Chicago-Latrobe 55447 118 Degree 47/64 in Silver & Deming Drill

Chicago-Latrobe 55447 47/64 in Drill Bit

The Chicago-Latrobe 55447 is a silver and deming drill bit sized at 47/64 in. It features a 118 degree point angle and a reduced shank for use in chucks that cannot accommodate a full-diameter shank. The bit is made from high speed steel with a black oxide finish for general-purpose drilling. It suits machinists and maintenance technicians who need a large-diameter hole in a single pass.

118 Degree Point and Reduced Shank Limits

The 118 degree point angle is a general-purpose geometry that centres easily but generates more thrust than a split-point design. The reduced 1/2 in shank fits standard drill chucks yet limits the maximum torque the bit can transmit without slipping. High speed steel loses hardness faster than cobalt or carbide when drilling hardened steels or high-temperature alloys. The black oxide finish aids chip flow but does not add wear resistance in abrasive materials.

High Speed Steel Construction and Black Oxide Finish

The high speed steel body resists softening during intermittent cuts and can be resharpened multiple times on a bench grinder. Black oxide reduces galling and helps coolant cling to the flutes during deep holes. The reduced shank transitions abruptly from the flute diameter, so the bit should be fully seated and the workpiece clamped rigidly to prevent deflection. This bit is not for buyers who need a full-diameter shank for maximum rigidity or a split point for self-centring in hard metals.