Tapping Heads (Tap Holders): Working Principle and Advantages

Posted by Ece Küçükoğlu on
Tapping Heads (Tap Holders): Working Principle and Advantages

In machining operations (on CNC machining centres, lathes and pillar drills), tapping heads (tap holders) are used to prevent breakage of the taps used for cutting screw threads and to achieve an accurate thread pitch.

Watch Temak Teknik’s informative video below showing the types of tapping heads, their float mechanism and quick tap changing:

Working Principle and Advantages of Tapping Heads

  1. Spring Compensation and Synchronisation (Float Mechanism): When tapping ends, or at the moment the spindle reverses from clockwise to anticlockwise rotation, momentary synchronisation differences can occur between the machine’s Z-axis feed and its rotation. The axial spring mechanism inside the head compensates for this difference and play, absorbing the excess load on the tap [00:18].
  2. Preventing Tap Breakage and Extending Tool Life: The float springs cushion sudden loads caused by chip packing during cutting or at the moment of reversal. This prevents the tap from chipping or breaking, avoiding scrapped workpieces and damage to the machine [01:24].
  3. Fast and Easy Tap Change: Thanks to the secure ball/latch mechanism on the head, the tap can be changed easily within seconds, with or without an adaptor, without removing the holder from the spindle or turret [00:59].

Connection and Shank Types

  • Machine Connection Types: For machining centres and lathes, BT30, BT40, BT50 and HSK-63 taper types are available, as well as straight (cylindrical) shank models and special taper types for drilling machines [01:53].
  • Size and Metric Adaptor Selection: For each thread size (e.g. M6, M8, M10, etc.), a tap adaptor of the appropriate size is inserted into the holder. For taps of different diameters, a head or tap adaptor of the matching size should be selected [02:23].

Fitting and Changing Steps

  1. Fitting the Mechanism: The tap adaptor is seated in its socket and locked by pulling back the collar on the main body [02:42].
  2. Securing the Tap: The tap of the corresponding metric size is inserted into the socket by pressing the locking mechanism at the front of the adaptor [03:00].
  3. Movement Check: Once fitted, the system has no radial (side-to-side) play; it provides axial float only along the Z axis (up and down) [03:13].