8 1/2" roller bits used on 1800mm core barrel drilling bucket. 1. metal sealed bearing 2. working time: about100 hours 3. IADC:637 4. suitable to hard ...
8 1/2" roller bits used on 1800mm core barrel drilling bucket. 1. metal sealed bearing 2. working time: about100 hours 3. IADC:637 4. suitable to hard ...