Technical Report
On-Site Crankshaft Grinding
Engine Type
Crankshaft machining was carried out on a Daihatsu DK‑28, 8-cylinder medium-speed diesel engine.
Work Scope
On-site crankshaft grinding was performed using portable in-situ machining equipment. The operation involved the machining of eight crankpin journals in order to restore correct geometry, surface condition, and dimensional tolerances.
Initial Condition
Initial measurements indicated crankpin diameters ranging between 234.85 mm and 234.95 mm. All journals presented ovality and diameter deviation, requiring corrective machining.
Machining Procedure
All crankpins were ground to 0.50 mm undersize. The grinding process restored the proper journal geometry, surface finish, and fillet radii, ensuring smooth lateral movement of the connecting rods.
Final Results
Post-machining inspection confirmed the following measurements:
- Conical deviation: 0.00 mm
- Flatness: 0.00 mm
- Surface roughness (Ra): 0.11 – 0.28 μm
- Hardness range: 240 – 290 HB across the crankpins
Conclusion
The crankshaft journals were successfully restored within tight tolerances. The achieved geometry and surface quality ensure proper oil film formation and support stable and reliable engine operation, provided that bearing condition, connecting rod geometry, and operational clearances are maintained according to manufacturer specifications.
