Abstract: There is provided a down hole hammer having a drive sub or chuck (10) having splines (11), and a drill bit (13) having a bit shank (14) having longitudinal splines (23) extending toward a bit head (15) having a bit face (16) bounded by a series of gauge row mounting portions (17), each of which has a carbide button insert (20). The bit shank splines (23) cooperate with chuck splines (11) to rotate the bit (13), the respective splines (23), (11) being proportioned to allow hammer motor exhaust air to pass down the splines. Drillings (37) are drilled from the termination of the spline milling, through to intersect with fluid passage (33) extending from sample recovery bore (22) to the bit face (16). A bore seal (32) is formed by milling a plurality of circumferential grooves (36), fed by a plurality of transverse holes (35) intersecting the air passage (33). Fluid passage (33) may be altered to fine tune the airflow to suit specific ground conditions, by effecting a change in diameter at point (38).

Abstract: A manually or mechanically/hydraulically operable tong of light weight and high load capacity by means of a multi-layer interlocking construction achieved by cutting the shapes from plate steel by known means, assembling the plate sections in suitable order, and retained with each other by cylindrical steel pins (8) forming a multi hinged tool capable of engaging the job circumference on two or more points equally via replaceable jaw dies (15) retained radially and axially.