Rick Dipper wrote:

What type of bit did you use for this, and what type of slate ?
I assume I am not going to be able to copy you using a wood bit, and
some rough slate ?

It was a standard V groove wood bit, and the slate was a chunk of fairly
smoth ex-snooker table slate.

The bit actually looked pretty good at the end of the project, and is
still in use now. Slate's quite soft.

--
Grunff