1Heat-set brass
The knurled brass bites into melted plastic and locks in as it cools. It works with plastics such as ABS, PLA, PP and PETG.
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- 400-piece brass heat-set insert kit, M2–M5
Real threads in plastic-12%CODEcapitalone12Harfington 400-piece brass heat-set insert kit, M2–M5
Four hundred brass inserts that you press into a plastic hole with heat to give it solid metal threads. Sorted from M2 to M5 by length, they let 3D-printed parts and plastic cases take screws again and again.
12%$18.74
Price with code · Harfington · as of 2026-10-09Code capitalone12 · 12% off
2Sorted by size
M2 and M3 come in 4, 6, 8 and 10 mm, 30 each; M4 has 30 each of 4 and 6 mm plus 20 each of 8 and 10 mm; M5 has 20 each of 6, 8 and 10 mm.
3From 3D prints to housings
Suited to 3D printer parts, electronics housings, injection-molded parts and toys, anywhere screws come in and out often.
Key specs
- Pieces
- 400
- Material
- Brass
- Sizes
- M2, M3, M4, M5
- Outer diameter
- M2 3.5 mm / M3 5 mm / M4 6 mm / M5 7 mm
- Lengths
- 4 / 6 / 8 / 10 mm
Good pick if
- You assemble 3D-printed parts with screws
- Screw holes in your plastic cases keep stripping
Think twice if
- You have no heat tool such as a soldering iron (they install with heat)
FAQ
Is there a promo code?
Yes. Enter capitalone12 at Harfington checkout when buying the Harfington 400-piece brass heat-set insert kit, M2–M5 for 12% off.
Which plastics does it work with?
The page names plastic housings and 3D prints in materials such as ABS, PLA, PP and PETG.
Can I return it?
The product page offers 30-day returns from delivery. Returns are free within the US; elsewhere you pay the return shipping.
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