1. The 1st process to shape on the lathe

This process shaved the journals leaving a margin of finishing.

2. The 1st process to mill the pin

This process shaved the weight part coarsely, and shaved the pins leaving a margin of finishing.

3. The process to mill the weight

In order to make it the form of a crank shaft, the outside portion of weight and superfluous portion are shaved.

4. Conditioning quality & shot peening

Internal stress is removed, the structure is stabilized and hardness is set to HRC 28-32.

5. The 2nd process to shape on the lathe

This process shaved the journals leaving a margin of polishing.

6. The 2nd process to mill the pin

This process shaved the pins leaving a margin of polishing

7. The oil hole, the key slot, and the bolt hole processing

This process made the oil holes, the key slots, the pulley bolt holes, and the flywheel bolt holes.

8. The pin and the journal polishing process

This process polished the journals and the crank pins.

9. The dynamic balance adjustment process

In order to suppress oscillating of a crank as much as possible, the balance of a crank simple substance is measured and balance processing is performed.

10. The pin and the journal wrapping process

This process is to improve the degree of true circle and surface roughness in order to gain smooth rotation and reduction of friction.

11. The surface treatment process

Surface strenth, durability of friction, and fatigue strength of the surface are improving. The surface becomes black by the surface treatment. (There is effect which helps early fitting.)

12. The final wrapping, bend correction, and inspection process

After the last wrapping, the bend which causes vibration is corrected. It is inspected after bend correction.