Thank you for that. It seems that the dimensions of those cutters must mostly be based on imperial measurements even though they are expressing in mm - would that be right?
I have heard that I should limit the plunge depth to 75% of the tool diameter. I plan to extract the shavings via vacuum - most probably hand held close to the bit. One aspect of what I want to do is to remove most of the inside of a small block of wood measuring roughly 200 x 80 x 40 mm - I guess I could use the down cut bit first for the extremity of this cut and use an up cut bit to remove the bulk where the surface tearing would be irrelevant. Is that kind of process common practice?
Kind regards
Richard