I have three grinders " hand held electric rasp for shaving small chips of hoof from a cows claw by a professional claw technician " set on the crush when working. They are 900 watt Metabo grinders with 6 bit 3mm trim tec discs. All blades all face away from the operated. All grinders are bandaged up so if heavily soiled when working a new bandage can be applied. We have a spare grinder for back feet as that grinder has twice the work load and will need replacement tips sooner than the front two grinders, Aluminium guards are added to protect hands from hoof discharge and all grinders have start buttons on the top of the grinders so for more controlled switching.
The grinder is placed that what ever the high of the crush the grinder can be easily to hand.
The front grinders are located best for when the crush is a full height for the trimmer to collect and replace yet still out of the working zone