Start with the original brand, full model code, suffixes and drawing revision. Matching shaft diameter alone only identifies a preliminary candidate, not a drop-in replacement.
Compare nut and shaft envelopes, flange bolt patterns, housing fit, retention, shaft-end machining and the available stroke. For rotary and screw-spline assemblies, also check the drive arrangement and support-bearing interfaces.
Review radial and axial loads, torque, moments, speed, acceleration and duty cycle. Confirm accuracy, preload, lubricant and environment. Screw, spline and support-bearing ratings must be evaluated separately where applicable.
Agree the exact drawing, sample quantity, inspection scope and acceptance tests before qualification. Final compatibility and delivery are confirmed for the specified configuration and operating conditions.