H-305 adapter sleeve: complete specifications & mounting data

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 23.1 adapter sleeves for metric shafts) · extracted 2026-09-30

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 23.1 adapter sleeves for metric shafts); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the H-305 model number is decoded

a width-to-bore ratio of 1.16 gives a 29 mm tapered contact length; the longitudinal slit lets the sleeve close down radially, so the grip on the 20 mm shaft is purely frictional at 71 g drive-up is still a hook-spanner job on the KM 5 nut slots, with feeler gauges checking clearance reduction rather than torque controlling the fit the KM 5 lock nut carries size index 5, matching the bore-code family of the 25 mm seat; the nut engages the M 25x1,5 sleeve thread over its full width mass 71 g is 2.8 g per mm of bore; the sleeve with its KM 5 nut and MB 5 washer forms the complete 29 mm-wide mounting assembly the 5 mm difference between the 20 mm shaft and the 25 mm nominal seat diameter is bridged by taper contraction as the slit sleeve closes during drive-up, rather than by machining the shaft the 20 mm seat belongs to the miniature tier: the 29 mm sleeve width is barely wider than the bearing it carries, so even a fraction of an extra turn over-drives the taper H 305 carries no hydraulic features — the slit sleeve, KM 5 nut and MB 5 washer do all the work mechanically, which keeps the kit simple for the 20 mm shaft size as part of the medium-section H 3 range, the default seat for 13..K and 22..K self-aligning ball bearings and 222..K spherical roller bearings, this size keeps series-standard proportions: 29 mm width on a 25 mm bore, so the bearing lands at the catalogue axial position the row bundles the KM 5 lock nut and the MB 5 locking washer; dismounting means backing the nut off and drifting the 29 mm sleeve loose along the taper typical applications include electric motor and generator shafts, industrial fan and blower impeller shafts and rolling mill and steel plant roll seats adapter sleeves earn their place wherever a tapered-bore bearing must sit at any axial position on a plain shaft — here a 25 mm bore bearing on a 20 mm shaft in rolling mill and steel plant roll seats the sleeve lets the designer use a plain, unstepped shaft and still locate the bearing positively; only one shoulder is needed, opposite the KM 5 nut full specification chain for H 305 reads 20 mm shaft / 25 mm seat / 38 mm OD / 29 mm width / M 25x1,5 / KM 5 nut with MB 5 washer / 71 g

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• over-driving the taper eliminates bearing internal clearance entirely; clearance reduction must be measured with feeler gauges, not estimated from nut torque
• a fretted or corroded shaft seat cannot be rescued by a new sleeve — the thin wall conforms to the damage and clamping force collapses
• a plain KM nut used without its MB washer has no anti-rotation feature and will unthread under vibration