Clamping D-hubs are a fantastic solution for transferring power from a shaft to the hub. While conventional clamping hubs with a cylindrical bore rely solely on clamping force to keep the hub from slipping on the shaft, the new D-hubs have a D-shaped bore to perfectly match a D-shaft of the same diameter. This means that, even without tightening the pinch bolt, the hub is prevented from slipping on the shaft. The 6-32 pinch bolt, when tightened, will tighten the hub around the D-shaft for added security and to keep the D-hub from sliding up and down the shaft. The hubs are fully machined from 6061 T6 aluminum so that we can hold tight tolerances and ensure they fit perfectly with mating parts. The 0.770" Actobotics® pattern is tapped into the face of the part so that you can install gears, wheels, pulleys, sprockets, etc. with 6-32 machine screws.