In-situ Straightening (Peening) of a Bent Crankshaft

The pictures below show the straightening and subsequent machining of a bent crankshaft, carried out by our specialists in Singapore. All work was carried out in-situ. The crankshaft was found bent following a crankpin bearing failure.

The crankshaft belongs to a 12-cylinder, 40-bore engine installed on a dredger. A straightness check revealed that its run-out was 0.18 mm, which is far beyond the acceptable threshold.

Our specialists therefore carried out in-situ straightening by peening the shaft. Peening is a cold-process that consists of applying a small force repeatedly to the correct places to bring the shaft back to its original straightness. This took one day and resulted in an improvement of the run-out from 0.18 mm to 0.03 mm.

After straightening, our specialists machined the crankpin to -7.00 under-size and then polished it.