Fluteless forming taps: internal threads without chips

Forming taps produce the internal thread not by cutting but by displacing the material. The grain flow is preserved, the thread is stronger than a cut one, and there are no chips to get in the way in a blind hole. VÖLKEL makes fluteless forming taps to DIN 371 and DIN 376 in HSSE, bright, with VAP treatment or TiN coating, with and without lubrication groove, in tolerances 6H, 6G, 6H TiN and 6H VAP.

When to form instead of cut?

Thread forming requires a material that can be cold-formed: unalloyed and low-alloy steels, structural steels, heat-resistant and stainless steels, long-chipping non-ferrous metals such as aluminium, bronze, copper and brass, and zinc alloys. For grey cast iron, thermosets or very hard steels the machine tap remains the right tool.

The advantages at a glance

• longer tool life than a cutting tap and higher permissible speed
• consistent dimensional and profile accuracy over the whole tool life
• higher load capacity of the formed thread thanks to the preserved grain flow
• high breakage resistance of the tool, as there are no cutting edges to chip
• no chip problem, so ideal for blind holes and through holes

Choosing the version

Bright for non-ferrous metals with good formability, VAP for steels up to about 700 N/mm², TiN for steel up to about 900 N/mm² and for higher speed and tool life. The version with lubrication groove carries the lubricant right to the forming zone and has the advantage in deep threads and tough materials.

The pilot hole is larger

Because the material flows into the profile, a forming tap needs a larger pilot hole than a cutting tap: 5.55 mm instead of 5.0 mm for M 6, 9.30 mm instead of 8.5 mm for M 10, 11.20 mm instead of 10.2 mm for M 12. The complete series from M 1 to M 16 is in the technical information for the product. Experience from a run of more than 50,000 threads is in Thread forming: what really matters, the basics in Thread forming: chipless, clean, reliable.