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The concrete core cutter is a diamond-tipped drill used in high-rise construction to bore holes up to 8-in diameter through floors. One model requires an electrical power supply and is rather bulky, but it's easier to use when drilling overhead into the slab above to apply water from the floor below...

The concrete core cutter is a diamond-tipped drill used in high-rise construction to bore holes up to 8-in diameter through floors. One model requires an electrical power supply and is rather bulky, but it's easier to use when drilling overhead into the slab above to apply water from the floor below (Fig. 18-35). A smaller, lighter, gasoline-driven model is also available (Fig. 18-36). The diameter of its cores is limited to 4-in. holes, which are too small to pass a 2½-in. This core drill is set up to drill through from the floor below the fire. A stream may then be directed upward through the hole to cool the fire area. The actual drilling is a relatively fast process: A 6-in. reinforced concrete floor can be pierced in about 5 minutes. The concrete cutting chain saw is another tool.