Premium HSS Cobalt Spiral Step Drill Bit Set 3PCS

Key features

A versatile three-piece step drill bit set designed for workshop and DIY use, combining M35 HSS with 5% cobalt and a TiAlN coating for longer life and consistent cutting. These spiral cone bits tackle sheet metal, aluminium, stainless steel up to around 1mm, wood and plastic, and they come in a storage box for tidy organisation. The hex shank reduces slipping in the chuck and suits bench drills, handheld drills and press setups.

Specifications

• Name: 3PCS Premium HSS & Cobalt Spiral Step Drill Bit Sets (1/4"-7/8")
• Material: M35 high speed steel, 5% cobalt
• Coating: TiAlN Titanium Aluminium Nitride
• Type: Spiral step drill bits
• Size: 1/4" to 7/8" range across three bits

Benefits

These step bits save time by cutting multiple hole diameters with a single bit and by deburring as they drill. The TiAlN coating helps retain edge hardness under heat, and the spiral flute promotes cleaner chip evacuation. Expect improved durability on tougher metals compared with uncoated HSS, according to the manufacturer. A small caveat is that for thicker stainless steel you may need specialist bits or lower speed and cutting fluid to avoid overheating.

How to use it

Start at low speed and apply cutting oil or water spray when drilling metal, this helps prevent overheating and preserves the coating. Gradually step up the diameter by following the marked steps on each bit, and clamp work securely to avoid movement. It’s a good match for general repair, panel work and sample holes when you need various diameters without changing tools.

What’s included

Three spiral step drill bits in a storage box, covering the following step ranges across the set: 1/4" to 1/2" on smaller bits and up to 7/8" on the largest bit. The hex shank fits standard chucks to reduce slipping and speed changes during use.