20mm Drill Bits

Whether you are installing thick pipes and cables, sinking heavy-duty anchor bolts, or working with dense metal components, our selection of 20mm drill bits ensures you have the right tool to achieve professional results. Designed to bore large, precise holes quickly and efficiently, these robust bits are engineered to handle high torque and resist wear during intensive use. Keeping a dedicated 20mm bit in your kit eliminates the need for frustrating re-drilling and helps you maintain accuracy on site.

We offer a variety of specific bit profiles to match your project needs. Choose from highly durable SDS plus and SDS max masonry bits to power through tough concrete and blockwork, or select extreme tri-flute and auger wood bits for rapid, clean drilling in timber joists. For metalwork, we stock reduced-shank HSS bits that fit standard chucks, as well as diamond tile hole saws and step bits for versatile applications. Rely on trade-trusted brands like Bosch, Milwaukee, DeWalt, and Toolpak for consistent performance.

Frequently Asked Questions | FAQs

What is a 20mm auger bit used for?

A 20mm auger wood drill bit is designed for drilling deep, clean, and accurate holes into thick timber, such as joists and beams. They feature a threaded tip that pulls the bit through the wood and a deep spiral flute that efficiently clears away the large volume of sawdust created, preventing the bit from jamming.

Can I fit a 20mm drill bit into a standard combi drill?

Most standard combi drills and drill drivers have a maximum chuck capacity of 13mm. Therefore, a standard 20mm straight-shank drill bit will not fit. To drill a 20mm hole with a standard chuck, you must use a "reduced-shank" bit (often called a blacksmith drill bit), which features a stepped-down base designed specifically to fit 10mm or 13mm chucks.

What is a 20mm step drill bit?

A step drill bit (or cone drill bit) is a single, cone-shaped bit with multiple stepped cutting edges of increasing diameters. A 4-20mm step bit, for example, allows you to drill holes from 4mm up to 20mm in sheet metal, plastic, and other thin materials without having to constantly change bits. They are excellent for gradually enlarging existing holes.