Boston Gear FC20-3 4 Jaw Coupling Hub With Keyed Bore

The Boston Gear FC20 series 3-jaw coupling hub is a steel, half-hub designed for FC20 straight-jaw couplings with a 3/4 in bore. It features a 1.7500 in hub diameter and a hub length of about 1-1/8 in, delivering a compact footprint for moderate-speed drives. The 3/4 in bore accommodates a 3/4 in shaft and includes a precision keyway sized 3/16 in wide by 3/32 in deep for positive torque transmission, paired with a setscrew for secure clamping in the mating half. Constructed from alloy steel, the hub tolerances are geared toward high-torque performance, and the FC20 family is rated up to approximately 1,750 RPM, making it suitable for servo or stepper-driven applications requiring a rigid, aligned connection. Boston Gear also offers FC20 hubs in additional bore sizes and provides custom bore options on request.