Abstract: A pilot bit is provided with an elongated body member and three blades that extend radially from and spirally along the body member. As compared to conventional two bladed pilot bits, the outer edge and leading tip of the third blade removes additional spoil which increases penetration rates. The pilot bit also includes an adapter which is inserted in an auger shaft and releasably secured thereto with a fastener, such as a bolt. The adapter includes a surface that cooperates with a key that is secured to the auger shaft to take the torque load off the bolt. In this manner, deformation of the auger shaft bolt holes and bolt fatigue is minimized.

Abstract: An excavating tooth includes an aperture for bolting the tooth to a shank plate and a lug configured to provide a friction fit in a recess formed in the shank plate. The bolt and lug combination prevent relative movement between the tooth and shank plate. In addition, tooth load is absorbed in the shank plate through the connection between the lug and shank plate, thereby reducing the stress transferred through the bolt.

Abstract: An auger is provided with a boring head having an arrangement for cutting relatively hard earth formations such as rock. First and second groups of drill bits are mounted to the boring head such that when the head is rotated, each bit in those groups cuts a different path at a different height to provide more than 100% coverage of the work surface being cut, while stabilizing the auger by distributing the down force of the auger over the entire work surface. The drill bits also are orientated to ensure bit rotation at relatively large attack angles (the angle the bit forms with the work surface therebeneath) of about 50.degree.-60.degree. to enhance auger penetration rates without detracting from the bit sharpening effect that results from proper bit rotation.

Abstract: A reversible tooth includes alternate surfaces mounting to a shank plate. The surfaces are constructed so that the attack angle of the tooth, i.e., the angle at which the tooth penetrates the earth, is changed by turning the tooth over and alternating the mounting surface secured to the shank plate.

Abstract: An auger is provided with a boring head having an arrangement for cutting relatively hard earth formations such as rock. First and second groups of drill bits are mounted to the boring head such that when the head is rotated, each bit in those groups cuts a different path at a different height to provide more than 100% coverage of the work surface being cut, while stabilizing the auger by distributing the down force of the auger over the entire work surface. The drill bits also are orientated to ensure bit rotation at relatively large attack angles (the angle the bit forms with the work surface therebeneath) of about 50.degree.-60.degree. to enhance auger penetration rates without detracting from the bit sharpening effect that results from proper bit rotation.