Abstract: A universal chuck is presented which has the ability to either transmit a tensile or pulling force to the end of a piercing rod or transmit a rotational moment or force to a drill bit on a piercing machine for piercing a tap hole of a shaft furnace. The universal chuck of this invention comprises a rotary body mounted on the drive spindle of a working member slidably mounted on a piercing machine. A suitable support structure integral with the working member forms a guide cage around the rotary body. Structure for transmitting the tensile or pulling force to the end of a piercing rod and a rotational moment or force to a drill bit along with structure for adequately controlling operating and cooling fluids to a drill bit are arranged about a front cavity in the rotary body.

Abstract: A machine for boring a tap hole of a shaft furnace is presented for use in conjunction with a lost-rod process. In this process, a metal rod is driven into a botting mass, before it has completely hardened, and is removed later for opening a tap hole. Driving-in of the rod is performed with the aid of a to-and-fro movement of a clamp which can move over a mount through action of a first jack. Removal is performed with the aid of a continuous reverse movement of the clamp through the action of the first jack and of a powerful drive means, for example a second jack, driving the first jack towards the rear of the mount.