560-003 is a 7 and 8 inch industrial cast aluminum chop saw v-belt spindle pulley. This is the spindle sheave for the K7B 7" and K8B 8" abrasive cutoff saws.
537-024 K7B & K8B abrasive chop saw spindle nut will fit either of these models. Arbor sizes are the same on both the 7 and 8 inch abrasive chop saws regardless the age of the unit.