R21 Keyless Locking Device

The table lists 14 sizes: shaft diameters Ø15–Ø60 mm, hub bores Ø25–Ø70 mm, transmissible torque 77–1379 N·m at the specified screw tightening torque. Intermediate or larger sizes are machined from solid to your shaft and hub dimensions.

R21 keyless locking device: tightening the locking screws presses the inner and outer taper rings together, expanding radially against shaft and hub — zero-backlash bidirectional torque, self-centering, repeatedly removable; similar to JB/T 7934 type Z19B. Recommended fits: shaft h8 / hub H8. The table lists dimensions, transmissible torque and axial force, contact pressure and DIN 912-12.9 locking screw sizes. All R-series keyless locking devices work the same way — tightening the screws presses tapered rings together, clamping shaft and hub with zero backlash, self-centring and repeatable removal — and the types differ in construction: outer diameter for a given shaft, overall length, whether the hub needs a shoulder or a flange, and the force the screws must be tightened to. Compare the Ø d / Ø D / L columns and the transmissible torque Mt on this page against your shaft and hub, and pick the smallest type that fits.

Yes. Everything on this page is made to drawing, and the table is only the standard-size subset of the catalogue. Minimum order quantity is one piece — we routinely make single replacement parts for OEMs whose original supplier has discontinued the item. Send a DWG, STEP or PDF drawing (or a sample part): you get a formal quotation within 24 hours after the information is complete, and the first article ships within 30 days of drawing approval, with inspection records.

Send: shaft diameter and tolerance, hub bore and outside diameter, available hub length, torque to be transmitted (and any axial load), speed, whether the hub can have a shoulder or flange, and quantity. We will confirm the type and size and check surface pressure against your hub material.