Brass inserts manufacturers & Supplier For USA and Europe

Brass Inserts Manufacturers | Custom OEM Brass Inserts

We are an OEM brass insert manufacturer. We produce custom brass threaded inserts for electronics, plastic injection molding, electrical assemblies, automotive components, and 3D printed parts.

All the brass inserts will be manufactured according to customer drawings, samples, and specifications. We support custom thread sizes, knurl patterns, dimensions, and designs as per buyer requirements. We manufacture custom brass inserts in various designs such as straight knurls, diamond knurls, flanged, blind, slotted, and through-thread configurations. These threaded brass inserts can be produced for heat-set, press-fit, ultrasonic, and molded-in applications.

We supply brass screw inserts to customers in the USA, Europe, and Asia. We support medium- to high-volume production requirements. A sample and a small batch are also supported for quality and testing.

Send Your Drawing for a Custom Brass Insert Quote

Brass Inserts – Specifications & Capabilities

Specification	Details
Manufacturing Method	Dedicated automatic brass insert machines CNC turning only for large or special inserts
Materials	Brass C36000 (default) CZ121 and other brass grades on request
Insert Types	Brass press-in inserts Brass heat-set inserts Brass mold-in inserts Inserts suitable for ultrasonic installation
Typical Size Range	Small to big inserts used in plastic molding (exact limits reviewed per drawing)
Thread Types	Metric (M-series) UNC and UNF threads Blind or through threads as per design
Knurl Type	Controlled rolled knurl for plastic retention
Dimensional Control	OD typically around ±0.05 to ±0.10 mm depending on size Roundness controlled around 0.05 mm on critical diameters
Thread Control	Go/No-Go gauge checks at regular intervals during production
Surface Finish	Nitric finish as default Brushed finish for visible parts Nickel, tin, silver plating via partners
Inspection	Visual check for burrs Gauge check on OD and threads
Material Certification	Available on request
Packaging	Bag + label for standard orders Master Box + Wooden pallet
Lead Time	Repeat jobs: 15–20 working days New tooling/plating: 20–25 working days
Drawings Accepted	STEP (3D), PDF, DXF, and DWG files

Why Use Brass Inserts?

Insert is not just shiny threaded part. It is the perfect balance of strength, corrosion resistance, and thermal conductivity. In plastic molding application, it flow better and does not deform under pressure but soft might be. Brass threads stay clean and resist galling. they do not strip the moment someone grabs screwdriver too hard.

Brass Inserts make assemblies stronger and cleaner. Instead of just forcing screws into plastic, you get repeatable torque and reusability. No cracks and stress marks. Just a solid, finished feel.

Brass Inserts for Plastic Injection Molding

Brass inserts are widely used in plastic molding. They create strong and repeatable metal threads inside plastic parts. Direct screws often strip plastic bosses over time, so inserts are preferred.

Types of Brass Inserts and Installation Methods

We manufacture brass inserts for all major install types such as press-fit, heat set, ultrasonic and mold-in. Each needs a different outside diameter geometry, knurling and tolerance. If insert will wrong match? We will insert spins, cracks part and pull out. We cut them right so your installation process will run soooth.

Press-In Brass Inserts

Press-in brass inserts work best in rigid plastics. Rigid plastics accept interference fit better. They allow fast assembly in high-volume production. But they need tight outer diameter control and consistent knurling to avoid spin-out. When sized correctly, press-in inserts give reliable pull-out resistance.

• OD Design: Straight wall and slightly tapered


• Knurl Type: Diamond and straight for perfect grip


• Material Fit: Works best for ABS, Nylon, soft PC


• Use Case: Mounting bosses, standoffs, threaded holes in rigid plastic housings


• Risk: Over pressing can crack thin walled parts

In assemblies that require PCB spacing, aluminum spacers can be used alongside press-in inserts. The insert provides the threaded fastening point, while the spacer maintains the required distance between components.

Brass Heat Set Inserts

Brass heat set inserts are installed into a pre-molded hole using a heated tool. The heat softens the plastic around the insert. Soft plastic flows into the knurl pattern. When it cools, it hardens and locks the insert in place. This method is used when stronger and more consistent retention is required. It also gives better alignment control than press-fit.

• OD Design: Tapered entry, vented or open-ended


• Knurl Type: Helical or diamond


• Plastic Types: Nylon, ABS, PC, PEEK heat tolerant plastics


• Tooling: Hot-tip soldering iron, thermal press, CNC controlled heater


• Critical Detail: OD taper must match hole ID to avoid float and sink

Mold-In Brass Inserts (Pre-Insert and Post-Mold Insert)

Mold-in brass inserts are placed inside the mold before injection. Molten plastic flows around the insert during molding. As the plastic cools, it forms a mechanical lock with the knurl. No extra installation step is needed. Manufacturers use this for structural housings and heavy-load threaded features.

• OD Design: Flanged or barbed to resist pull


• Knurl Type: Straight grooves or anchor fins


• Usage: Plastic enclosures, connectors, threaded caps


• Advantages: Zero secondary process, strongest mechanical lock


• Requirement: Mold design must allow accurate insert placement

Ultrasonic Brass Inserts

Installation using vibration and pressure. Ultrasonic horn vibrates at high frequency, creating heat from friction between insert and plastic then softens plastic and lets the insert sink in.

• OD Design: Shorter length, precise diameter


• Knurl Type: Spiral or multi-start diamond for grip


• Application: Fast install for mass production


• Risk: Too sharp a knurl, wrong horn can overheat and cause flash marks


• Ideal For: Thin-walled parts, tight spacing, automated assembly

Brass inserts work reliably in common engineering plastics such as ABS, Nylon, Polycarbonate (PC), and heat-resistant plastics like PEEK. Performance still depends on boss design, wall thickness, and installation method.

Brass is commonly preferred over aluminum for plastic inserts because it resists corrosion and machines easily. Stainless steel is usually chosen only when higher temperature and strength is required.

For detailed thread sizing, classes, and tolerance control, see our brass threaded insert page.

Materials - What We Machine Daily

We do not run custom brass alloy. We stock and machine known grades, tight batch control.

• C360 - Best for sharp threads, dry machining


• CZ121 - For fine knurling, good chip control


• C385 - Great for molded-in inserts, smoother tool feed

Each grade cuts differently. We have to adjust speed, chip break, and tooling based on grade. In our one batch of PO-145 needed a new knurling insert at mid-batch due to edge wear. cleaned the groove, ran the rest smooth.

Brass Inserts Manufacturer Capabilities

We manufacture most brass inserts on dedicated automatic brass insert machines, not general CNC lathes. CNC turning is used only for large inserts requiring special features and tighter tolerances.

Production is based on repeatable, dedicated setups for each part number. All inserts are made strictly as per customer drawings for plastic molding and assembly use.

Machining Scope

Standard brass inserts are produced on special-purpose automatic brass insert machines. This SPM machine designed for high repeatability and stable thread quality.

CNC turning is used only when required for:

• Big inserts
• Complex geometry
• Special tolerances
• Non-standard profiles

Blind threads and short thread lengths are produced with controlled threading methods suited to brass inserts. Thread depth and profile are maintained consistently across batches.

Production threads are cut using tools selected for stable pitch and long tool life.

Threads are not forced with soft taps or uncontrolled methods.

Knurls are formed by controlled rolling, treated as a functional feature for plastic retention, not decoration.

Dimensional Control

Outside diameter is typically controlled around ±0.05 to ±0.10 mm depending on insert size and application, and checked on every batch. Knurl height is set to suit your plastic boss.

Roundness is normally controlled around 0.05 mm on critical diameters where required.

Internal thread pitch is verified using Go/No-Go gauges at regular intervals during production.

Process Discipline

Each insert design uses dedicated tooling for that part number, whether run on automatic insert machines or CNC. Tooling and setups are logged and tracked for repeat orders.

Setup records include spindle speed, tool offsets, and fixtures for consistency. The same collets, clamps, and tooling configuration are used for repeat production.

Cutting and threading tools are monitored for wear and replaced before they can affect quality.

Surface Finish and Post-Process

Tumbled finish is the default to remove sharp edges and chips.

Nickel, tin, and silver plating is done through certified partners. After plating, all inserts receive full inspection to detect thread buildup and fit issues.

Quality Checks You Actually Get

Every batch receives visual inspection for burrs and chip smears. Critical ODs and internal threads are checked with gauges.

Where required, inserts are fit-tested in sample plastic blocks.

Packaging and Logistics

High-precision threaded inserts are packed in trays to protect threads. Standard orders are packed in bags with clear labeling, master box and wooden pallet.

Lead Time

Repeat jobs normally ship in 15 to 20 working days. New tooling, special plating, and design changes can extend lead time to 20 to 25 working days.

Small batches are usually sent by air freight. Large volumes are shipped by sea to reduce cost.

Actual lead time can vary based on raw material availability and plating schedules.

Threads - Internal, External, Cleaned Before Ship

• Metric: M2 to M16


• UNC/UNF: 4-40, 6-32, 10-32, 1/4-20


• BSP, NPT available on request


• Through-threaded, blind, closed bottom


• Side-tapped inserts supported


• Tap cleaned, chamfered, light deburr pass on every batch

Maintaining tight thread tolerances requires high-end equipment. While we specialize in inserts, our facility is fully equipped for complex CNC Parts that require multi-axis turning. Many clients ask us about pricing for high-precision work; we actually published a guide on why CNC machining custom parts can be expensive to help engineers optimize their designs for lower production costs.

Tolerances - What We Actually Hold

We do not write ±0.10 mm and hope. We measure. We track. We scrap if needed.

• OD tolerance: ±0.05–0.10 mm typical


• Thread pitch: Go/No-Go checked every 10 to 15 pcs


• Knurl height: Controlled within ±0.10 mm on press-fit specs


• Roundness: Within 0.05 mm on most diameters

Our factory use micrometers, bore gauge and optical comparators for quality checks. No tolerance is “close enough.” We once had to re-run 5000 inserts when a collet slipped and gave us +0.04 mm on OD. Fixed it, logged it, ran it again. Clean.

Application Industries We Supply Brass Inserts To

• Injection Mold Builders (USA, Europe)


• Electronics & PCB Assemblers (Germany, South Korea)


• Automotive Plastic Components (UK, India)


• Medical Equipment Makers (USA, EU)


• Consumer Goods (Global)

Brass Insert Buyer FAQ

1. Do you make standard catalog brass inserts or only custom?

We manufacture custom OEM brass inserts only. All parts are made strictly according to buyer drawings and requirements. We do not sell catalog and off-the-shelf inserts. .

2. Can you quote and manufacture inserts without a drawing?

A drawing is normally required to quote and manufacture. If a drawing is not available, you must provide a physical sample part for review.

3. Do you support samples before mass production?

Yes. We support 5 to 10 sample pieces or a small pilot batch before full production. Mass production starts only after sample approval.

4. What minimum quantity do you accept?

We do not accept quantities that do not justify tooling and setup cost. Very small one-time orders are reviewed case by case. We focus on medium, large and repeat OEM quantities.

5. What surface finish is normally provided on brass inserts?

Our default surface treatment is tumbled and nitric for brass. Additional finishes such as nickel, tin, and silver plating are provided through qualified partners as per drawing. Raw, untreated inserts are not supplied.

6. Which plastics are compatible with brass inserts, and does my material affect the insert design?

Yes, plastic type directly affects which insert type, knurl pattern, OD tolerance, and hole size are needed.

• Heat-set and ultrasonic inserts only work with thermoplastics.
• Press-fit and mold-in inserts can be used with both thermoplastics and thermosets.

For softer plastics like PP and HDPE, press-fit is preferred since heat-set may not produce enough grip. If you are working with glass-filled or carbon-filled grades, the insert OD and knurl geometry need to be tuned because filled plastics resist plastic flow differently.

7. Who owns the tooling for custom brass inserts?

All tooling, dies, and fixtures developed for your part are customer-owned. Tooling is never reused for another buyer and is dedicated to your part number only.

8. What thread sizes and standards do you support for brass inserts?

We manufacture inserts with metric threads following ISO standards, as well as UNC and UNF inch threads for USA and UK market parts. Blind threads and through threads are both available. Thread class is controlled to standard tolerances during production. If your drawing specifies a thread class, we manufacture to that standard. Non-standard thread forms or custom pitches are evaluated on a case-by-case basis, share your drawing and we will confirm feasibility before quoting.

Request a Brass Inserts Quote

To request a brass insert quotation, send your drawing and RFQ details.

Please include:

• Material specification
• Quantity requirement (one-time, repeat, or blanket order)
• Critical dimensions and tolerance requirements
• Required delivery timeline
• Shipping terms (EXW, DAP, or DDP)

Send your RFQ and drawings to receive a quotation with pricing and indicative lead time.