When threads are cut with fully-synchronized machine tools, the threading tool is often tensioned using a conventional tapping chuck. However, as the exhibitors insist, a 100-percent synchronization of the machine tool is not possible due to the tolerances in the drives and feed guides or because of differing thermal expansions. As is explained, the threading tool can often break when the full depth of the thread has been reached and when the direction of rotation changes. To avoid such problems and enhance process reliability, commercially available soft-synchro chucks were developed with minimum length compensation in the axial direction. However, these chucks are usually equipped with disc springs or plastic discs, which either wear out or harden due to the coolant. These minimal length compensations also exert high pressure on the tool or its flanks. The company says it has solved this problem with the Synchrofit (SFH) tapping holder. This has a steel cage (patented cutting pressure compensator), a clamping nut with an integrated pressure ring for maximum concentricity and a coolant transfer unit, so pressure can be compensated both axially and radially, and this new radial force compensation is said to considerably reduce wear on the flanks.
Tapping holder with integrated intelligence
One of the highlights from OSG will be the Synchrofit (SFH) tapping holder, which has a steel cage (patented cutting pressure compensator). The first practical trials have reportedly shown that tool life can be increased by up to 20 percent over conventional soft-synchro chucks.