Beyond thermoplastic over-moulding, these inserts are widely used as cast-in / mould-in inserts encapsulated in epoxy cast-resin and SMC/BMC composite parts — the brass terminals and threaded inserts moulded into HV/MV insulators, bushings, instrument transformers, switch rods and standoff insulators. For these thermoset applications we machine anti-rotation knurling, pull-out grooves and sealed or blind bores that keep resin out of the threads during casting, in CW614N / CW617N brass with tin or nickel plating to spec. Supplied to cast-resin and composite-insulator manufacturers serving energy distribution, rail and industrial equipment. Switchgear components →
| Thread d₁ | d₂ H11 pre-bore | d₃ h12 body OD | d₆ h11 knurl OD |
l₁ h12 A / B | l₂ h12 C / D | a₁ knurl pitch | b₁ knurl ht |
s hex AF | e hex diag |
|---|---|---|---|---|---|---|---|---|---|
| M2 | 1.60 | 3.2 | 3.5 | 2.3 | 3.5 | 0.8 | 0.8 | — | — |
| M2.5 | 2.05 | 3.4 | 3.8 | 2.6 | 4.0 | 0.9 | 0.8 | — | — |
| M3 | 2.50 | 3.8 | 4.2 | 3.0 | 4.5 | 0.9 | 1.2 | 5.0 | 5.8 |
| (M3.5) | 2.90 | 4.5 | 5.0 | 3.5 | 5.5 | 1.0 | 1.4 | 5.5 | 6.35 |
| M4 | 3.30 | 5.0 | 5.5 | 4.0 | 6.0 | 1.2 | 1.4 | 6.0 | 6.9 |
| M5 | 4.20 | 6.4 | 7.0 | 5.0 | 7.5 | 1.6 | 1.8 | 7.0 | 8.1 |
| M6 | 5.00 | 7.4 | 8.0 | 6.0 | 9.0 | 1.8 | 2.4 | 9.0 | 10.4 |
| M8 | 6.80 | 10.4 | 10.0 | 8.0 | 12.0 | 2.0 | 4.0 | 11.0 | 12.7 |
| M10 | 8.50 | 13.0 | 12.5 | 10.0 | 15.0 | 3.0 | 4.0 | 14.0 | 16.2 |
| M12 | 10.30 | 17.0 | 16.0 | 12.0 | 18.0 | 3.5 | 5.0 | 19.0 | 21.9 |
| Thread d₁ | d₂ H11 pre-bore | d₃ h12 body OD | d₆ h11 knurl OD |
d₇ collar Ø | f +0.2 collar depth | l₁ h14 E/F body | l₂ h14 G/H body |
l₃ h12 E/F total | l₄ h12 G/H total | s hex AF |
|---|---|---|---|---|---|---|---|---|---|---|
| M2 | 1.60 | 3.2 | 3.5 | — | 0.32 | 2.3 | 3.5 | 3.1 | 4.3 | — |
| M2.5 | 2.05 | 3.4 | 3.8 | — | 0.32 | 2.6 | 4.0 | 3.4 | 4.8 | — |
| M3 | 2.50 | 3.8 | 4.2 | 4.2 | 0.32 | 3.0 | 4.5 | 3.8 | 5.3 | 5.0 |
| (M3.5) | 2.90 | 4.5 | 5.0 | 5.5 | 0.50 | 3.5 | 5.5 | 4.5 | 6.5 | 5.5 |
| M4 | 3.30 | 5.0 | 5.5 | 6.0 | 0.50 | 4.0 | 6.0 | 5.0 | 7.0 | 6.0 |
| M5 | 4.20 | 6.4 | 7.0 | 7.0 | 0.50 | 5.0 | 7.5 | 6.0 | 8.5 | 7.0 |
| M6 | 5.00 | 7.4 | 8.0 | 9.0 | 0.50 | 6.0 | 9.0 | 7.0 | 10.0 | 9.0 |
| M8 | 6.80 | 10.4 | 10.0 | 11.0 | 0.80 | 8.0 | 12.0 | 9.5 | 13.5 | 11.0 |
| M10 | 8.50 | 13.0 | 12.5 | 14.0 | 0.80 | 10.0 | 15.0 | 11.5 | 16.5 | 14.0 |
| M12 | 10.30 | 17.0 | 16.0 | 19.0 | 0.80 | 11.0 | 17.0 | 13.5 | 19.5 | 19.0 |
| Thread d₁ | d₂ H11 pre-bore | d₃ h12 body OD | d₆ h11 knurl OD |
d₇ slot bore | f +0.2 slot depth | l₁ h14 P/Q body | l₂ h14 R/S body |
l₃ h12 P/Q total | l₄ h12 R/S total | s hex AF |
|---|---|---|---|---|---|---|---|---|---|---|
| M2 | 1.60 | 3.2 | 3.5 | 2.5 | 0.4 | 2.3 | 3.5 | 4.0 | 5.2 | — |
| M2.5 | 2.05 | 3.4 | 3.8 | 2.5 | 0.4 | 2.6 | 4.0 | 4.6 | 6.0 | — |
| M3 | 2.50 | 3.8 | 4.2 | 2.8 | 0.5 | 3.0 | 4.5 | 5.5 | 7.0 | 5.0 |
| (M3.5) | 2.90 | 4.5 | 5.0 | 3.5 | 0.5 | 3.5 | 5.5 | 6.0 | 8.0 | 5.5 |
| M4 | 3.30 | 5.0 | 5.5 | 4.0 | 0.5 | 4.0 | 6.0 | 7.0 | 9.0 | 6.0 |
| M5 | 4.20 | 6.4 | 7.0 | 5.0 | 0.5 | 5.0 | 7.5 | 8.3 | 10.8 | 7.0 |
| M6 | 5.00 | 7.4 | 8.0 | 6.0 | 0.5 | 6.0 | 9.0 | 9.8 | 12.8 | 9.0 |
| M8 | 6.80 | 10.4 | 10.0 | 7.0 | 0.8 | 8.0 | 12.0 | 12.6 | 16.6 | 11.0 |
| M10 | 8.50 | 13.0 | 12.5 | 10.0 | 0.8 | 10.0 | 15.0 | 15.0 | 20.0 | 14.0 |
| M12 | 10.30 | 17.0 | 16.0 | 12.0 | 1.0 | 12.0 | 18.0 | 17.8 | 23.8 | 19.0 |
| Thread d₁ | d₂ H11 pre-bore | d₃ h12 body OD | d₆ h11 knurl OD |
d₇ base bore | f +0.2 base collar | l₁ h14 Form T | l₂ h14 Form U |
l₃ h12 T total | l₄ h12 U total |
|---|---|---|---|---|---|---|---|---|---|
| M2 | 1.60 | 3.2 | 4.5 | 3.4 | 0.4 | 3.5 | — | 5.2 | — |
| M2.5 | 2.05 | 3.5 | 5.0 | 3.6 | 0.4 | 4.0 | — | 6.0 | — |
| M3 | 2.50 | 4.0 | 5.5 | 3.8 | 0.5 | 4.5 | — | 7.0 | — |
| (M3.5) | 2.90 | 4.6 | 6.0 | 4.5 | 0.5 | 5.5 | — | 8.0 | — |
| M4 | 3.30 | 5.3 | 7.0 | 5.0 | 0.5 | 6.0 | 8.0 | 9.0 | 11.0 |
| M5 | 4.20 | 6.6 | 9.0 | 6.0 | 0.5 | 7.5 | 10.0 | 10.5 | 13.3 |
| M6 | 5.00 | 7.8 | 10.0 | 7.0 | 0.5 | 9.0 | 12.0 | 12.8 | 15.8 |
| M8 | 6.80 | 10.5 | 12.0 | 9.0 | 0.8 | — | 16.0 | — | 20.6 |
| M10 | 8.50 | 13.0 | 15.0 | 12.0 | 0.8 | — | 20.0 | — | 25.0 |
| M12 | 10.30 | 15.7 | 18.0 | 15.0 | 1.0 | — | 24.0 | — | 29.8 |
| M16 | 14.10 | 21.0 | 24.0 | 19.0 | 1.2 | — | 32.0 | — | 39.5 |
DIN 16903 is the German standard for open-type brass inserts designed to be placed in the mould tool and over-moulded during injection moulding. The plastic flows around the knurls and undercuts as it solidifies, giving the highest pull-out and torque retention of any insert type. Brassland manufactures all 14 standard forms — A, B, C, D, E, F, G, H, P, Q, R, S, T and U.
Headed forms resist push-through where the screw clamps from the opposite side; unheaded forms suit blind bosses. Through-hole versions let the screw pass completely; closed (blind) versions seal the thread from resin ingress during moulding. The DIN 16903 form letter defines the combination — send your boss design and we’ll confirm the right form.
Standard coverage runs M2 to M16 ISO metric and #4-40 to ½-13 UNC. Inserts are machined from CW614N (CuZn39Pb3) brass per EN 12164, RoHS and REACH compliant, with diamond or straight knurls to DIN 82.
Yes — because the insert is over-moulded rather than installed afterwards, DIN 16903 inserts work in any moulding compound, including glass-filled thermoplastics and thermosets that are too hard for heat-set or self-tapping installation. All production is made to order and confirmed within one business day.
There is no strict minimum order quantity. First orders typically start from around 1,000 pieces per form and thread size, which is where bar setup and knurling tooling become economical, and the same process scales to high-volume OEM schedules. Prototypes and pre-production samples can be machined ahead of the production batch so the insert can be trialled in your mould before a full release.
Quotations are typically returned within 24 hours once we have the DIN 16903 form letter, thread size, knurl type, alloy and quantity. Production lead time is 3 to 5 weeks from an approved drawing or approved sample; prototypes and samples are shorter, and repeat schedules are planned against your release forecast.
Yes. Every Brassland insert is machined to order, so a non-standard body diameter, knurl pattern, blind bore, flange or length is simply another print to run on the same Swiss-type lathes. Send the drawing with your boss design and annual volume. The same parts can be quoted in CW617N, C36000 or lead-free CW724R / C69300 where the programme calls for a different alloy.
Each shipment carries an EN 10204 3.1 mill certificate (3.2 on request), a Certificate of Conformity and a dimensional inspection report against the approved drawing. Brassland is certified to ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 by DQS, and parts are RoHS and REACH compliant with SVHC disclosure on request. We ship on Incoterms 2020 DDP, FOB or CIF, with EXW or DAP on request, through Mundra, Pipavav, Kandla and Nhava Sheva under HS codes 7415, 7412 and 7419, to customers in more than 40 countries.
Brassland manufactures to the published EN, ISO and ASTM specifications below. Mill certificates per EN 10204 Type 3.1 are supplied as standard; Type 3.2 (third-party witnessed) available on request. Open any link to verify the standard directly with the publishing body.
Last reviewed: June 2026. All Brassland products are made to order — please confirm grade, surface finish, plating and packaging requirements at quotation stage. Standards listed above are referenced; production lots are released against the EN 10204 Type 3.1 inspection certificate accompanying each shipment.