Getting a grip on precision boring

The cutting tools - for turning centres, sliding head lathes and machining centres - has been given a productivity boost with the introduction of the 3-point locating and locking toolholder line.

The QTH and QTHM toolholders have a special 3-point locate and lock design that is said to guarantee centreline repeatability of ±0.1mm when changing from one solid carbide tool shank to the next. The system works with a rotating locking screw that pushes the tool insert downwards and back against a locating pin to deliver a high degree of rigidity, repeatability and tool life. This allows solid carbide boring, threading, grooving and profiling tools to be interchanged within 30 seconds, cutting machine downtime and improving set-up procedures.

The new toolholders are precision ground for a concentricity of less than ±0.01mm and are heat treated to extend their tool life. In addition, the holders have a through hole and adaptor for through-coolant machine tools. The QTH series are imperial dimension holders with shank diameters of 0.5, 0.625, 0.75, 1 and 1.25in and an overall length of 2.750in. The internal diameter for clamping the carbide tool shank varies from 0.1875 to 0.5in whilst an extended length version is available with an overall toolholder length of 5.8in.

For metric machine shops, the QTHM line of toolholders is available with a diverse range of dimensions to suit all machine types. The QTHM series is available in all standard sizes that include 12, 16, 20, 22, 25 and 32mm shanks. This diverse range of diameters makes the QTHM and the QTH suitable for installation on sliding head turning centres with small toolholder capacity and platen availability. In addition, the quick change configuration of the toolholders is said to come into its own on small machines that make access to the tool platen and the respective changeover process difficult. Simultaneously, with 25 and 32mm shank options available, the MicroQuik toolholders can easily be applied to larger more robust turning centres.