RUKO FLS-DIN373-HSS-TiN-M-4x Countersink, HSS, TiN Coated, 90°, M4

For machinists and metalworkers preparing precise countersunk holes for M4 flat-head screws in steel, cast iron, non-ferrous metals, and light alloys, this RUKO countersink delivers clean, chatter-free results. The solid pilot guides the tool accurately, while the three cutting edges and TiN coating ensure smooth finishes and extended tool life.

Key specifications

• Tool type: Countersink
• Standard: DIN 373
• Material: High-Speed Steel (HSS)
• Coating: Titanium Nitride (TiN)
• Designed for screw size: M4
• Pilot diameter (d1): 4.5 mm
• Countersink diameter (d2): 8.0 mm
• Shank diameter (d3): 8.0 mm
• Overall length (l1): 63 mm
• Flute length (l2): 18 mm
• Cutting angle: 90°
• Number of cutting edges: 3
• Shank type: Parallel shank
• Application material compatibility: Steel, cast iron, non-ferrous metals, light alloys
• Recommended screw head standards: DIN 963, DIN 964, DIN 966, DIN 7991
• Tool geometry: Solid pilot
• Manufacturing process: Ground

Why choose it

The TiN coating reduces friction and heat buildup, improving performance and tool life compared to uncoated HSS. The solid pilot ensures accurate centering, preventing wandering and producing consistent countersinks.

Ideal use cases

• Countersinking holes for M4 flat-head screws in steel components
• Deburring and chamfering edges in cast iron or non-ferrous metals
• Preparing holes for DIN-standard screws in light alloy fabrications

Good to know

This countersink is manufactured to DIN 373 specifications and is suitable for use with a variety of materials. The parallel shank fits standard drill chucks and collets.