115mm Turbo Vacuum Brazed Diamond M14 Core Bit. Professional grade diamond core bit / hole saw. Our premium Black Diamond Series. 10mm of vacuum brazed diamond. M14 fitting for standard polishers or grinders. Ideal for both professional (stonemasons, tilers, installers etc) and DIY use. Has been extensively tested on flagstone, porcelain, granite and marble. Wet or dry use. Internal water feed (cooling wax internal on smaller sizes). Side cut and top cut outs for easy core removal. HSW Diamond Tools ensure that everything that we sell meet our highest quality expectations, we extensively test each product on a range of materials from slate, granite to quartz. Unlike other stone tool suppliers we use the tools every day while engraving Highland Slate, we can offer advice and recommendations on all our products based on experience and use.