Mechanical plug drill

Abstract From the Canadian patent

A device for removing plugs from plugged tubes in a steam generator including a frame having a substantially flat plate, with a hollow drill bit mounted thereon and movable generally perpendicularly with respect thereto from a storage position to an operating position. An elongated retaining pin extends through the hollow drill bit and therebeyond having threads on one end thereof for attachment to the plug to be drilled. Actuating means moves the drill bit between the storage position thereof and the operating position thereof, motor means is mounted on the frame for rotating the drill bit. An air-water mixture is introduced near where the drill bit meets the plug to be drilled, the water …