Time to Reconsider Holding Taps with Collet Chucks
Alan Miller
undoubtedly one of the more challenging metalworking processes to execute with precision in volume. Generations of machinists that came before, however, likely wouldn’t be too sympathetic. As recently as the 1980s, tension-compression tapping was widespread. This involved underfeeding tapping holders with springs, allowing the tap to travel independently on the way in and out – a painstaking process that could only be performed at rpm levels in the hundreds. In the years since, machine builders have done their part to help spare machinists the pain sometimes associated with the process. Thankfully, most machine tools now come with canned
cycles allowing for M-code and G-code pairings that precisely synchronize the spindle and feed axis for repeatable harmony with the workpiece . . . rigid and synchronous tapping. Built-in encoders can even monitor these activities and adjust the machine to maintain the proper relationship between feed and speed. Thanks to these advances, machines can now perform tapping with spindle speeds exceeding 4,000 rpm. Still, in the wake of these dramatic advances, limited tap life, poor thread pitch or tolerance and, most impactful, broken taps can keep machinists up at night and cost shops efficiency. Regardless of programming enhancements,
The next time you think about setting up a tapping operation with a collet chuck the same old way you always have, you may want to think again. There are now tap holders designed specifically to mitigate the load imposed on the tap
by essentially absorbing synchronization error.
Tapping holes strikes fear
in the hearts of machinists everywhere. Ok, that may be a bit of an exaggeration, but it is
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