Rigid, robust and simple design Hardened and ground – long lasting precision Five sizes for power drives from 3 – 28 kW Accuracy after change guaranteed to be within 0.01mm Square base Böni Quick-change Tool Holders have been made for more than 70 years Constructional characteristics of the Böni Quick-change Tool Holders are its extremely solid, stable and of simple design. The tool post is made of forged steel which has been carefully case hardened. Its square shape is best suited to the bearing surface of the cross slide. A square bearing surface is very important because it creates a positive connection with the machine up to a point just below the tool cutting edge. This means there is less strain an the cross slide of a lathe than from a relatively small bearing surface at the centre of the cross slide. A strong bolt prevents the tool post from turning, but it can be released at any time if it has to be moved to another position. Precision-ground veeways on both, tool post and exchange holders interact with hardened and ground eccentric shafts, which are seated in precision-honed bores, to connect these Parts rigidly, allowing heavy and interrupted cuts to be made without difficulty. Since the veeways suffer virtually no wear there's no limit to accuracy or rigidity.