Main Bearing Journal Repair

Main Bearing Journal Repair

In-Situ Machining Solutions (UK) Ltd are specialist and market leaders in on-site Main Bearing Journal repairs, offering an unrivalled Grinding service allowing repairs to take place without the need to remove the Crankshaft. Specially designed and manufactured Grinding machines are deployed for use with our highly skilled Engineers to undertake Grinding operations and restore Main Bearing Journals back to OEM tolerances and specifications. The process can take place on land or aboard a vessel whilst at sea and dramatically reduce downtime and costs associated with replacement options.

4-Stroke Engines, 2-Stroke Engines and Compressor shafts are all areas in which In-Situ are world leaders and offer an unrivalled service. Vast experience gained through innovation, investment, R&D and field trails allow In-Situ undertake the most complex Crankshaft machining projects in the shortest time possible.


In-Situ provide the most technologically advanced equipment and In-Situ Main Bearing Journal Grinding techniques, gaining the worldwide reputation as shaft, journal and Main Bearing specialists. Our highly skilled and motivated Engineers offer a precision on-site, on-board and off-shore Crankpin machining service led by a dedicated and experienced management team. Damage to Crankshafts can vary in severity depending upon a variety of factors. In-Situ can supply services for the analysis of the damage and rectification of both the main Journals and the Crankpins.

The service include an annealing process to reduce hard surfaces as high as HB 750 on one piece forged steel Crankshafts that have not been induction hardened or nitride. Our advanced Main Bearing Grinding service is offered to all sectors of industry including, Power generation, marine, steel production, petrochemical, offshore oil & gas, transportation, food production and defence. We work closely with OEM’s achieving the high tolerance demands required by these manufacturers.

Main Bearing Grinding Process

Failure Assessment & Inspection

The process includes multiple services in which the severity of a failure or condition of the main bearing Journal is assessed. This allows a plan to be put in place for Grinding operations to take place. The process may include all or some of the following services: Crack Detection, Hardness Testing, Geometric Tolerance Checks, Run Out Checks and Exploratory Grinding.


A specially manufactured grinding machine is utilised to grind the Journal to remove any damage or wear and restore OEM specified tolerances to the diameter, radii and oil holes.

Superfinishing & Polishing

A process in which a specialist piece of equipment holding a carborundum stone oscillates from side to side around 30 times a second to flatten off the surface of the main bearing journal after the grinding process. The journal is then polished to restore the OEM specified surface finish.

Additional Services

Heat treatment

Annealing of the Crankpins can be undertaken to reduce heat induced hardness within the journal that is above OEM specification. This service is undertaken via a resistance heat treatment method in which a process of controlled heating, soaking and cooling of the effected Journal with ceramic blankets is undertaken.

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    Relatable Industries

    We work across several different industries and we provide a 24/7 worldwide service for our clients.
    Oil & Offshore
    Marine & Ship Building
    Mining & Machinery
    Power Generation

    Get In Touch With Our Team Today
    Office Contact Details: +44 (0) 1788 572777
    Out Of Office: Dan +44 (0) 7398 231720 Mick +44 (0)7876453285

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