rid a lubricant with a viscosity of 1200 seconds saybolt universal at 100 u00b0 f of substantially all air and gas the lubricating passages and spaces of the drill bit are also evacuated of air and gas but not necessarily simultaneously with the degassing of the lubricant each nipple 139 141 143 is connected to an enlarged region or recess 29 of each of the three filler holes 27 of a three cone bit the o rings 145 forming a fluid tight seal the previously described passages and spaces are then evacuated by opening valves v 6 v 7 v 8 to the vacuum pump p 1 valve v 5 may remain open or may be closed after both the lubricant and the passages and spaces are substantially free of air and gas valve v 1 is closed and the system checked for leaks by observing gage 107 if no gage variation is detected valve v 4 is closed to block the lubricant valve v 5 opened and lubricant forced into the passages and spaces of the drill bit by turning screw handle 125 to move piston 117 inwardly the desired pressure which for the disclosed viscosity is about 500 psi pounds per square inch will be indicated by gage 113 after filling valve v 5 is closed the nipples 139 141 143 are removed from the bit.