Complete Roller Bearing Size Chart

HK series needle roller bearings are thin-walled drawn cup bearings (stamped outer ring)—compact and space-saving, suited to limited radial space with moderate loads. NK series needle roller bearings are non-separable, machined solid-outer-ring bearings with a thicker wall and higher load capacity, suited to higher radial loads. Selection mainly comes down to available space versus load. Share your shaft diameter, outer-diameter limit, and load conditions, and ISK can help evaluate the more suitable series.

The key difference is whether an inner ring is included. NK series needle roller bearings have no inner ring—the needles roll directly on the shaft, so the shaft surface must be hardened and precision-ground to serve as a raceway. NA series bearings include an inner ring, making them suitable when the shaft can't be used as a raceway, or when higher running accuracy and precise shaft alignment are needed. If your existing shaft material or process can't act as a raceway, the NA series is usually the choice—share the shaft specs and ISK can help assess.

HF series needle roller bearings are one-way (freewheel) clutch bearings that allow free rotation of the shaft in one direction and lock in the opposite direction—commonly used in overrunning clutches and other mechanisms requiring one-way drive or backstop function. When selecting, confirm the locking torque (Torque Ma), the locking and free-rotation directions, and the speed requirements for both shaft-rotation and outer-ring-rotation conditions. Share your actual drive scenario and ISK can help assess.

CF series needle roller bearings are stud-type cam followers whose outer ring contacts the cam or track directly and rolls along the cam profile—commonly used in conveyor systems, cam mechanisms, and other motion-transmission applications. Beyond bore, outer diameter, and width, selection also depends on stud length (L), load direction, and running speed. Share your mechanism layout and load conditions, and ISK can help confirm a suitable part number.

A needle roller bearing dimension chart's key values include bore (Fw / d), outer diameter (D), width (C / B), dynamic load rating (Dynamic C), static load rating (Static Co), and limiting speed (RPM). Bore, outer diameter, and width determine whether the bearing fits the mechanism; dynamic and static load ratings correspond to load capacity while running and at rest; and limiting speed is a reference ceiling for avoiding excessive heat and premature wear—each should be judged together with the actual operating conditions.