SDS-PLUS Round Shank Electric Hammer Drill Bits (32x350)

The cutting end is a piece of tungsten carbide brazed onto a steel body. Carbide is extremely hard, which is what lets it work stone and concrete, and hard materials are brittle, which is what makes the tip vulnerable. So a hammer bit does not usually wear out gradually the way a twist drill does. It gets damaged.

Look at the tip in good light before a big job. Three things tell you it is finished. Chipping along the cutting edges, which means the bit is no longer cutting a full circle and will drill oversize and slow. Rounding of the sharp corners where the carbide meets the body, which is normal wear and eventually means the bit polishes rather than cuts. And any sign of a gap, a dark line or movement at the joint between the carbide and the steel, which is the braze failing. That last one matters most, because a tip that comes off inside a deep hole is a genuine problem: it jams, and getting it out of a 350mm deep hole in a wall is not a quick job.

The thing that kills the braze is heat, and the thing that causes heat is a packed hole. So the flute clearing habit is not only about drilling speed, it is what keeps the bit alive.

A bit that has been forced onto rebar deserves a particularly careful look before it is used again.

Thirty two millimetre holes take large services penetrations, sleeved pipework and ducting, and heavy through fixings.

SDS-PLUS shank, hammer grade carbide, double narrow land flute design.

Buyers are mechanical and electrical services contractors, civil trades, plumbers, industrial maintenance and hardware dealers.

Bring a worn bit in or send a photograph on 94 77 111 8880 and we will tell you honestly whether it has life left. Delivered island-wide.