TM 9-2320-209-10-1 h. Boring in Various Soils. CAUTION Use care so that auger and boring machine are not damaged when boring in soil containing loose rock. Take loose rocks larger than 10-inches in diameter out by hand or other means. 1. To bore in disintegrated shale or similar soil, step on clutch pedal (1). Set FRONT TRANSMISSION gearshift lever (2) in position 1 and let clutch pedal (1) up. 2. Set hand THROTTLE (3) to let engine run at 1800 rpm, as shown on tachometer (4). Auger will turn at about 25 rpm. (Refer to tables 4-3 and 4-4.) GO TO FRAME 2 4-347