Stabilizer for an in situ column drilling apparatus

A stabilizer for preventing changes in the drilling direction of an in situ column drilling system having a shaft and an auger bit, said stabilizer comprising:

• a first and a second set of mounting arms, each of said mounting arms adapted for rotatable coupling to a shaft of the drilling system, said first and second set of mounting arms coupled to the shaft spaced apart along a longitudinal axis of the shaft proximate the auger bit, the longitudinal axis extending in the drilling direction;
• first and second stabilizing members for preventing movement of the auger bit in a first direction, the first stabilizing member attached to ends of the first and second set of mounting arms, the first stabilizing member extending parallel to and about the longitudinal axis of the shaft between the ends of the first and second set of mounting arms, and the second stabilizing member attached to ends of the first and second set of mounting arms distal the first stabilizing member, the second stabilizing member extending parallel to and about the longitudinal axis of the shaft between the ends of the first and second set of mounting arms, the first and second stabilizing members having a plate shape, the first and second stabilizing members having a curved, semi-cylindrical shape and being curved about the longitudinal axis of the shaft for a close fit with a wall of the column;
• and
• first and second stabilizing tabs for preventing movement of the auger bit in a second direction, said first and second stabilizing tabs mounted to the first and second stabilizing members, respectively, said first and second stabilizing tabs mounted parallel to the longitudinal axis of the shaft and extending radially outward from the respective stabilizing members.