Slew Bearing Upgrade

Ascribe Engineering personnel has extensive experience in slew bearing assessment, monitoring, and machine support during slew bearing replacement.

In preparation for a machine upgrade, Ascribe Engineering was commissioned to provide expert assistance with the procurement of an upgraded large diameter slew bearing and the support of the machine.

  • Date: 2019
  • Client: Undisclosed
  • Project Type: Bulk materials handling

About this Project

Ascribe Engineering has specialist engineering knowledge on large diameter slew bearings. The particular bearing in question was originally a roller/ball combination that previously failed after some 5 years of operation. Ascribe Engineering provided assistance in the procurement of an upgraded triple row roller slew bearing.

In this instance, the bearing pads had also been incorrectly machined whilst the superstructure was supported under three external jacks. This has likely led to an increase in the peak roller load, resulting in a reduced life.

Ascribe Engineering offered engineering assistance to re-profile the bearing pads whilst the superstructure was evenly supported.

Services included:


  • Provision of a detailed technical purchase specification
  • Onsite inspection of existing slew bearing and jacking arrangement
  • Engineering layout and preliminary concept design for multi-jack uniform support arrangement
Premature failures of medium to large diameter precision slew bearings is often seen by Ascribe Engineering. Generally, the root cause lies in the selection of the bearing where the roughness factor chosen does not adequately allow for the bearing pad flatness usually stemming from the poor support of the machine.

The Australian design code for bulk handling equipment AS4324 part 1 provides little guidance to the designer for the selection of mechanical items such as large precision slew bearings.

Ascribe Engineering can provide expert advice in relation to slew bearings including:


  • Calculation of design loads
  • Selection of roughness factor
  • Upgrades of existing slew bearings
  • Calculation of B10 bearing life
  • Calculation of slew hold down bolt capacity
  • Procurement specifications
  • Audit of slew bearing selection and design
  • Engineering of machine support during slew bearing replacement
  • Failure investigation

Roller Circle Inspection

Ascribe Engineering undertook an inspection of the rails of a dragline.

Dragline Stability

Engineering advice on the stability and centre of gravity of a dragline.

Shaft Torque Measurements

Torsional stress measurements on rotating shafts.

Contact Us

8/83 Leichhardt St, Spring Hill, QLD, 4000