Planar Knives

Hi Folks, it's been a while but...

...Jeff will perhaps remember these discussions from another universe but I think it's at least worth a canter through the thinking.

I own a Startrite SD300 Planar/thicknesser which has 12" knives.  The steel is very hard, don't know which alloy exactly but at the very least HSS.  Using water cooled grinders simply didn't work as they're not tough enough to remove the steel.

If I could mount it and run it through the PE and deliver an even grind across the width I'm pretty sure the linisher would cope with the hard steel.  So the question is (and I haven't even tried it yet so completely in the dark and this is theory only)....could I just angle the table to the right bevel...shove the knife on and gently and carefully grind from side to side until all 12" was touched up?

I'm talking freehand here.  Or is the need to keep planar knives very evenly balanced too important to risk just freehanding them in the way I suggest.

Does anyone know if this has been tried?

Many thanks