Drill bit AWTools AW40953 Step twist drill 4–39 mm AICrN black

The AWTools AW40953 Step twist drill 4–39 mm AICrN black is a stepped drill designed to drill a range of hole sizes with a single tool. Manufactured by AWTools, this step twist drill covers diameters from 4 mm up to 39 mm in progressive steps and features an AICrN (aluminum chromium nitride) coating with a black finish for improved surface hardness and wear resistance. The tool is intended for metalworking, thin sheet materials and general workshop applications where sequential hole enlargement or deburring is required without repeatedly changing drills.

Advantages

The AICrN coating increases surface hardness and reduces friction, extending tool life when working with ferrous and non-ferrous metals. The stepped geometry enables rapid progressive drilling and consistent hole concentricity across multiple diameters, reducing setup time. The design minimizes the need for multiple drills and simplifies hole-sizing operations, while the black finish helps resist corrosion and provides visual indication of a coated cutting surface.

Suitable for

• Drilling and enlarging holes in sheet metal and thin plates
• Progressive hole sizing in workshop and maintenance tasks
• Fabrication tasks where multiple hole diameters are required
• Deburring and chamfering of drilled openings

Key specifications

• Diameter range: 4 mm to 39 mm in stepped increments
• Coating: AICrN (aluminum chromium nitride) for increased hardness and reduced friction
• Finish: black coated surface
• Type: stepped twist drill (single-piece step design)
• Intended materials: metals, thin sheets and similar workshop materials

How to use

Secure the workpiece firmly and select an appropriate drilling speed for the material being processed. Center-punch the drilling location to ensure accurate starts, then position the step drill in a suitable drill chuck. Apply steady axial pressure and begin drilling at a moderate speed; allow the stepped geometry to cut progressively through each diameter. Retract periodically to clear chips and prevent heat buildup. Use cutting fluid when working with tougher metals to improve surface finish and prolong tool life.

Usage recommendations

Use caution when drilling at larger diameters and maintain proper clamping and steady feed to avoid chatter. For best results on thicker material or hardened steel, use progressive pecking, adequate cutting fluid and ensure the drill remains sharp; replace the tool when wear affects hole quality.