Sandvik 900 294 16 Bit

The bit, part 900 294 16, is the part of the drill string that actually meets the rock, and its carbide buttons wear in a way that tells you how the drilling has been going. Buttons that are evenly flattened point to normal abrasion, while chipped or snapped buttons point to impact damage from running too hard, and a bit worn on the outer ring of buttons first has lost gauge and will drill a hole that narrows with depth.

Regrinding the buttons before they are worn flat restores the cutting shape and the penetration rate, but a bit left too long loses its gauge and then cannot be brought back economically. The flushing holes must stay clear, since a blocked hole stops the cuttings leaving the bottom of the hole and the bit regrinds the same rock again, overheating itself. Confirm the part number against the size, thread and button layout of the one being replaced, as bits of a similar look are made for different holes and rods. Stalroc quotes this Sandvik reference by part number and exports worldwide to mining, quarrying, and drilling contractors.