---
title: "M3 Heat-Set Threaded Inserts for Plastic Dimensions"
description: "M3 Heat-Set Threaded Inserts for Plastic: coarse thread pitch 0.5 mm. Full size chart to Trade series (heat-set insert) with tolerances."
url: https://engineeringhardware.com/guide/size/m3-heat-set-threaded-inserts/
source: Engineering Hardware & Fasteners
---

# M3 Heat-Set Threaded Inserts for Plastic Dimensions

Threaded Inserts · Trade series (heat-set insert)

Controlling dimensions to Trade series (heat-set insert), with tolerances and fit.

M3 Heat-Set Threaded Inserts for Plastic dimensions to Trade series (heat-set insert): coarse thread pitch 0.5 mm.

- **Coarse thread pitch:** 0.5 mm

Figures are nominal values from the governing standard. Confirm against the tolerance class for your application before machining or ordering.

![M3 Heat-Set Threaded Inserts for Plastic Dimensions reference image](https://engineeringhardware.com/wp-content/uploads/2026/09/Heat-Set-Inserts.webp)

Dimensional data for M3 Heat-Set Threaded Inserts for Plastic to Trade series (heat-set insert), with the installation notes for this type.

Values are taken from the governing standard rather than from a general machine-thread table, because this type is not selected on one.

## M3 Dimensional Row (Trade series (heat-set insert))

| Thread size | Outer diameter (mm) | Length L (mm) | Hole in parent (mm) | Recommended boss OD (mm) | Knurl bands | Material | Installation |
| --- | --- | --- | --- | --- | --- | --- | --- |
| M3 | 4.6 | 4.0 | 4.4 | 9.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |

Custom manufacturing · Made to drawing

## Need heat-set threaded inserts for plastic in a size this table does not list?

This page covers M3 heat-set threaded inserts for plastic. Thread size, body length, knurl or key form and installation method are all variable against the parent material. Made by tapping or knurling.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

[Custom threaded insert manufacturing](https://engineeringhardware.com/custom/inserts/)[Send a drawing](https://engineeringhardware.com/custom/inserts/#rfq)

## Technical Drawing

Dimensioned line drawing of M3 Heat-Set Threaded Inserts for Plastic to Trade series (heat-set insert). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Outer diameter (mm):** 4.6
- **Length L (mm):** 4.0
- **Hole in parent (mm):** 4.4
- **Recommended boss OD (mm):** 9.2
- **Knurl bands:** 3
- **Material:** Brass CuZn39Pb3
- **Installation:** Heated tip, 200-250 u00b0C

## Dimensions & Specifications (Trade series (heat-set insert))

| Thread size | Outer diameter (mm) | Length L (mm) | Hole in parent (mm) | Recommended boss OD (mm) | Knurl bands | Material | Installation |
| --- | --- | --- | --- | --- | --- | --- | --- |
| M2 | 3.2 | 3.0 | 3.0 | 6.4 | 2 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M2.5 | 3.6 | 4.0 | 3.4 | 7.2 | 2 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M3 | 4.6 | 4.0 | 4.4 | 9.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M3 | 4.6 | 5.7 | 4.4 | 9.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M4 | 5.6 | 5.7 | 5.4 | 11.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M5 | 6.9 | 5.8 | 6.7 | 13.8 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |
| M6 | 8.2 | 9.5 | 8.0 | 16.4 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C |

Product catalog

## Related Heat-Set & Molded-In Inserts products

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Hexagon Head · DIN, ANSI, BSW

**US$0.12 – 12.00**MOQ 50 kpcs

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[View all Heat-Set, Knurled & Molded-In Inserts →](https://engineeringhardware.com/fastener-products/threaded-inserts-clinch-fasteners/heat-set-knurled-molded-in-inserts/) [Full product catalog](https://engineeringhardware.com/products/)

## Applications & Industries for M3 Heat-Set Threaded Inserts for Plastic

The sectors that buy Heat-Set Threaded Inserts for Plastic, and the duty each one buys them for. Stocked from M2 to M6.

### Industries that specify Heat-Set Threaded Inserts for Plastic

- **Consumer electronics:** Housings assembled and re-opened for service.
- **Injection moulding:** Post-moulded threads in bosses.
- **Prototyping & product development:** Real threads in a printed prototype.
- **Additive manufacturing:** Threads in printed parts, where layer adhesion will not hold a screw.
- **Plastics & moulded parts:** Durable metal threads in housings that would strip if screwed into directly.
- **Aluminium & castings:** Reinforced threads in soft alloy, and repair of stripped holes.

### Typical applications

- installed with a heated tip so the plastic flows into the knurl
- boss hole size is the critical dimension, not the insert length
- a reusable metal thread in a plastic or printed boss
- repairing a stripped hole to its original size
- assemblies opened and closed many times over their life
- creating a reusable metal thread in a soft or thin parent

### Service conditions to specify against

- **Marine and coastal:** Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- **Parent material first:** The insert type is chosen by what it goes into — moulded plastic, printed polymer, alloy casting or timber — not by the screw that goes into it.

[Full application guide: where Heat-Set Threaded Inserts for Plastic are used, how to specify them, and the cases they are wrong for](https://engineeringhardware.com/applications/heat-set-threaded-inserts/)

Inside the plant

## Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 01 **Cold heading** Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail. Head dimensions and under-head radius checked at set-up and per shift.
2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 02 **Thread rolling** Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch. Go / no-go ring gauges to ISO 965 tolerance class 6g.
3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 03 **Heat treatment** Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it. Core hardness and tensile tested per lot to ISO 898-1.
4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 04 **Surface treatment** Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list. Coating thickness and neutral salt spray hours to ISO 9227.

## Frequently Asked Questions

### What is the coarse-thread pitch of M3 for Heat-Set Threaded Inserts for Plastic?

For M3 the standard coarse pitch is 0.5 mm — this is the value used for Heat-Set Threaded Inserts for Plastic.

### What clearance and tapping drill suit M3?

Use a 3.4 mm clearance hole (ISO 273 medium) for through-fixing, or a 2.5 mm tapping drill for a coarse M3 thread.

### Is M3 Heat-Set Threaded Inserts for Plastic suitable for electronics and small mechanisms?

M3 Heat-Set Threaded Inserts for Plastic is in the micro range and is widely used in electronics, instrument enclosures and small precision mechanisms. Watch the over-torque margin — micro joints strip easily.

### What's the typical proof load behavior of M3 class 8.8?

Micro-thread joints are sensitive to plastic deformation in the first turn under load — use a torque-limiting driver and check the bearing surface deformation on softer mating materials.

### How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.

## Related Pages

[View the full Heat-Set Threaded Inserts for Plastic page](https://engineeringhardware.com/fastener/heat-set-threaded-inserts/)

### More Heat-Set Threaded Inserts for Plastic Guides