Komatsu PW160-7H Operation & Maintenance Manual page 342

INTRODUCTION OF ATTACHMENTS AND EXTENDING MACHINE SERVICE LIFE OPTIONS, ATTACHMENTS
Shape of ditch 38° bucket
How to perform excavation
Operate the boom, the arm and the bucket to make the line A of
the side-plate of the bucket vertical.
To check this position guide plate B is installed beside the bucket
pins.
Hold this plate horizontal when digging.
342 PW160-7H VEAM390100