Assertion: pile bore | /r/HasProperty | excavated by main bits
Facets:
value: by rotating them
type: MANNER
Source sentences:
text: Further, since the straight pile bore is excavated by the main bits by rotating them in one direction and the under-reamed bore is excavated by the slidable wing bits by rotating them in the opposite direction thereto, and since the keys and the key-ways provided between the inner pipe and the outer pipe are arranged at a skew angle, it is possible to slide the slidable wing bits downward smoothly and quickly, thus an accurately under-reamed pile bore can be excavated efficiently by a relatively simple method of excavation.