Crankpin Machining

A Crankpin or Large End Journal (the eccentric part of a crankshaft) is a common failure point in marine and industrial diesel engines.

It is the most highly stressed of the bearing surfaces and as such is prone to failure far more often than the main journals.

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Nicol & Andrew recognised the value of carrying out repairs to Crankpin Journals in-situ back in 1950 when we developed and patented the Orbitool system of crankpin machining. All subsequent methods used by companies world-wide have been derived from this sytem.

The machining equipment has been developed over the years to remove metal more accurately and more importantly far more quickly.

Machining and polishing of crankshaft crankpins is carried out to OEM tolerances and surface finish specifications. That is generally for Crankshaft Journals: -

  • Shaft straightness to shaft axis within 0.15mm/metre
  • Roundness, concentricity and parrallelism within 0.02mm
  • Surface finish better than 0.2µm Ra

We have performed this type of in-situ repair many hundreds of times over the years and we guarantee total customer satisfaction.

We cover standard crankshaft diameters from 75mm up to 1000mm and much larger if required. Our patented Orbital Equipment rotates around the damaged crankpin journal using the Radii as a datum.

If you have a damaged damaged crankshaft radius this is normally not a problem. We have a proven proven ability to re-machine most damaged radii in alignment with the original shaft centreline using our false journal technique and precision electronic levels.

This method can even cope with slight vessel movement so the vessel does not need to be removed to a dry-dock for this operation.

We Can also Hone and Polish your crankpin if the damage is slight or you just want to improve the surface finish to 0.2µm Ra.