Abstract: An apparatus for fixing the longitudinal position of a shaft, e.g., a valve stem, within the bore of a body, e.g., a valve body comprising a shaft having a plurality of peripherally extending, generally equally spaced, discrete grooves, the grooved portion of the shaft being received in the bore, a stop being provided internally of the bore, a washer having an inwardly tapered abutment surface engaging the stop, a split ring received on the shaft and engaging the inwardly tapered abutment surface, the apparatus further including a gland assembly including a second washer for engagement with the first washer, the gland assembly urging the second washer against the first washer, the split ring being forced into engagement with the abutment surface and into a groove adjacent the abutment surface.