Most crankshafts show some degree of bend, and need to be straightened before regrinding.
The crankshaft is set up on a xxxxx and measured for bend. This will be particularly noticeable on shafts that have a badly fouled big end bearing.
We have two methods of straightening:
1. Regrind in our 2m offset machine. The shaft is set up in the machine throw blocks for the crank pins to be reground around their own access
2. Regrind in our Prima centreless grinder which allows the grinding wheel head to follow the crankpin.
The oil seal tracks will be lightly ground to ensure they are concentric with the main bearings, and the flywheel flange is also reground to ensure minimum runout.
All journals are subsequently polished on a finisher using specialist belts and compounds which leaves a bright surface finish.
On completion, hardness testing can be carried out if a bearing has been overheated as this can reduce the hardness values. This is advisable as such loss of hardness can result in premature wear or even breakage.
We also can employ the patented Gleason Crankshaft Reclaimation process. Ask for more details.