Step Drill Bit GRAPHITE 57H739 cylindrical steps 4–22 mm set (4,6,8,10,12,14,16,18,20,22 mm)

GRAPHITE step drill bit model 57H739 with a cylindrical stepped profile covers hole diameters from 4 mm to 22 mm in preset increments: 4, 6, 8, 10, 12, 14, 16, 18, 20 and 22 mm. The tool is intended for drilling and enlarging holes in sheet metal, plastic and other thin materials. Its stepped geometry allows sequential cutting of multiple diameters without changing tools, suitable for use in handheld drills and drill presses when a range of hole sizes is required.

Advantages

The stepped design reduces the need for multiple drill bits, saving time during size changes and simplifying workflow. Cylindrical step profiles provide stable centring and smoother cutting through thin materials. The single-piece construction minimizes wobble and improves concentricity compared with stacked or multi-piece alternatives. Compatible with common drill chucks, the bit supports fast switching between sizes and is practical for both on-site and workshop use.

Suitable for

• Drilling and enlarging holes in sheet metal
• Cutting holes in plastic panels and thin composite materials
• On-site maintenance and installations requiring multiple hole sizes
• General metalworking and electrical installations

Key specifications

• Stepped diameter range: 4–22 mm with incremental steps at 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 mm
• Stepped cylindrical profile for sequential drilling
• Intended materials: sheet metal, plastic and thin material types
• Compatible with standard drill chucks (hand drills and drill presses)
• Single-piece construction for improved concentricity and reduced wobble

How to use

Secure the step drill bit in the drill chuck and ensure it is tightened correctly. Mark the centre of the hole, align the drill perpendicular to the workpiece and start at a low speed to establish a pilot. Progressively advance to the required step to obtain the desired diameter, applying consistent feed pressure and cutting fluid when drilling metal to improve chip evacuation and tool life. Retract occasionally to clear chips and prevent overheating. After use, clean the bit of debris and store it dry to avoid corrosion.

Usage recommendations

For best performance on metal, use cutting oil and moderate speeds; reduce speed and increase feed for thicker or harder materials. When drilling thin sheets, clamp the workpiece to prevent deformation and burr formation. Replace the bit if wear or pronounced dulling occurs to maintain hole quality.