Dry Diamond Core Bit 127 x 150mm. Faithfull Dry Diamond Core Bits combine a professional quality 1/2in BSP threaded core with premium 8mm fluted turbo cut diamond segments. They are manufactured to offer exceptional wear and speed of cut. The V-groove segments assist in clearing debris when in use. Suitable for rotary use ONLY! Must not be used on percussion/hammer mode. We have over 40 years experience supplying spares to Construction, Plant Hire and Groundcare and are main dealers for many construction and groundcare brands.