Bihui Core Bit Set of 6, 6 to 70 mm

The BIHUI diamond core bit set includes 6 core bits of 6, 8, 20, 35, 50, 70 mm diameter. The core bits have a diamond layer made by the newest method: the diamonds are bonded to the bit by vacuum brazing. This method lets you drill holes very fast and with no effort, even in hard porcelain stoneware. Drilling is best done at medium revs on an angle grinder. Before drilling it is worth putting a wet blotter inside the core bit, cut to size beforehand. Start the hole and drill it while constantly changing the angle of tilt from side to side. Do not press hard against the face of the tile. Cooling it down suddenly is absolutely out. Do not drill a run of holes one after another, let the core bit rest. The gem of the set is a good case for keeping the bits in. A core bit of medium diameter will do 40 – 50 holes on average in 10 mm porcelain stoneware. No warranty