churn drill
churn drill
Portable drilling equipment, usually mounted on four wheels and driven by steam-, diesel-, electric-, or gasoline-powered engines or motors. The drilling is performed by a heavy string of tools tipped with a blunt-edge chisel bit suspended from a flexible manila or steel cable, to which a reciprocating motion is imparted by its suspension from an oscillating beam or sheave, causing the bit to be raised and dropped, thus striking successive blows by means of which the rock is chipped and pulverized and the borehole deepened; also, the act or process of drilling a hole with a churn drill. Also called American system drill; blasthole drill; cable drill; cable-system drill; churn-drill rig; rope-system drill; shothole drill; spudder; spud drill; wet drill.
A long iron bar with a cutting end of steel, used in quarrying, and worked by raising and letting it fall. When worked by blows of a hammer or sledge, it is called a jumper or jump drill.