EZARC 3-Piece M35 Cobalt Step Drill Bit Set / Unibit Set – Metric 4–32mm, AlTiN Coated, Spiral Flute, 1/4" Hex Shank, For Metal & Stainless Steel

3 Bits. Metric 4–32mm. M35 Cobalt. AlTiN Coated. Every Hole Size Covered.

Sheet metal, stainless steel, aluminium, brass, copper, cast iron — the EZARC 3-Piece M35 Cobalt Step Drill Bit Set (also known as a unibit or cone drill bit set) covers the full metric range from 4mm to 32mm across three precision-engineered bits. No more swapping between multiple drill bits — each step cuts a clean, precise hole in a single pass. M35 cobalt high-speed steel delivers superior hardness and toughness over standard HSS, and the AlTiN coating (89 HRC) withstands temperatures up to 900°C for all-day cutting performance. The triple-flute C-profile cutting edge gives 2× the cutting speed of standard step drills with enhanced stability and reduced deviation. All three bits feature a 1/4" hex shank for quick-change compatibility.

Key Features

• 3-Piece Metric Set — 4–32mm Range — full coverage across the most common metric hole sizes
• M35 Cobalt HSS — superior hardness, toughness and bending strength vs standard HSS; ideal for harder materials
• AlTiN Coating (89 HRC) — aluminium titanium nitride; resists heat up to 900°C, wear and corrosion; outlasts black oxide coatings
• Triple-Flute Spiral Design — enhanced stability; reduces deviation during cutting
• C-Profile Cutting Edge — smoother cutting; 2× faster than standard step drills
• 1/4" Hex Shank — fits standard drill chucks and quick-release hex chuck systems

Compatible Materials

• Mild steel and medium hardness steel (plate up to 3mm)
• Stainless steel (plate up to 1mm)
• Aluminium, brass, copper and cast iron
• Galvanised pipe and low-carbon steel
• Plastic

Usage Tips

• Use low speed and light pressure until reaching the desired depth
• Apply cutting oil or water-soluble lubricant to reduce friction, heat and debris
• Start-up speed may be slower due to the larger cutting angle — this is normal