R” Hubs – For Assembly With “AR” Plate Sprockets
Round bore hubs have regular keyway and 2 setscrews. 
Square, Hex and Splined bore hubs possess set screws only.
Ready Sprockets are an assortment of sprockets and hubs drilled and tapped for READY SPROCKET HUB – TYPE R simple, convenient assembly with regular hex head cap screws. For No. 35 through No. 100 Chain, with share finished bore hubs to accommodate shaft sizes through 2-3/4″ diameter, and also a variety of square, hex, spline, and tapered important bores.