Adaptor / Withdrawal Sleeves

What is an adapter or withdrawal sleeve?

Adapter sleeves and withdrawal sleeves are tapered steel sleeves used to mount bearings with a tapered bore onto a cylindrical shaft. The bore of the sleeve is straight, so it fits over a plain shaft, while its outside surface is tapered to match the tapered bore of the bearing. As the bearing and sleeve are pushed together along the taper, the sleeve tightens onto the shaft, and the bearing tightens onto the sleeve, giving a secure, concentric fit without the need for an interference fit machined directly onto the shaft.

Although both do a similar job, they are fitted in opposite directions:

• Adapter sleeve - the bearing is pushed up the taper of the sleeve, which stays in place on the shaft. It is held by a lock nut and a locking device on the narrow end of the sleeve, on the opposite side of the bearing
• Withdrawal sleeve - the sleeve itself is pressed into the gap between the shaft and the bearing bore, usually against a shoulder or space. To remove the bearing, a nut on the sleeve’s thread is tightened against the bearing, pulling the sleeve out

An adapter sleeve assembly is usually made up of:

• Sleeve - a slotted, tapered steel sleeve with a thread at one end
• Lock nut - scews onto the sleeve’s thread and pushes the bearing up the taper
• Locking device - a lock washer with tabs, or a locking clip for larger sizes, that stops the nut from loosening

A withdrawal sleeve is usually made up of:

• Sleeve - a slotted, tapered steel sleeve with a thread on its wider end
• Withdrawal nut - used to drive the sleeve out and release the bearing when dismounting, usually supplied separately

Key features:

• Tapered outer surface - usually a 1:12 taper, with a 1:30 taper for some wide series bearings
• Slotted design - the slot lets the sleeve close down slightly onto the shaft as it is tightened
• Fits plain shafts - no need for shaft shoulders or precision interference fits, making shafts cheaper to produce
• Easy positioning - with an adapter sleeve, the bearing can be fitted at any position along a plain shaft
• Easy removal - both types make dismounting easier than removing a bearing from an interference fit
• Controlled fit - the distance the bearing is driven up the taper controls the tightness of the fit and the reduction in internal clearance
• Wide size range - from small sleeves for shafts of around 17 to 20mm up to very large sleeves for heavy industrial
• Hydraulic versions - larger sleeves are available with oil supply ducts and grooves for hydraulic mounting and dismounting

In simple terms, an adapter or withdrawal sleeve is a tapered connector that lets a tapered bore bearing grip a plain shaft firmly, and makes the bearing much easier to fit and remove.

Why are adapter and withdrawal sleeves essential?

Adapter and withdrawal sleeves are essential wherever tapered bore bearings are used, particularly on long shafts, large shafts, and machines where bearings need to be mounted and removed regularly. Fitting a bearing with an interference fit directly onto a shaft requires precise machining and often heavy force or heating, and removing it later can be difficult and risk damaging the shaft. Sleeves avoid these problems by using the taper to create a secure fit that can be tightened and released in a controlled way.

Their main benefits are:

• Simple shafts - bearings can be mounted on plain drawn or turned shafts without precision seats or shoulders, saving machining time and cost
• Flexible positioning - adapter sleeves allow the bearing to be fitted anywhere along the shaft, which is ideal for long transmission shafts and conveyor shafts
• Easier mounting - the bearing is driven up the taper with a nut, instead of being pressed or heated onto the shaft
• Easier dismounting - loosening an adapter sleeve or driving out a withdrawal sleeve releases the bearing without heavy force, reducing the risk of damage to the shaft and bearing
• Controlled internal clearance - the drive-up distance sets the bearing’s internal clearance accurately, which is important for spherical roller bearings and self-aligning ball bearings
• Secure, concentric fit - the taper centres the bearing accurately on the shaft and holds it tightly under load
• Shaft protection - if the bearing fails, the sleeve takes much of the damage, helping to protect the shaft
• Reduced maintenance time - bearings can be replaced more quickly, cutting downtime
• Standardised sizes - sleeves are made to international standards, so they are easy to source and interchangeable between brands

These qualities make adapter and withdrawal sleeves important in many industries and applications, including:

• Conveyors and material handling - pulleys, drums, and long conveyor shafts
• Fans and blowers - industrial fan shafts mounted in Plummer block housings
• Mining and quarrying - crushers, screens, conveyors, and heavy rotating equipment
• Paper and printing industries - drying, cylinders, rolls, and long shafts
• Steel and metal processing - rolling mill equipment, roller tables, and heavy drives
• Cement and aggregates - kilns, mills, crushers, and vibrating screens
• Agricultural machinery - long drive shafts and transmission shafts
• Pumps, mixers, and agitators - where bearings must be removed for maintenance
• Marine and power generation - large shafts and rotating equipment
• Woodworking and textile machinery - long shafts and rollers 

The main types of adapter and withdrawal sleeves

Adapter and withdrawal sleeves are usually grouped by type, dimension series, mounting method, and shaft size standard

Adapter sleeves:

• Standard adapter sleeves - the most common design, supplied with a lock nut and lock washer, used with self-aligning ball bearings, spherical roller bearings, and toroidal roller bearings
• Adapter sleeves with locking clip - larger sizes use a lock nut with a locking clip that fits into a slot, instead of a lock washer
• Hydraulic adapter sleeves - larger sleeves with oil ducts and grooves, allowing oil to be injected between the surfaces to reduce friction during mounting and dismounting
• Adapter sleeves for inch shafts - designed to fit imperial shaft sizes while mounting standard metric bearings
• Adapter sleeves for insert bearings - smaller sleeves used with tapered bore insert bearings in housing units

Withdrawal sleeves:

• Standard withdrawal sleeves - pressed into the bearing bore and held against a shoulder, space, or shaft nut, then removed using a withdrawal nut
• Hydraulic withdrawal sleeves - larger sleeves with oil ducts and grooves, making it easier to press the sleeve in and drive it out
• Withdrawal sleeves for wide series bearings - designed with a 1:30 taper for wide spherical roller bearings

By dimension series:

• H2 and H3 series adapter sleeves - used with light and medium series bearings such as self-aligning ball bearings and spherical roller bearings
• H23, H30, H31, H32, and H39 series adapter sleeves - used with wider and larger spherical roller bearings and other heavy-duty bearings
• AH series withdrawal sleeves - matching withdrawal sleeves for the same bearing series
• AOH series withdrawal sleeves - hydraulic withdrawal sleeves for larger sizes

Accessories:

• Lock nuts - standard nuts for securing the bearing on the sleeve, often identified by KM references
• Lock washers - tabbed washers that lock the nut in place
• Locking clips - used with larger nuts
• Hydraulic nuts - used to push the bearing up the sleeve with oil pressure, making mounting large bearings much easier and more accurate
• Withdrawal nuts - used to drive out withdrawal sleeves during dismounting

How to choose the right adapter or withdrawal sleeve?

Choosing the right sleeve means matching it carefully to the bearing, the shaft, and the way the bearing will be mounted and removed. Work through these points in order:

• Bearing type and reference - check the bearing has a tapered bore, usually shown by the suffix K, or K30 for a 1:30 taper. The bearing reference will point you to the matching sleeve series
• Taper - make sure the sleeve taper matches the bearing taper, either 1:12 or 1:30
• Shaft diameter - measure the shaft accurately. The sleeve bore must match the shaft, which is usually smaller than the bearing bore
• Metric or inch shaft - choose a sleeve designed for the correct shaft size standard
• Adapter or withdrawal sleeve - choose an adapter sleeve for plain shafts and flexible positioning, or a withdrawal sleeve where the bearing sits against a shoulder or spacer and space for a lock nut is limited
• Housing and space - check there is room for the lock nut or withdrawal nut, and that the sleeve and nut fit inside the housing, such as a Plummer block.
• Bearing size and mounting force - for larger bearings, consider hydraulic sleeves or hydraulic nuts to make mounting and dismounting easier and safer
• Locking method - choose a lock washer for smaller sizes or a locking clip for larger ones, following the manufacturer’s recommendation
• Axial location - decide whether the bearing must be located against a shoulder or spacer ring, especially in locating bearing positions
• Operating conditions - consider loads, vibrations, temperature, and corrosion, and choose stainless steel or special sleeves where needed
• Mounting method - plan how you will measure the drive-up, such as measuring radial clearance with feeler gauges, measuring axial drive-up, measuring the nut tightening angle, or using a hydraulic nut with a dial gauge
• Standards and brand - choose sleeves from a reputable manufacturer that match the international standard dimensions, ensuring a correct fit with the bearing

Essential references and sleeve ranges

Adapter and withdrawal sleeve references follow a standard numbering system used by many major manufacturers.

Main adapter sleeve series:

• H2xx series - used with light series bearings, such as the 12xx series self-aligning ball bearings
• H3xx series - used with medium and wide bearings, such as 22xx and 13xx series self-aligning ball bearings and 222xx series spherical roller bearings
• H23xx series - used with wider bearings, such as 23xx series self-aligning ball bearings and 223xx series spherical roller bearings
• H30xx, H31xx, H32xx and H39xx series - used with larger spherical roller bearings and heavy-duty applications
• OH series - hydraulic adapter sleeves for larger sizes, with oil supply features
• Inch-sized sleeves - often identified by a prefix or suffix showing the inch shaft size, depending on the manufacturer

Main withdrawal sleeve series:

• AH3xx and AH23xx series - used with medium and wide bearings
• AH31xx, AH32xx and AH24xx series - used with larger spherical roller bearings
• AOH series - hydraulic withdrawal sleeves for larger sizes

Understanding the code:

The last two digits of the sleeve reference usually match the bore code of the bearing, not the shaft size. For codes 04 and above, multiplying by 5 gives the bearing bore in millimetres, so 08 is a 40mm bearing bore. The shaft diameter is smaller than the bearing bore because the sleeve adds thickness. For many smaller sizes, the shaft is about 5mm smaller, but the difference increases with size.

FAQ - All you need to know about adapter and withdrawal sleeves

What is the difference between an adapter sleeve and a withdrawal sleeve?

With an adapter sleeve, the bearing is pushed up the sleeve and held by a lock nut on the other side. With a withdrawal sleeve, the sleeve is pressed into the bearing bore, usually against a shoulder or spacer, and later pulled out with a withdrawal nut.

Which bearings use sleeves?

Bearings with a tapered bore, mainly self-aligning ball bearings, spherical roller bearings, toroidal roller bearings, and some insert bearings

How tight should the bearing be on the sleeve?

It should be driven up a specific distance, which reduces the bearing’s internal clearance by the amount given in the manufacturer’s catalogue. 

Why is the shaft smaller than the bearing bore?

The sleeve sits between the shaft and the bearing, so the shaft must be smaller to leave room for the sleeve’s thickness.

Can adapter sleeves be used on worn shafts?

They are more tolerant than direct interference fits, but the shaft still needs to be within the recommended tolerance. A badly worn shaft should be repaired or replaced.

What causes sleeve and bearing problems?

Common causes include incorrect drive-up, mismatched tapers, wrong shaft size, dirt on the mating surfaces, loose lock nuts, missing lock washer tabs, and damage during mounting or dismounting.