Bihui Core Bit Set of 6, 25 to 68 mm

The BIHUI diamond core bit set contains 6 bits, 25, 35, 40, 45, 50, 68 mm in diameter. The bits carry a diamond layer made by the newest method: the diamonds are bonded to the bit by vacuum brazing. That method lets you drill holes very quickly and without effort, even in hard porcelain stoneware. Drill at medium angle grinder speed. Before drilling, put a wet blotting pad inside the bit, cut to fit the bit beforehand. Start the hole and drill it while constantly rocking the bit from side to side. Do not lean hard on the tile surface. Under no circumstances cool it down suddenly. Do not drill a run of holes back to back, let the bit rest. The nice touch in this set is the decent case the bits are stored in. A mid-size bit should do 40 – 50 holes in 10 mm porcelain stoneware on average. No warranty