Before starting to drill with any particular rig, thoroughly read and understand the manufacturer’s manual for the machine. Make sure the drilling table, or platform, is clean, dry as possible, and free of loose objects. Doing so will help prevent personal injury and loss of tools down the drill hole. For safety, ensure that the  sheave  guards  remain  in  place  over  moving  gears and chain drives while the rig is operating. Drillers learn from experience why a well is dug in a certain way and can visualize conditions at the bottom of the hole. No set rules have been established to follow for adjusting speeds of rotation and bit pressures. In general, you proceed to set up the rig as follows: Move the rig into position on the selected site. Use the hydraulic outriggers to level the rig and take the weight of the rig off the axles. Next, raise the mast and lock it in place. Now check to see that the rig is slightly higher in  the  rear  to  allow  for  settling  during  the  drilling operation. For kelly-drive  rotary  drilling  you  continue  by doing  the  following: 1. Run the kelly through the turntable and thread the pilot bit to the kelly. 2. Place the turntable transmission in the proper gear for the soil formation being drilled. 3. Engage the turntable clutch and release the kelly brake slowly to lower the bit into the ground. 4. Engage the mud pump and lower the kelly after the bit has spudded into a depth of 6 to 12 inches. 5. Proceed to drill to the depth of the kelly. Raise the drill bit 6 to 10 inches, circulate to bring all cuttings to the surface, than shut off the mud pump and stop the turntable. 6. Next, raise the kelly until the pilot bit reaches the surface. Remove the pilot bit and lift the kelly clear of the  turntable. 7. Move the turntable from its position over the hole. Raise, then lower, a surface casing into the hole, using the hoisting drum. The surfacing casing keeps the well from caving-in from the surface. 8. Once again, position the turntable over the hole. 9. Next raise, then lower, a length of drill pipe into the hole through the turntable, using the hoisting line. The slips will hold the drill pipe in place in the turntable. 10. Follow up by lowering the kelly and attaching it to the drill pipe. To keep these parts from seizing, apply dope on the kelly coupling. 11.  Using  the  kelly  drum,  raise  the  kelly  and attached drill pipe just enough to enable the slips to be removed. 12.  Lower  the  kelly  and  drill  pipe  so  the  kelly bushing nut slips into the turntable. 13. Engage the turntable and start the mud pump. In doing so, you lower the kelly to drill again. 14. The slips hold the drill pipe in place until the breakout  thongs  are  attached  to  the  kelly.  Rotate  the turntable slowly until the kelly is unscrewed from the drill  pipe. 15. Raise the kelly far enough so another length of drill pipe can be added to the pipe remaining in the hole. Reconnect the kelly and lower into the turntable. 16. Start drilling again until you reach the end of the kelly. Keep repeating this procedure until you have drilled to the desired depth. You are now ready to complete the drilling  operation.  Proceed  to  remove  the  drill  pipe  by pulling it out with the hoisting line. Finally, lower the casing with the screen to the desired depth. If you must change bits before the desired depth is reached, disconnect the kelly and attach the hoisting line to the drill pipe. Pull the drill pipe a length at a time, placing the bottom ends on a board to help keep them clean. Top-Head Drive Rotary Well Drilling Rig The top-head  drive  rotary  well  drilling  rig  is a special  top-head  drive  ISO/airtransportable  water well-drilling   rig   (ITWD)   (fig.   9-12)   that   the development and production effort was conducted or controlled by NAVFAC towards providing the NCF with the capability for rapid water well drilling in a variety  of  environments. The  self-propelled  ITWD  design  has  a  lightweight derrick  a  telescoping  mast,  and  a  top-head  rotary  drive actuated  by  hydraulic  cylinders  able  to  accommodate 20-foot-long sections of drill pipe and well casings. When the derrick is lowered for transport, the entire rig weighs 23,000 pounds and is capable of fitting inside a standard cargo container without disassembly and is air transportable on board a C-130 aircraft. The ITWD is capable  of  rotary   drilling   12  1/4-inch  holes  to 1,250-foot  depths  and  down-hole-drilling   (DHD) hammer  (percussion)  drilling,  6-inch   holes   to 1,500-foot depths. The ITWD will travel at a top speed 9-10