Brass Mold-In Inserts

Precision Threading Solutions for Injection Molding
High-quality Brass threaded inserts Brass Mold in inserts designed for permanent installation in plastic components through injection molding processes
Product Overview
Brass mold-in inserts represent the pinnacle of threaded fastener technology for injection molded plastic components. These precision-engineered inserts feature a coarse diamond knurl exterior surface that creates an unbreakable mechanical bond with the surrounding plastic material during the molding process. Unlike post-molding installation methods such as heat insertion or ultrasonic welding, mold-in inserts are positioned directly in the injection mold cavity, allowing the molten plastic to flow around and permanently encapsulate the knurled exterior. This results in superior pull-out resistance, exceptional torque strength, and eliminates the risk of insert displacement or rotation. The internal threads are precision-machined to exact specifications, providing reliable engagement with standard fasteners while the brass construction offers excellent corrosion resistance, electrical conductivity, and thermal stability across a wide temperature range.
🔄 Through Hole Inserts
Complete thread engagement from both sides with coarse diamond knurl exterior for maximum retention in plastic materials. Ideal for applications requiring access from both ends.
🔒 Blind Hole Inserts
Closed bottom design with internal threads and diamond knurl exterior. Perfect for applications where one-sided access is sufficient and bottom sealing is required.
Available Thread Sizes
2-56 UNC
Fine precision threading
4-40 UNC
Small component applications
6-32 UNC
Standard electronics threading
8-32 UNC
Medium duty applications
10-24 UNC
Heavy duty small threads
1/4″-20 UNC
Standard quarter-inch threading
5/16″-18 UNC
Large diameter applications
Dimensional Specifications

Through Hole Insert Dimensions
| Thread Size | B – Thread Length (in) | C – Overall Length (in) | D – Insert Diameter (in) | E – Thread Diameter (in) | F – Flange Thickness (in) |
|---|---|---|---|---|---|
| 2-56 UNC | 0.156 | 0.218 | 0.125 | 0.086 | 0.031 |
| 4-40 UNC | 0.187 | 0.250 | 0.156 | 0.112 | 0.032 |
| 6-32 UNC | 0.218 | 0.281 | 0.187 | 0.138 | 0.032 |
| 8-32 UNC | 0.250 | 0.312 | 0.218 | 0.164 | 0.032 |
| 10-24 UNC | 0.281 | 0.343 | 0.250 | 0.190 | 0.032 |
| 1/4″-20 UNC | 0.343 | 0.406 | 0.312 | 0.250 | 0.032 |
| 5/16″-18 UNC | 0.406 | 0.468 | 0.375 | 0.312 | 0.032 |
Blind Hole Insert Dimensions
| Thread Size | B – Thread Depth (in) | C – Overall Length (in) | D – Insert Diameter (in) | E – Thread Diameter (in) | F – Flange Thickness (in) |
|---|---|---|---|---|---|
| 2-56 UNC | 0.125 | 0.187 | 0.125 | 0.086 | 0.031 |
| 4-40 UNC | 0.156 | 0.218 | 0.156 | 0.112 | 0.032 |
| 6-32 UNC | 0.187 | 0.250 | 0.187 | 0.138 | 0.032 |
| 8-32 UNC | 0.218 | 0.281 | 0.218 | 0.164 | 0.032 |
| 10-24 UNC | 0.250 | 0.312 | 0.250 | 0.190 | 0.032 |
| 1/4″-20 UNC | 0.312 | 0.375 | 0.312 | 0.250 | 0.032 |
| 5/16″-18 UNC | 0.375 | 0.437 | 0.375 | 0.312 | 0.032 |
Key Features & Benefits
Material Properties
- High-quality brass construction (360 brass alloy)
- Excellent corrosion resistance
- Superior thermal conductivity
- Non-magnetic properties
- Electrical conductivity for grounding applications
Design Features
- Coarse diamond knurl exterior for maximum retention
- Precision machined internal threads
- Uniform wall thickness for consistent performance
- Chamfered entry for easy installation
- Available in through-hole and blind configurations
Installation Benefits
- Molded directly into plastic components
- No secondary operations required
- Permanent installation prevents loosening
- Superior pull-out and torque resistance
- Cost-effective alternative to tapping plastic
Applications
🔌 Electronics
PCB mounting, enclosure assembly
🚗 Automotive
Interior components, trim assemblies
🏠 Appliances
Housing assemblies, control panels
🔧 Industrial
Equipment housings, control boxes
🎮 Consumer Goods
Device housings, toy assemblies
🏥 Medical
Device housings, instrument panels
Installation Guidelines
Mold Design Considerations
- Position insert in mold cavity before injection
- Ensure proper alignment with mold features
- Design adequate clearance for insert placement
- Consider gate location to minimize stress
- Use appropriate mold temperature (300-350°F typical)
Plastic Material Compatibility
- ABS – Excellent retention and performance
- Nylon – Superior strength and durability
- Polycarbonate – High temperature applications
- PBT/PET – Chemical resistance applications
- Polypropylene – With proper surface treatment
Quality Standards
📏 Precision
±0.002″ dimensional tolerance
🔍 Inspection
100% dimensional verification
✅ Standards
ANSI/ASME B18.8.2 compliant
🏆 Certification
ISO 9001:2015 manufacturing
Ready to Enhance Your Molding Process?
Contact us today for technical specifications, samples, or custom sizing options





