TM 9-2320-209-34-2-2 e. Replacement. 1. Slide derrick sheave assembly (1) into derrick assembly (2). 2. Tighten two screws (3) against groove in shaft of support block (4). 3. Put a coat of grease on derrick assembly (2) in derrick tube base (5). 4. Slide derrick assembly (2) over rack bar (6). Do not push it into derrick tube base (5). 5. Turn derrick assembly (2) so that boring machine operator will be able to see sighting holes (7) when derrick is in vertical position. 6. Push derrick assembly (2) into derrick tube base (5) as far as it will go. GO TO FRAME 2 17-713