hole they are never retrieved or reuseable referring to fig1 and 2 it can be seen that the head end portion 12 of the subject bit 10 is somewhat larger although not substantially larger in diameter than the largest diameter of the body portion 22 this relatively small difference in the case of the present bit is an important advantage over known drill bits that have cylindrical body portions used for the same or similar purposes this difference in body to head diameter in the present bit can be from no difference at all to a relatively slight difference this is possible with the present bit because of the passages formed in the bore by the flats 26 combined with the pulverizing action produced by the body teeth portions 32 the flats 26 also provide means to concentrate the flow of fluid and residue which is a further advantage and the flats operate with the teeth 32 during rotation of the bit to swirl the fluid and residue and increase the pulverizing action a condition that is clearly not true of bits that have cylindrical body portions another very useful feature of the present bit construction is obtained by the provision of rearwardly projecting body portions 34.