The 1/4″ x 1/4″ Steel (Black Oxide) Set Screw Coupling is a simple and economical rigid coupling designed to connect two hex shafts for reliable torque transmission. Precision-machined from black oxide steel, it uses set screws to secure the coupling directly to the shaft surfaces, providing a cost-effective solution where frequent adjustment is not required. Available with or without keyways, the coupling can also be fitted with a second set of screws to significantly increase load capacity.