# 307/337/307H Blind-Hole Self-Tapping Inserts · Selection notes

Consider pilot-hole depth, cutting features and chip accommodation together. Similar model names do not imply the same chip-retention capability.

## How it works

In comparable self-tapping designs, the cutting holes of type 307 differ from the chip cavities of type 337. A type 337 cavity provides space near the cutting zone for chips. A blind hole describes the parent material; it does not imply a closed-bottom insert or a chip-free installation.

## Selection guidance

- Model differences：Confirm the structures of 307, 337 and 307H separately.
- Effective depth：Check hole depth, insert length and screw length separately.
- Chip accommodation：Confirm the cross-section; the label "blind-hole type" is not sufficient.
- Cleaning and sealing：Specify each requirement separately; they are not interchangeable.

## Installation overview

1. Check the section drawing：Confirm cutting holes, chip cavities and bottom geometry.
2. Prepare the blind hole：Check effective depth and bottom clearance.
3. Install to the approved procedure：Maintain alignment and prevent the insert from bottoming out too early.
4. Inspect residual chips：Inspect and clean according to the component's cleanliness requirements.


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

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