Abstract: A replaceable bit for cable drill tool stems including a leading longitudinal cutting rib and first and second lagging, flattened reaming portions. The cutting rib diametrically extends between and bisects the reaming portions which partially extend about the bit's circumference and progressively taper upward from a wedged horizontal cutting edge. Inwardly flared channels mating with reliefs in the drill stem are defined by the inner bit surfaces on each side of the cutting edge. Beveled top edges converge to a flat welding surface mating with a prepared drill stem. A method of replacing a worn bit on a dril bit stem with such a replaceable bit is also disclosed.