SDS-PLUS Round Shank Electric Hammer Drill Bits (25x350)

The problem is breakout. As a large bit reaches the far face of a wall, there is very little material left in front of it, and the hammer action punches that last thin layer out rather than cutting it. What falls off the other side is not a neat circle: it is a ragged crater of render and block, often much wider than the hole, and on a finished wall in somebody's house that is a repair job and an awkward conversation.

There are two ways round it. The better one is to drill from both sides. Mark the position accurately, drill from the first face until the tip just breaks through, then go to the other side, find the small pilot hole the tip made, and drill back to meet yourself. Both faces are then cut rather than punched, and both are clean. The second method, when you can only reach one side, is to ease right off the feed pressure as you sense the bit approaching the far face, so the last few millimetres are cut gently rather than driven through.

Accuracy matters for the first method, so take a moment over the marking and keep the drill square. A hole started at an angle in a thick wall can emerge a surprising distance from where you intended.

Twenty five millimetre penetrations take waste and condensate pipework, refrigerant line sets, larger cable bundles and conduit.

SDS-PLUS shank, hammer grade carbide, dust clearing flute design.

Buyers are plumbers, air conditioning and refrigeration installers, electricians, mechanical services contractors and maintenance departments.

Message us on 94 77 111 8880 for bits, sleeves and sealant together, delivered anywhere in the island.