This is the cutting bit on the end of a drilling rod. It would have been used to drill holes into rock for placing explosives, for installing steel rock anchors, etc. In hard rock the bits need to be replaced regularly. Compressed air is blown through the holes near the tip of the bit to blow rock fragments out of the drill hole. The main drilling unit would have been powered by compressed air (Pneumatic). Rotary Air Blast Drilling. This drill bit was used by workers in the SEC Vic. Kiewa Hydro Electricity Scheme. This type of bit although strong needed replacing frequently when the rock composition (type of rock) was extremely compact. The configuration of the tip bit (four star like pattern) was to provide the "teeth" to tear into the rock. This bit was manufactured in 1949 however drilling for rock cores, in the Kiewa Valley and the Victorian Alps, was carried out from the late 1920's.This particular drill bit would have been used by construction workers to drill holes into rock for either explosives or for installing steel anchor points into the rock. The use of compressed air was not only for waste extraction but also for running the main drilling unit.This four star rotary air balst (RAB) drill bit has a central "blow" hole (compressed air outlet to remove the ground rock particles through four extraction holes). There are four raised cutting/grinding lugs which allows the air compression hole(incoming) to always have a clear unblock opening. Extracted ground material is "blown" out from the drill head via the larger hole created by the steel bit.Stamped on the bottom outside shank "FAGERSTA SECO SWEDEN" and below this "102 7041 01 05 049".sec vic kiewa hydro scheme, alternate energy supplies, drilling into rocks in alpine regions