The 16mm Rosehead Countersink Bit HSS is a rotary cutting tool designed to form a clean, 90° conical recess (countersink) for seating countersunk screw heads and to deburr holes in metal, timber and plastics. Its primary use is in preparing holes for flush fastener installation and removing burrs after drilling to ensure correct screw seating and a neat finish.

Manufactured from M2 high speed steel (HSS) with a precision ground cutting face, this countersink retains hardness at typical cutting temperatures and gives an extended tool life compared with carbon-steel alternatives. The bit produces a 90° included angle suitable for standard countersunk screws and has a round shank compatible with standard three-jaw drill chucks and most power drills. The cutting geometry follows established DIN/ISO tooling profiles for countersinks and is appropriate for applications conforming to BS fastener seating practices.

This rosehead style countersink offers multiple cutting lips for smooth material removal and reduced chatter, making it effective on mild steel, aluminium, brass, castings and a wide range of timbers and synthetics. It is commonly used in woodworking and joinery for fitting countersunk screws, in metal fabrication and maintenance for deburring and preparing fixings, and in general workshop and site work where a reliable flush finish is required.

Key benefits include the wear resistance and edge stability of M2 HSS, which maintains cutting performance longer than tool steel bits; compatibility with standard drill chucks; and the precision 90° geometry that ensures correct seating of BS/ISO countersunk fasteners. The ground finish sheds swarf cleanly for improved surface finish and repeatable results across batches of components.

Duchy Fasteners stocks a complete range of rosehead countersinks in multiple diameters and pack options to suit trade and workshop needs. The 16mm HSS rosehead is available as single items and in multi-pack formats; please contact Duchy Fasteners for current stock sizes and pack quantities.