5% is usually good for grinding and that's what's in my surface and also my cylindrical grinder. As you go up in the cutting forces you need a higher concentration all the way up to 10 or 11% for heavy machining stainless steel or HT steels in the hard state.
Incidentally the swarf conveyor goes at a slow crawl, so not much stirring there !
I've been experimenting with the various canned cycles in the control - amazingly sophisticated - today's play has been around the 'roughing cycle'. You can define a finished contour on your part that is the shape your final pass with your finishing tool makes, then call up a 'roughing cycle' that makes multiple passes getting closer and closer until your finishing allowance is left.
Two slight detours on the way. Firstly it seems that although 'absolute positioning' moves in X refer to the part diameter, 'relative positioning' refers to radius

so:
G01 X25.00 put the tool on 25mm diameter or actually X=12.5
whereas
G01 X0
G01 U25.00 puts the tool on 50mm diameter or actually X=50 (U being the way relative X moves are defined)
Confusing until you know, and it's nowhere in the book of words that I can find

Second detour involved the tool setting microscope. It has specific co-ordinates stored in the control so that tool offsets can be calculated from its known position. Well they were slightly wrong so I couldn't achieve correct diameter work, until a bit of head scratching and adjustment of the pre-set location

Next onto the threading cycles for a bit of fun
