Flat Bits

Flat wood bits, also known as spade bits, are flat-bladed boring bits for drilling large holes in wood quickly. This guide explains what they are for and how to choose one.

What they are for — A flat bit has a central point that locates the hole and a flat blade that scoops out the wood as it turns. This makes it the fast way to bore large-diameter holes through joists, studwork and timber, typically for running cables, pipes and conduit. They clear material quickly rather than leaving a fine finish, so they are the tool for structural and first-fix boring rather than visible joinery.

Flat bit or lip and spur — Choose a flat bit for speed and larger holes where a rough bore is fine, such as cable and pipe runs. For a clean, accurate hole in visible work, a lip and spur bit is the better choice; see our Lip & Spur Wood Drill Bits collection.

Hex shank — A hex shank grips firmly in a drill chuck and locks into an impact driver without slipping, which helps when driving a large bit through thick timber. Check your tool takes a hex shank before use.

Choosing a size — Match the bit to the hole you need, allowing clearance for the cable or pipe passing through. Order the individual sizes you use most, or a set to cover a range of holes.

For drilling metal see our HSS Drill Bits collection, and for masonry see SDS Drill Bits.

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