Hertel SDD43274885 Step Drill Bit 14 Sizes 4-30mm Hss

Product Description

The HERTEL SDD43274885 is a high-speed steel step drill bit engineered for drilling multiple hole diameters in a single tool. It covers 14 hole sizes ranging from 4 mm to 30 mm in diameter, with a 5 mm step length between each size increment. The round shank with three flats measures 10 mm in diameter, providing a secure grip in compatible chucks to resist rotation under torque. The bright, uncoated finish is standard for general-purpose HSS step bits used in sheet metal, thin-gauge steel, plastic, and similar materials. Installers in HVAC, electrical, and plumbing trades rely on step bits to punch clean, sized knockouts without a separate punch set.

This bit is suited for use in residential and light commercial applications where a technician needs to drill or enlarge multiple hole sizes in thin-wall material. Typical scenarios include punching wire or conduit knockouts in electrical panels and enclosures, sizing holes in HVAC sheet metal ductwork and equipment panels, and boring through plastic junction boxes or fittings. The 4 mm to 30 mm range covers a broad spread of common knockout sizes in a single bit, reducing the need to swap tools mid-job.

Key Features

• 14 discrete hole sizes from 4 mm minimum to 30 mm maximum diameter
• 5 mm step length between each size increment for controlled, incremental drilling
• High-speed steel construction provides durability across thin-gauge ferrous and non-ferrous materials
• Round shank with 3 flats (10 mm diameter) resists bit slippage in drill chuck
• Bright uncoated finish for general-purpose use in sheet metal, plastic, and similar substrates

Compatibility

Designed for use in standard drill chucks accepting a 10 mm round shank with flats. Suitable for general trade use in sheet metal fabrication, electrical panel work, and HVAC equipment panels requiring hole sizes between 4 mm and 30 mm.

Installation Notes

Step drill bits of this type are typically used by electricians, HVAC technicians, and plumbers working with thin-wall materials. Secure the workpiece before drilling and use appropriate eye protection and gloves when working with metal swarf. Apply consistent, moderate feed pressure to allow the steps to cut cleanly without excessive heat buildup in the uncoated HSS blank. De-energize any panel or equipment before drilling into live enclosures, in accordance with applicable NEC lockout/tagout requirements.