The utility model provides a tribrachia drill jumbo beats fixing device who establishes feet -lock bolt, includes backup pad (1) of square structure, and backup pad (1) divide into left side subtotalright side part, and the left side part welding of backup pad (1) has jack (2), and round hole (3) that are greater than drill size are seted up to the right side part of backup pad (1), and the leftside of backup pad (1) part width = steelframe (1) flange width 2 steelframe (1) web thickness, the right side of backup pad (1) part width = diameter of bit +3cm, jack (2) welding is at backup pad (1) the left side sub -center of portion, round hole (3) set up at the right side sub -center of portion. The problem of interval, the angle of tribrachia drill jumbo manual operation drilling heavy handled is solved.