Ok, I feel really stupid asking this but I'm perplexed and I know the CBN wheel isn't tight so I'd rather be safe.

I recently got my first bench grinder (Rikon 1HP) with CBN wheels to sharpen my woodturning tools. I realize the nut on the left is left threaded and the one on the right is normal thread. But since I need to move both nuts in the same direction to tighten how do I get the shaft of the grinder to not rotate so I can properly get both nuts tight?

Thanks in advance!