🔩 Types of Brass Inserts: A Complete Guide for Plastic Assembly & OEM Applications

The Ultimate Resource for Engineers, Buyers, and Product Developers

When it comes to improving thread strength, fastening durability, and assembly reliability in plastic or soft materials, brass inserts are a go-to solution across industries. But selecting the right type of brass insert depends on the material, application method, and functional requirements.

This guide covers the main classifications, design structures, installation methods, and industry applications of brass inserts to help you make informed sourcing decisions.

📌 What Are Brass Inserts?

Brass inserts for plastic are precision-machined metal components with internal threads, used to provide strong threaded connections in soft base materials such as thermoplastics, thermosets, wood, and composites. These inserts are commonly used in plastic injection molded parts, electronic housings, automotive panels, and consumer goods.

🔧 Brass Insert Types by Installation Method

1. Heat-Set Brass Inserts

Installed using a heated tip that softens the plastic and embeds the insert.
✅ Strong pull-out resistance
✅ Ideal for thermoplastics

2. Ultrasonic Brass Inserts

Inserted using ultrasonic vibration, which melts the plastic locally to grip the insert tightly.
✅ High precision
✅ Compatible with automated lines

3. Press-In Brass Inserts

Pushed mechanically into a pre-molded or drilled hole.
✅ No heat required
✅ Perfect for thermosets, wood, and soft metals

4. Molded-In Brass Inserts

Placed directly into the mold before the plastic is injected.
✅ Most permanent option
✅ Delivers maximum strength

🧱 Brass Insert Types by Structural Design

Knurled Brass Inserts

Feature external knurling (straight, diamond, or helical) to enhance grip.
✔️ Anti-rotation
✔️ Torque resistance

Hex Brass Inserts, Download The Price List for The Hex Brass Inserts Right Now

The hexagonal body fits tightly into hex-shaped cavities.
✔️ Maximum torque resistance
✔️ Strong mechanical lock

Threaded Brass Inserts

Standard internal threads (M2–M10 or inch sizes) for repeat use.
✔️ Precision fit
✔️ Widely used in electronics and plastics

Self-Tapping Brass Inserts

Cuts its thread into the host material upon insertion.
✔️ Fast installation
✔️ No pre-threading needed

🏭 Application of Brass Inserts in Different Industries

📦 Electronics

• Used for: PCB mounting, connectors, plastic enclosures

• Benefits: Compact size, corrosion resistance, repeatable threading

🚗 Automotive

• Used for: Dashboards, panel assemblies, control modules

• Benefits: High-temperature resistance, mechanical stability

We specialize in manufacturing high-quality auto parts through CNC machining services and sheet metal fabrication. [Click here] to explore our capabilities

🪑 Furniture

• Used for: Wood joint fasteners, shelf brackets

• Benefits: Quick assembly, reliable torque retention

🏗️ Industrial OEM

• Used for: Structural frames, mechanical connections

• Benefits: Vibration-proof, long-term reliability

✅ Real Case: Custom M6 Hex Brass Insert for Automotive Plastic Shell

We (Machiningfabtech ) have been supplying a custom M6 hex brass insert to one of our automotive customers since 2019. It is designed for injection-molded plastic shells for car body assemblies, requiring both strong thread performance and resistance to vibration.

• Thread Specification: M6

• Hex Width Across Flats: 10 mm

• Total Length: 23 mm

• Net Weight: 0.0086 kg

• Material: brass H59

• Installation Method: Molded-in during plastic injection

This part demonstrates our capability to deliver high-precision inserts for automotive OEM applications. Download the technical drawing of threaded brass insert here.

📐 Technical Specifications We Offer

• Material: C3600 Brass / Lead-Free Brass (ROHS compliant)

• Thread Sizes: Metric M2–M10 or inch equivalents

• Surface Finish: Plain, Nickel-plated, Tin-plated

• Tolerance: ±0.01 mm (custom tolerances available)

• MOQ: Flexible, starting from a small batch

• Service: Full OEM & ODM machining support

🤝 Work With a Trusted Brass Insert Manufacturer

As an ISO-certified brass insert supplier in China, we offer:

• Competitive pricing with reliable lead times

• One-stop support from prototyping to mass production

• Strong quality control and technical support

• Worldwide shipping (Europe, USA, Oceania)

📩 Get a Quote Today or send your drawings to cindy@machiningfabtech.com — let’s create solutions that last.

🔗 Related Resources:

• What Is CNC Machining? Complete Guide for Beginners