The blade from our current Craftsman mower is on the right:
The other two came from our previous Craftsman mowers.
Stipulated: Sears sources their mowers from various suppliers, but it’d be great if everybody could agree on a single blade mount and be done with it.
For the record, a 5/8 inch socket works fine. One could surely use a 16 mm socket in a pinch.
Wear leather gloves to prevent a nasty gash from the stamped-steel muffler shroud as you pull the sparkle plug cap to avoid an absolutely impossible engine startup while you’re wrenching under the deck.
Replace the air cleaner while you’re at it.