Lead-in
The lead-in is the front portion of a tap or die where the thread "engages" and the cutting process begins.
When tapping threads, this means:
- The lead-in makes it easier to position the tool and reduces cutting forces.
- The lead-in zone influences how cleanly the thread starts and how much load acts on the cutting edges.
Practical example:
A tap with a long lead-in starts more gently into the material – particularly useful with soft or sensitive workpiece materials.