Drillco nitro heavy-duty construction reamer have a ferritic nitro carburizing surface treatment, which gives a hard, protective layer to the reamer. This increases hardness (Rc 75-80) without increasing brittleness, which is measurably harder than high speed steel. Body and clearance are gold and black surface treated for maximum lubricity. Construction reamer is especially adapted for heavy duty reaming as encountered in the fabrication of structural steel assemblies. They are tapered at the point to facilitate entering of holes which are out of alignment. High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance. Combination black and gold finish, for improved lubricity, corrosion resistance, and to reduce chipping or flaking. These round shank tools have flats ground onto three sides to reduce slippage of the bit when used in drill chucks. When run in a counterclockwise direction (right-hand cut) spiral fluted tools evacuate chips up and out of the cut to reduce clogging. Construction Reamer is especially adapted for heavy duty reaming as encountered in the fabrication of structural steel assemblies. They are tapered at the point to facilitate entering of holes which are out of alignment. Spiral flute designs with 3-flat straight shanks.