits to re-sharpen itself.

Hardness, in grinding wheels, is not related to the media, it's related to
how the wheel is bonded. A J wheel is softer than an M wheel.

Thanks for all your help, Harold.

I'm going to take my 4 wheels in to Australian Abrasives to ask
exactly what they are and to see if they have a diamond wheel that
would suit my application and my purse.

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.

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?

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.

I wonder if any Australians here know where is a good place to get a
diamond wheel.

jack