TABLE OF CONTENTS Material choice for countersinks is critical for economical tool life. The most common materials used are listed below and the effectiveness of any of them can be found in general by reading the literature for drill materials. In this instance drilling and countersinking face the same basic cutting temperature issues, but countersinking is more forgiving for most applications since it cuts for a much shorter distance.
Common countersink tool materials
High speed steel (HSS)
Cobalt high speed steel (cobalt HSS)
Solid tungsten carbide
Micrograin tungsten carbide
Surface-treated carbide
Carbide-tipped tools
Titanium nitride (TIN) coated tungsten carbide
T-15 titanium nitride (T-15 TIN) coated carbide
Titanium carbonitride (TiCN)
Electroplated diamond
Polycrystalline diamond (PCD) coated steel
Countersink tools that use inserts are discussed late in this chapter. Carbide tipped, as opposed to carbide insert, implies that the tip is permanently mounted on the tool. All the materials listed above are found on non-insert tools and most can also be found on throwaway inserts.
