Printed fasteners
Heat-set inserts, embedded nuts, hole tolerances
Brass heat-set inserts
| Thread | Ø outer | Hole | Boss |
|---|---|---|---|
| M3 | 4.6 мм | 4.2 мм | ≥8.4 мм |
| M4 | 6.3 мм | 5.6 мм | ≥11.2 мм |
| M5 | 7.1 мм | 6.4 мм | ≥12.8 мм |
| M6 | 8.7 мм | 8 мм | ≥16 мм |
Rules
- •Hole for brass insert = outer Ø minus 0.3–0.5 mm (heat-set)
- •Boss around insert ≥1.5×insert Ø — else the wall cracks
- •Install with a soldering iron at 250–300°C, keep it straight
- •Self-tap hole: Ø = screw − 2×layer height
- •Embedded nuts: pocket = nut +0.2–0.3 mm, anti-rotation stop
Heat-set inserts are the most reliable threaded joint for 3D printing: they survive dozens of disassemblies. A pause-embedded nut is a free alternative but weaker on pull-out. Self-tapping screws in plastic work only in unloaded spots.