In article , Jeff Wisnia wrote:

If you knew which way the grinding plate rotated when operating, it's a
safe bet that the nut would come off by turning it in the opposite
direction.

It's an even better bet that the nut would come off by turning in the *same*
direction. Think about how the arbor nut threads onto a portable circular saw,
for example, or on a table saw or radial arm saw.