Broca helicoidal RUKO DIN 345 HSS-E Co5 33,5 mm cone Morse MK4

Machine shops and metalworking professionals drilling large-diameter holes in tough alloy steels rely on this RUKO twist drill bit. The 33.5 mm bit with Morse taper shank mounts directly into the tailstock of a lathe or the spindle of a radial drill, eliminating the need for a chuck and providing positive drive for heavy cuts.

Key specifications

• Drill diameter: 33.5 mm
• Standard: DIN 345
• Material: HSS-E Co5 (high-speed steel with 5% cobalt)
• Shank type: Morse taper MK4
• Total length: 315 mm
• Cutting length: 180 mm
• Point angle: 130°
• Surface finish: bright
• Flute type: standard spiral flute
• Direction of cut: right-hand
• Tolerance: h8
• Coolant through: no

Why choose it

The 5% cobalt alloyed HSS-E substrate withstands high cutting temperatures, retaining hardness when drilling stainless steel, cast iron, and alloyed steels. Ground from solid, the bit offers precise concentricity and a bright finish that reduces chip adhesion. The Morse taper shank ensures secure torque transmission without slippage under heavy feed pressure.

Ideal use cases

• Drilling large holes in steel plates, beams, and machine frames
• Creating bolt holes in flanges and structural components
• Enlarging existing holes in castings and weldments
• Working with non-ferrous metals and plastics when high accuracy is required

Good to know

For optimal tool life, use cutting fluid or coolant when drilling steel and stainless steel. The 130° point angle suits general-purpose metal drilling. The h8 tolerance ensures the hole diameter is within a tight range, suitable for most engineering fits.