H-308 adapter sleeve: complete specifications & mounting data
The H-308 is an adapter sleeve sized 40 x 58 x 36 mm (tapered bore x sleeve OD x width) for a plain 35 mm metric shaft with M 40x1,5 thread supplied with the KM 8 lock nut at 170 g per ISO 2982-1. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 58 mm |
| Width B | 36 mm |
| Fits shaft diameter | 35 mm |
| Sleeve thread G | M 40x1,5 |
| Included lock nut | KM 8 |
| Included locking device | MB 8 |
| Material | Carbon_Steel |
| Mass | 170 g |
| Manufacturer designation | H 308 |
| Standard | ISO 2982-1 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 23.1 adapter sleeves for metric shafts |
| Last verified | 2026-09-30 |
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.
Dimensions in inches & H3-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.283 in |
| Width B | 1.417 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 9 mm |
| Smallest bore in H3-series | 20 mm |
| Largest outer diameter in H3-series | 145 mm |
| Width range across H3-series | 28–77 mm |
| Bore position in H3-series (smallest first) | 5 of 18 |
| Bore above smallest H3-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| H | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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-308 model number is decoded
this sleeve mounts a bearing with a 40 mm tapered bore onto a plain 35 mm shaft; the 58 mm outside diameter and 36 mm width define the tapered seat the bearing is driven onto mounting and dismounting stay purely mechanical: the KM 8 nut drives the taper home, and backing the nut off releases the 40 mm seat without oil-injection tooling the seat taper is 1:12, so each millimetre of axial drive-up removes about 1/12 mm of radial clearance; one turn of the KM 8 nut on the M 40x1,5 thread advances 1.5 mm and takes out roughly 0.125 mm of clearance the sleeve wall is 9 mm thick at the small end — 22.5% of the 40 mm bore — thin enough to contract evenly onto the 35 mm shaft while keeping the seat round under the clamping load a width-to-bore ratio of 0.90 gives a 36 mm tapered contact length; the longitudinal slit lets the sleeve close down radially, so the grip on the 35 mm shaft is purely frictional the 35 mm shaft diameter falls in the small-to-medium band that dominates general industrial use — pumps, fans and light gearboxes with bearings up to the 40 mm bore the H prefix names the basic metric adapter sleeve: a slit 1:12-taper bush supplied complete with the KM 8 lock nut and MB 8 locking washer — bending one washer tab into a nut slot secures the assembly dimensionally this sleeve belongs to 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; the 58 mm OD and 36 mm width follow the ISO 2982-1 boundary plan for that series the delivery includes the KM 8 lock nut and the MB 8 locking washer; drive-up is measured by clearance reduction as the bearing climbs the taper typical applications include conveyor pulley and drum bearing seats, pump shafts in water and process plants and industrial fan and blower impeller shafts adapter sleeves earn their place wherever a tapered-bore bearing must sit at any axial position on a plain shaft — here a 40 mm bore bearing on a 35 mm shaft in industrial fan and blower impeller shafts the sleeve lets the designer use a plain, unstepped shaft and still locate the bearing positively; only one shoulder is needed, opposite the KM 8 nut kit identity for this seat: sleeve H 308 for a 35 mm shaft, 40x58x36 mm taper, M 40x1,5 thread, KM 8 nut with MB 8 washer, catalogue mass 170 g
Typical equipment & failure modes
Common applications
- woodworking saw and planer spindles
- conveyor pulley and drum bearing seats
- marine winch and deck machinery shafts
- cement plant kiln and mill trunnion drives
Known failure patterns
- over-driving the taper eliminates bearing internal clearance entirely; clearance reduction must be measured with feeler gauges, not estimated from nut torque
- hammering the sleeve directly instead of driving through the nut damages the 36 mm slit edge
- interchanging nut families (KM vs KMFE, MB vs MS) across executions loses locking reliability even when the thread appears to fit
- greasing the tapered seat or shaft destroys the dry friction the joint relies on; a lubricated taper can let the whole sleeve spin under load
- mounting without a fixed abutment lets the bearing walk axially; the sleeve needs a shaft shoulder opposite the lock nut
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
- interchanging nut families (KM vs KMFE, MB vs MS) across executions loses locking reliability even when the thread appears to fit
- the shaft must be within h9 tolerance and free of scoring; an oversize or rough shaft stops the slit sleeve closing down and leaves the grip to the thread alone
Frequently asked questions
What shaft size does the H-308 adapter sleeve fit?
H-308 (H 308) mounts on a plain metric shaft of 35 mm and carries a bearing with a 40 mm tapered (K) bore; sleeve OD is 58 mm and width 36 mm.
What does the H 308 designation mean?
H identifies a standard metric adapter sleeve in the H3 series; the size code encodes the 40 mm tapered bore (bore code × 5 mm).
What is supplied with the H-308?
The kit contains the KM 8 lock nut and MB 8 locking washer. Mounting uses a hook spanner, controlling clearance reduction as the 40 mm bearing climbs the taper.
How much does the H-308 adapter sleeve weigh?
The listed mass is 170 g for the sleeve assembly at 40x58x36 mm — about 4.7 g per millimetre of sleeve width.
How is the H-308 mounted on the shaft?
Lubricate the M 40x1,5 thread lightly, screw the KM 8 home, then tighten to the catalogue axial displacement while measuring clearance reduction on the 40 mm bearing, and finally bend the MB 8 washer tab.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 23.1 adapter sleeves for metric shafts on 2026-09-30. Read our editorial & correction policy.