Weldahub W 3/4" ID Round OD is 1.625" or 41.28 mm

Weldahub W 3/4" ID Round 000200125.  Has a 3/16" keyway and 2 set screws, OD is 1.625" or 41.28 mm. 

Fits both 35 A Weldasprockets and 41 A Weldasprockets (except for the 41 A 12, 13, 14 and 15 tooth).