Wouldn't want to venture a guess on the Grader. Wth regular stones I use wet/dry sandpaper glued to a piece of glass and rub the stone on the now flat sandpaper.
If the wheel is slipping:
First, make sure the nut on the grindstone is tight.
If it is and you can still stall the wheel too easily, take off the Honing wheel and see if the motor shaft keeps spinning when you stop the drive wheel.
If the motor stalls too easily, the motor itself likely needs repair or replacement.
If the motor keep spinning, clean the motor shaft with mineral spirts or a similar grease remover. Then refresh the rubber surface of the drive wheel by lightly holding fine sandpaper or emery cloth to the surface for a few seconds as it spins. The book says that if the grindstone stops it should stop the motor, so if you still get slippage apply a little more pressure with the sandpaper on the moving rubber wheel until you are happy with the grip.
If the wheel is slipping:
First, make sure the nut on the grindstone is tight.
If it is and you can still stall the wheel too easily, take off the Honing wheel and see if the motor shaft keeps spinning when you stop the drive wheel.
If the motor stalls too easily, the motor itself likely needs repair or replacement.
If the motor keep spinning, clean the motor shaft with mineral spirts or a similar grease remover. Then refresh the rubber surface of the drive wheel by lightly holding fine sandpaper or emery cloth to the surface for a few seconds as it spins. The book says that if the grindstone stops it should stop the motor, so if you still get slippage apply a little more pressure with the sandpaper on the moving rubber wheel until you are happy with the grip.