Blind Threaded Brass Inserts with Closed End Design
Lead-free custom precision fasteners designed for clean injection
molding applications
Blind Threaded Brass Inserts Overview
In insert molding processes, molten plastic easily seeps into the
threads of through-hole nuts, requiring additional tapping cleanup
operations that add cost and time. Our brass inserts with blind
closed-end design structurally block plastic melt from entering the
threaded area, eliminating post-processing steps while ensuring
thread cleanliness and integrity for reliable screw fastening.
Precision Manufacturing Process
Using Swiss-type lathes, we complete turning, drilling, tapping,
and end-face closure in a single setup, ensuring uniform bottom
wall thickness with no leakage risk. The closed-end design acts as
a physical barrier during insert molding, completely blocking
molten plastic from entering the threaded area. After ejection, you
receive finished components with clean threads requiring no
secondary operations.
This design is particularly valuable for micro inserts (M2-M3)
where thread cleaning is difficult and prone to damage. As a
certified factory with 15 years of precision manufacturing
experience serving 2,000+ global clients, we are committed to
eliminating hidden costs and quality risks from your production at
the design stage.

Product Features & Advantages
| Feature | Advantage to You |
|---|
| Completely Eliminates Flash Issues | Closed-end design creates a physical barrier that completely blocks
plastic melt from entering the threaded area during insert molding.
Eliminates post-cleaning steps, reducing manufacturing cost and
improving production efficiency. |
| Protects Thread Precision & Cleanliness | No secondary tapping required; threads remain in factory-precise
condition. Ensures consistent screw fastening torque, avoiding
stripping or insufficient clamping force due to incomplete
cleaning. |
| Ideal Choice for Micro Inserts | For micro threads like M2 and M2.5, cleaning easily damages thread
profiles. Blind hole design fundamentally solves this issue, making
it the preferred solution for precision micro assemblies. |
| Customizable Blind Depth & Wall Thickness | We can customize blind hole depth and bottom wall thickness based
on your mold design and strength requirements. Ensures anti-flash
functionality without compromising overall insert strength. |
| 15 Years Precision Turning Expertise | Swiss-type lathes complete machining in one setup, ensuring uniform
bottom wall thickness. IATF16949 certified quality with high
batch-to-batch consistency. |

Product Specifications
| Specification Item | Detail / Capability | Notes / Description |
|---|
| Blind Thread Range | M2, M2.5, M3, M4, M5, M6 | Common metric sizes; unified custom available |
| Body Size Range | OD: 3mm-10mm; Length: 4mm-15mm | Blind depth customizable |
| Bottom Wall Thickness | Min 0.5mm / Adjustable per injection pressure | Ensures no leakage risk |
| Anti-Rotation Options | External Knurling / Annular Grooves / Hex Profile | Multiple options available |
| Material Options | Lead-Free Eco Brass / C3604 Free-Cutting Brass | Material certs provided |
| Recommended Process | Insert Molding / Heat Staking | Blind design suitable for both |

Product Applications
- Automotive Electronic Connectors: For sensor housings and ECU
connectors where sealant or potting compound must be kept out of
threads.
- Medical Device Enclosures: For monitor and diagnostic equipment
housings requiring clean internal threads for sterilization
readiness.
- High-End Consumer Electronics: For threaded connection points in
smartphone frames and tablet back covers that must be used directly
after insert molding.
Frequently Asked Questions
Can you handle complex custom designs and provide design
optimization suggestions?
Absolutely. This is our core expertise. We provide free DFM
analysis within 3-5 days, often helping clients achieve 15-30% cost
reduction through design for manufacturability.
How do you ensure quality consistency and handle defect issues?
We implement a rigorous 4-stage QC system with 100% full
inspection. Our track record shows 99.99% qualification rate.
What are your lead times and how do you handle urgent orders?
Standard lead times: 3-7 days for prototypes, 7-15 days for mass
production. We offer VIP prioritization cutting lead times by up to
30%.
Will I get timely responses and professional support throughout the
project?
Yes. You get a 1v1 exclusive consultant with 1-hour initial
response commitment and 24-hour technical support.
Can you provide material certifications and environmental
compliance reports?
Yes. We provide material certifications and environmental test
reports (RoHS, REACH compliant) upon request.
How do you protect my designs and intellectual property?
We start with mutual NDA and implement strict mold ownership
protection and confidential data security measures.
What are your payment terms and MOQ requirements?
We offer flexible payment terms (T/T, L/C at sight) and MOQ from 1
piece for prototyping.