302/307/308/337/338 Series Metric & Inch Self Tapping Thread Insert For Plastics, Light Alloys & Metals

1.What is FH Self Tapping Thread Insert
FH self tapping threaded insert is a one-piece threaded fastener integrated with internal standard thread and self-tapping external thread with cutting slots or chip storage bores, developed and produced by Xinxiang Flight Fasteners (Zhonghang Feihang) with over 20 years professional thread insert manufacturing experience.

Different series are customized for different workpiece materials:
 

• 302 Series: Double cutting slot design, specially for low shear strength materials: plastic, laminate, hardwood, light alloy, cast iron, brass bronze. It generates tiny cuttings during installation without chip pollution risk.
• 307/308 Series: Single cutting bore structure, optimized for medium & high shear strength metals (carbon steel, alloy steel, thick cast iron). Longer pull-out resistance under heavy dynamic load.
• 337/338 Series: 3 peripheral chip storage reservoirs, exclusive for electronic, precision equipment where metal scraps will cause circuit short or component failure, all cuttings are sealed inside insert body.
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2.Core Advantages of FH Self Tapping Thread Insert

1. Strengthen weak base material threads
   Directly form high-strength standard internal thread on soft plastic, aluminum alloy, magnesium alloy, preventing thread slipping, stripping and failure under repeated disassembly.
2. Perfect damaged thread repair solution
   No need to enlarge hole or rework workpiece; install self tapping insert to restore standard thread specification, save scrap cost of broken parts.
3. Simplify production process
   Skip pre-tapping process for injection molding, die casting parts. Only drill bottom hole then screw insert in, improve production efficiency and finished product yield.
4. Compact lightweight structural design
   Higher bearing capacity than ordinary thread, allow smaller hole layout and thinner wall thickness, realize miniaturized product design for consumer electronics, automotive parts.
5. Strong anti-vibration & pull-out performance
   Self-tapping external thread closely bites workpiece base material, no loose under long-term vibration working condition (engine, new energy vehicle, wind power equipment).
6. Diversified structure options for different scenes
   Standard straight body, hex socket drive, shoulder flanged head, chip storage type; meet blind hole, through hole, multi-layer stacking assembly, precision electronic assembly requirements.
7. Rich material & surface finish selection
   Case hardened steel, stainless steel 304/303/316F, titanium alloy, brass; multiple surface treatments including blue zinc passivation, yellow chromate, zinc-nickel transparent passivation, meet corrosion resistance and environmental standards (RoHS, REACH, ELV).

3. Complete Product Series Classification
3.1 302 Series (For Low Shear Strength Materials)

1. 302 0 Standard Straight Body Self Tapping Insert
   Basic model with dual cutting slots, metric M2-M30, UNC/UNF inch thread sizes.
2. 302 2 Hex Socket Self Tapping Insert
   Internal hex drive hole, quick installation with hex screwdriver, electric torque tool, reusable extraction allowed.
3. 302 1 Flanged Shoulder Self Tapping Insert

Circular locating head, support multi-layer parts clamping, greatly improve pull-through force when axial load applied on shoulder.

3.2 307 / 308 Series (For Medium & High Strength Metals)
 

• 307: Short body length, thin wall, limited installation depth blind hole use
• 308: Long body length, larger contact area, ultra-high pull-out strength
  Derivatives: 307 2 / 308 2 Hex socket type; 307 1 / 308 1 Flanged shoulder type

3.3 337 / 338 Series Chip Storage Self Tapping Insert

Three surrounding chip storage cavities, block metal cuttings falling into precision electronic components, ideal for PCB equipment, sensor, aerospace electrical modules. Short body 337, long body 338.

4. Main Technical Parameter Table
Metric Thread 302 Series Dimension Data

Inch UNC/UNF 302 Series Dimension Data