# 302/302H Self-Tapping Inserts · Selection notes

External cutting features engage a prepared pilot hole. Matching the hole to the parent material is essential for successful self-tapping installation.

## How it works

Type 302 self-tapping inserts use cutting slots to form a mating external thread in a suitable parent material as they are installed, while providing an internal screw thread. Pre-tapping requirements and pilot-hole dimensions depend on the material and approved process. Self-tapping does not mean that any hole size is suitable.

## Selection guidance

- 302 / 302H：Existing model names are retained. Confirm the meaning of the H suffix against the ZCOIL drawing.
- Parent material and pilot hole：Determine according to hardness and machining method.
- Cutting and chip removal：Allow space for cutting and cleaning.
- Geometry and material：Check outside diameter, length, head geometry and material.

## Installation overview

1. Confirm the material and hole：Check the parent material, pilot hole and effective depth.
2. Mount on the installation tool：Maintain secure engagement between the tool and insert.
3. Install in alignment：Maintain alignment and control insertion according to the approved procedure.
4. Inspection and cleaning：Check the installed position and remove machining debris.


Actual dimensions, performance and installation must follow the approved drawings and technical agreement.

Contact: info@zcoiltech.com / +86 136 0303 3992