--- title: "Heat-Set Threaded Inserts for Plastic" description: "Heat-Set Threaded Inserts for Plastic to Trade series (heat-set insert): sizes M2 to M6, od 3.2-8.2 mm, long 3-9.5 mm. Technical drawing redraws to any row." url: https://engineeringhardware.com/fastener/heat-set-threaded-inserts/ source: Engineering Hardware & Fasteners --- # Heat-Set Threaded Inserts for Plastic Threaded Inserts · Heat-Set & Molded-In Inserts 7 catalogued sizes, dimensioned to Trade series (heat-set insert). Pick any row and the technical drawing redraws to it. Heat-Set Threaded Inserts for Plastic to Trade series (heat-set insert) are catalogued in sizes M2 to M6, with od 3.2-8.2 mm, long 3-9.5 mm. 7 sizes are held in the table below, and the technical drawing redraws to whichever row you select. - **Standard:** Trade series (heat-set insert) - **Size range:** M2-M6 - **OD:** 3.2-8.2 mm - **Long:** 3-9.5 mm - **Catalogued sizes:** 7 Dimensions are nominal values from the governing standard. Confirm the tolerance class for your application before ordering. ![Heat-Set Threaded Inserts for Plastic technical product image](https://engineeringhardware.com/wp-content/uploads/2026/09/Heat-Set-Inserts.webp) Product catalog ## Related Heat-Set & Molded-In Inserts products [![OEM Brass Insert for Plastic M3 Flange Double Knurled Brass Insert Nut M2 Plastic M3 Flange](https://img.engineeringhardware.com/OEM-Brass-Insert-for-Plastic-M3-Flange-Double-Knurled-Brass-Insert-Nut-M2-Plastic-M3-Flange.webp)](https://engineeringhardware.com/product/oem-brass-insert-for-plastic-m3-flange-double-knurled-brass-insert-nut-m2-plastic-m3/) Heat-Set, Knurled & Molded-In Inserts ### [OEM Brass Insert for Plastic M3 Flange Double Knurled Brass Insert Nut M2 Plastic M3 Flange](https://engineeringhardware.com/product/oem-brass-insert-for-plastic-m3-flange-double-knurled-brass-insert-nut-m2-plastic-m3/) Round Head · DIN, ANSI, GB, JIS **US$0.60**MOQ 1,000 pieces [![Carbon Steel Nickel Plated Insert Clinch Nut for Equipment Frames with M4 GB Standard Knurled Ring](https://img.engineeringhardware.com/Carbon-Steel-Nickel-Plated-Insert-Clinch-Nut-for-Equipment-Frames-with-M4-GB-Standard-Knurled-Ring.webp)](https://engineeringhardware.com/product/carbon-steel-nickel-plated-insert-clinch-nut-for-equipment-frames-with-m4-gb/) Heat-Set, Knurled & Molded-In Inserts ### [Carbon Steel Nickel Plated Insert Clinch Nut for Equipment Frames with M4 GB Standard Knurled Ring](https://engineeringhardware.com/product/carbon-steel-nickel-plated-insert-clinch-nut-for-equipment-frames-with-m4-gb/) Clinch Nut · DIN, ANSI, GB, JIS, GOST, BSW **US$0.012 – 2.50**MOQ 10 bags [![Custom Threaded Insert for Automotive Brass Heat Set Knurled Nut OEM ODM Drawing M3 M4 M5 Injection Molded Housing](https://img.engineeringhardware.com/Custom-Threaded-Insert-for-Automotive-Brass-Heat-Set-Knurled-Nut-OEM-ODM-Drawing-M3-M4-M5-Injection-Molded-Housing.webp)](https://engineeringhardware.com/product/custom-threaded-insert-for-automotive-brass-heat-set-knurled-nut-oem-odm-drawing-m3/) Heat-Set, Knurled & Molded-In Inserts ### [Custom Threaded Insert for Automotive Brass Heat Set Knurled Nut OEM ODM Drawing M3 M4 M5 Injection Molded Housing](https://engineeringhardware.com/product/custom-threaded-insert-for-automotive-brass-heat-set-knurled-nut-oem-odm-drawing-m3/) Metric thread inserts · OEM,ODM **US$0.024 – 0.096**MOQ 10 pieces [![M2 M3 M4 M5 M6 M8m10 Female Threaded Molded-in Nut Brass Hex Insert for Plastic Injection](https://img.engineeringhardware.com/M2-M3-M4-M5-M6-M8m10-Female-Threaded-Molded-in-Nut-Brass-Hex-Insert-for-Plastic-Injection-2.webp)](https://engineeringhardware.com/product/m2-m3-m4-m5-m6-m8m10-female-threaded-molded-in-nut-brass-hex-insert-for-plastic-2/) Heat-Set, Knurled & Molded-In Inserts ### [M2 M3 M4 M5 M6 M8m10 Female Threaded Molded-in Nut Brass Hex Insert for Plastic Injection](https://engineeringhardware.com/product/m2-m3-m4-m5-m6-m8m10-female-threaded-molded-in-nut-brass-hex-insert-for-plastic-2/) Hexagon Head · DIN, ANSI, GB, JIS, GOST, BSW **US$0.096 – 0.60**MOQ 100,000 pieces [![Custom Double Knurled Head Brass Insert Nut Brass Decorative Nut Heavy Finish PCS Water](https://img.engineeringhardware.com/Custom-Double-Knurled-Head-Brass-Insert-Nut-Brass-Decorative-Nut-Heavy-Finish-PCS-Water.webp)](https://engineeringhardware.com/product/custom-double-knurled-head-brass-insert-nut-brass-decorative-nut-heavy-finish-pcs/) Heat-Set, Knurled & Molded-In Inserts ### [Custom Double Knurled Head Brass Insert Nut Brass Decorative Nut Heavy Finish PCS Water](https://engineeringhardware.com/product/custom-double-knurled-head-brass-insert-nut-brass-decorative-nut-heavy-finish-pcs/) Round Head · DIN **US$0.06 – 0.60**MOQ 10,000 pieces [![Molded in Blind Threaded Inserts Plastic, Thread Insert 8-32](https://img.engineeringhardware.com/Molded-in-Blind-Threaded-Inserts-Plastic-Thread-Insert-8-32.webp)](https://engineeringhardware.com/product/molded-in-blind-threaded-inserts-plastic-thread-insert-8-32/) Heat-Set, Knurled & Molded-In Inserts ### [Molded in Blind Threaded Inserts Plastic, Thread Insert 8-32](https://engineeringhardware.com/product/molded-in-blind-threaded-inserts-plastic-thread-insert-8-32/) Knurled Nuts · DIN, GB, JIS **US$0.054 – 0.06**MOQ 2,000 pieces [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 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. ![Heat-Set Threaded Inserts for Plastic in use — application photograph](https://engineeringhardware.com/wp-content/uploads/2026/09/Heat-Set-Inserts-Applications.webp) ### 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/) ## Technical Drawing Dimensioned line drawing of M2 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):** 3.2 - **Length L (mm):** 3.0 - **Hole in parent (mm):** 3.0 - **Recommended boss OD (mm):** 6.4 - **Knurl bands:** 2 - **Material:** Brass CuZn39Pb3 - **Installation:** Heated tip, 200-250 u00b0C ## Dimensions & Specifications (Trade series (heat-set insert)) Every row below is a starting point for the customizer above — pick any size and the drawing will redraw to that row. | Thread size | Outer diameter (mm) | Length L (mm) | Hole in parent (mm) | Recommended boss OD (mm) | Knurl bands | Material | Installation | | --- | --- | --- | --- | --- | --- | --- | --- | | [M2](https://engineeringhardware.com/guide/size/m2-heat-set-threaded-inserts/) | 3.2 | 3.0 | 3.0 | 6.4 | 2 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M2.5](https://engineeringhardware.com/guide/size/m2-5-heat-set-threaded-inserts/) | 3.6 | 4.0 | 3.4 | 7.2 | 2 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M3](https://engineeringhardware.com/guide/size/m3-heat-set-threaded-inserts/) | 4.6 | 4.0 | 4.4 | 9.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M3](https://engineeringhardware.com/guide/size/m3-heat-set-threaded-inserts/) | 4.6 | 5.7 | 4.4 | 9.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M4](https://engineeringhardware.com/guide/size/m4-heat-set-threaded-inserts/) | 5.6 | 5.7 | 5.4 | 11.2 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M5](https://engineeringhardware.com/guide/size/m5-heat-set-threaded-inserts/) | 6.9 | 5.8 | 6.7 | 13.8 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | | [M6](https://engineeringhardware.com/guide/size/m6-heat-set-threaded-inserts/) | 8.2 | 9.5 | 8.0 | 16.4 | 3 | Brass CuZn39Pb3 | Heated tip, 200-250 u00b0C | Manufactured to Trade series (heat-set insert), Heat-Set Threaded Inserts for Plastic are threaded inserts supplied by Engineering Hardware. The dimensional data, materials and selection notes are summarized here. ## What Are Heat-Set Threaded Inserts for Plastic? Heat-Set Threaded Inserts for Plastic are threaded inserts defined by Trade series (heat-set insert). They are selected by thread size and the dimensional characteristics shown below, and are available in a range of materials and finishes to suit the application and environment. ## Materials & Finishes Common materials include carbon steel (typically zinc plated or hot-dip galvanized), hardened or case-hardened steel where wear matters, and stainless steel A2 (304) or A4 (316) for corrosion resistance. Specify the material, hardness where relevant, and the surface finish appropriate to your application and environment. ## Pricing Heat-Set Threaded Inserts for Plastic are supplied to order. Pricing starts from approximately US$0.060 per piece for standard sizes in carbon steel; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above. Custom manufacturing · Made to drawing ## Need a heat-set threaded inserts for plastic outside the standard range? 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) 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 ### Which standard governs Heat-Set Threaded Inserts for Plastic? Heat-Set Threaded Inserts for Plastic are manufactured to Trade series (heat-set insert). The dimensional values on this page follow that standard. ### What sizes are available for Heat-Set Threaded Inserts for Plastic? The table on this page lists 7 sizes for Heat-Set Threaded Inserts for Plastic, ranging from M2 to M6. Sizes outside the table can be quoted on request. ### In which materials are Heat-Set Threaded Inserts for Plastic supplied? Heat-Set Threaded Inserts for Plastic are supplied in stainless and phosphor bronze, with finishes including zinc plating, hot-dip galvanizing and black oxide. Choose material and finish to suit the load and the service environment for Heat-Set Threaded Inserts for Plastic. ### How do I request a quotation? Use the parametric drawing on this page to set the exact configuration (size, material, finish) and click "Request this configuration" — a specialist from Engineering Hardware will respond within one business day.