RUKO FLS-DIN373-HSS-TiN-M-4x Countersink M4 TiN-Coated HSS

The FLS-DIN373-HSS-TiN-M-4x countersink from RUKO GMBH is a precision tool for spot facing and countersinking holes for M4 flat-head screws. Its TiN coating reduces friction and extends tool life when working in steel, cast iron, non-ferrous metals and plastics.

Highlights

• Three-flute design for smooth, chatter-free countersinking
• TiN coating for improved wear resistance
• Cylindrical shank with h8 tolerance fits standard drill chucks
• Ground profile for accurate cutting geometry

In daily use

This countersink is intended for creating clean, consistent seats for M4 screw heads. The pilot diameter of 4.5 mm guides the tool in pre-drilled holes, while the 8 mm cutting diameter produces the correct countersink profile. The right-hand cut and three flutes ensure efficient chip removal.

Full specifications

• Standard: DIN 373
• Material: HSS (High-Speed Steel)
• Coating: TiN (Titanium Nitride)
• Designed for screw size: M4
• Pilot diameter (d1): 4.5 mm
• Cutting diameter (d2): 8 mm
• Shank diameter (d3): 6 mm
• Overall length (l1): 63 mm
• Pilot length (l2): 10 mm
• Number of flutes: 3
• Cutting direction: Right-hand cut
• Shank type: Cylindrical shank
• Shank tolerance: h8
• Manufacturing process: Ground profile

Final note

A reliable countersink for M4 screw applications, built to DIN 373 with a TiN coating for longer service life.