Kadrick M2/M3/M4/M5 Threaded Inserts Kit (520 Pcs)
Overview
An assortment box of brass knurled heat-set threaded inserts, sized M2 through M5. These aren’t fasteners themselves — they’re press/heat-inserted into a drilled or 3D-printed plastic hole (using a soldering iron tip or a dedicated heat-insert tool) to leave a permanent metal internal thread behind, so a matching machine screw can be driven in and removed repeatedly without stripping the plastic. Directly relevant to this workspace once any build moves from “components on a breadboard” to a 3D-printed or drilled enclosure — pairs naturally with the Fgruh hex bolt kit also in this library.
Key specs
- Material: brass, knurled exterior (per box copy — “corrosion-resistant brass with precision knurling”)
- Sizes and counts (H = insert height/length):
| Size × H | Qty |
|---|---|
| M2 × 2mm | 80 |
| M2 × 3mm | 60 |
| M2 × 4mm | 60 |
| M3 × 3mm | 50 |
| M3 × 4mm | 50 |
| M3 × 5mm | 50 |
| M3 × 6mm | 40 |
| M3 × 8mm | 40 |
| M4 × 8mm | 30 |
| M4 × 10mm | 25 |
| M5 × 10mm | 20 |
| M5 × 12mm | 15 |
- Thread pitch / outer diameters (printed on box, Φd₁ = insert outer diameter, Φd₂ = pilot-hole diameter):
| Size | Thread pitch | Φd₁ (insert OD) | Φd₂ (pilot hole) |
|---|---|---|---|
| M2 | 0.4mm | 3.0mm | 2.7mm |
| M3 | 0.5mm | 4.5mm | 3.9mm |
| M4 | 0.7mm | 5.5mm | 5.0mm |
| M5 | 0.8mm | 7.0mm | 6.1mm |
- RoHS compliant, cadmium-free (per box markings)
- Not suitable for children under 5 (small-parts warning, per box)
Pinout
N/A — passive mechanical hardware, not an electronic component.
Wiring / typical usage
Drill or print a pilot hole at the Φd₂ diameter for the target size, then press the insert in with a heated soldering iron tip (or a dedicated heat-set insert tool) until it sits flush — the heat softens the surrounding plastic just enough for the knurled exterior to bite in as it cools. Once seated, a matching machine screw (e.g. from the Fgruh kit) threads directly into the brass insert. Useful for any enclosure/mounting design where a screw needs to be removed and reinstalled more than once — bare 3D-printed plastic threads strip after a handful of cycles, these don’t.
Code / libraries
N/A — passive hardware.
Source material
- Full spec table (sizes, counts, thread pitch, diameters) read directly from the box’s own printed label — high confidence, no external source needed.
- Comparable listing for cross-reference: Kadrick 520Pcs M2 M3 M4 M5 Threaded Inserts Assortment Kit — ibspot.com
- Product photo:
/inventory/kadrick-threaded-inserts-kit/product-photo.jpg— the as-supplied photo of the box’s own label doubles as a clean product photo (well-lit, in focus, full spec table legible); no separate manufacturer photo needed.
Verification
Read directly from the box's own printed label (photo-verified) — high confidence. Cross-referenced against a third-party retail listing for the same kit, which lists the identical size/count breakdown.
Notes / gotchas
- H (insert height) is not the same as thread length capacity in the plastic — a taller insert needs a proportionally deeper pilot hole/wall thickness to seat fully.
- Φd₂ is the pilot hole diameter to drill/print, not the insert’s own bore (which matches its thread size, e.g. M3 = 3mm internal thread once seated).
- Don’t overheat during insertion — too much heat can deform the surrounding plastic wall or cause the insert to sink past flush.