Silverline Left Hand Threaded Tapered Spindle 12.7mm (1/2)

Amazon

Threaded taper from 6.35 mm (1/4") to 19.05 mm (3/4") Taper working length 65 mm Allows wheels to be stacked to required thickness For use with buffing wheels and wire wheels 1/2" left-hand threaded bore for connection to grinders, Weight: 0.4850169764 pounds, Manufacturer: SLTL4

Electrical World

Threaded taper from 6.35mm (1/4") to 19.05mm (3/4"). Taper working length 65mm. Allows wheels to be stacked to required thickness. For use with buffing and wire wheels. 1/2" left-hand threaded bore for connection to grinders.

ManoMano

Threaded taper from 6.35mm (1/4") to 19.05mm (3/4"). Taper working length 65mm. Allows wheels to be stacked to required thickness. For use with buffing and wire wheels. 1/2" left-hand threaded bore for connection to grinders.