M3 and M4 inserts in a 3D-printed housing? You know the drill—torque it once, feel it shift, lose trust in the whole part. These Jaycar tips stop that before it starts. Heat the tip, press it into your threaded brass insert, and the surrounding thermoplastic flows around the shaft to form a mechanical lock. The thread stays put under load and repeated use. M3 tip length is 16.5 mm; M4 tip is 17.5 mm. Shaft outside diameter 6.5 mm, inside hole 4.75 mm × 25 mm deep, shaft to screw base 28 mm. Assembled length: 44.5 mm (M3) or 45.5 mm (M4). If your build is M3 or M4, this is the tip that keeps the thread honest
