SDS drill: what it does and when to reach for it

Learn what an SDS drill does, when to use it, and how to drill safely into masonry.

SD-01Understand what makes an SDS drill differentAn SDS drill uses a hammer action as well as spinning, so it punches and rotates at the same time. Ordinary drills just spin, which is why they struggle in brick, block or concrete. SDS stands for the type of chuck (bit-holder) that lets the bit slide slightly and take the hammer blows without the bit falling out.

SD-02Know when to reach for itUse an SDS drill for masonry: brick, blockwork, concrete and stone. For wood or metal, use an ordinary drill or combi drill instead - the hammer action is too aggressive and will chew up the hole. If you're not sure what's behind a wall, treat it as masonry and use the SDS.

SD-03Fit the bit correctlyPull back the collar (the ring) at the front of the chuck, push the bit in as far as it will go, then let the collar go. Give the bit a gentle tug - it should stay in but wiggle slightly back and forth, which is normal for SDS. If it falls straight out, it's not seated properly, so remove it and try again.

1 each · SDS masonry drill bit

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SD-04Set the right modeMost SDS drills have a dial with symbols: a drill bit alone (rotation only), a drill bit with a hammer (rotation plus hammer, for masonry), and sometimes a hammer alone (chisel mode, no rotation, for chipping tile or plaster). For drilling into brick or concrete, select rotation plus hammer.

SD-05Check for cables and pipes before you drillBefore drilling into any wall, floor or ceiling, use a cable and pipe detector to scan the area. But treat the detector as a warning system, not a guarantee - it can miss cables that are deep, run in metal conduit, sit behind metal-backed plasterboard, or simply run somewhere unexpected. Older or DIY wiring often ignores the normal 'safe zones' around sockets and switches entirely, so expect something to be there and prove otherwise, rather than trusting a clear scan alone. If you have any doubt, isolate the circuit at the consumer unit before drilling, and turn off the water at the stopcock before cutting into anything that could carry a pipe.

SD-06Drill with a light touch and listen to the toolMark your point, hold the drill square to the wall, and let the hammer action do the work - you only need gentle forward pressure, not brute force. You'll feel a steady juddering vibration and hear a rhythmic rattling sound; if the drill is bogging down or stalling, ease off rather than pushing harder. Pull the bit out every few seconds to clear dust, especially in deep holes, so it doesn't clog and overheat.

SD-07Check you've drilled it rightA good hole is round, straight, and the same width all the way in - not tapered or ragged at the edges. Fine grey dust coming out steadily is a good sign for brick or block; if you hit something noticeably softer or harder halfway through, stop and check what you've hit before continuing. The bit should slide in and out of the finished hole freely, without grabbing.

SD-08Clean up after useWipe dust off the bit and out of the chuck before storing, so grit doesn't wear the mechanism. A dirty chuck is the most common reason bits stop seating properly next time you use the drill.

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