Ready STL files. No customizer, no generator, no waiting for a render.

Eighty three screws, eleven nuts and eleven washers covering M3, M4, M5, M6, M8, M10, M12, M14, M16, M20 and M24. Pick the file, slice it, print it. The name tells you what it is: M8_30mm is an M8 screw, 30 mm long.

These fit real metal hardware

Most printed fastener sets only fit themselves. To print cleanly they thicken the thread root, and a thickened root will not enter a real nut.

This one was measured on the solid, sampling 24 angles around the shank:

• Major diameter 7.866 mm on M8, against the 8.000 limit
• Root diameter 6.436 mm, against the 6.647 minor diameter of a real M8 nut

Both inside tolerance. Which means all four combinations work: printed screw in printed nut, printed screw in metal nut, and metal screw in printed nut.

The thread is modelled to the ISO profile with 6g tolerance, not drawn by hand and not approximated with arcs.

Standards

Screws follow ISO 4017, nuts ISO 4032, washers ISO 7089. Widths across flats, head heights and washer diameters come from the published tables and were checked again on the finished solids.

Worth knowing: the M10 and M12 widths across flats here are 16 and 18 mm, not 17 and 19. Those older figures are DIN, superseded by ISO and no longer what you buy.

What is included

Screws, fully threaded, hex head, in the lengths people actually use:

• M3 · 8 to 30 mm, 7 lengths
• M4 · 8 to 40 mm, 8 lengths
• M5 · 10 to 50 mm, 8 lengths
• M6 · 10 to 60 mm, 9 lengths
• M8 · 12 to 70 mm, 9 lengths
• M10 · 16 to 80 mm, 9 lengths
• M12 · 20 to 80 mm, 8 lengths
• M14 · 25 to 80 mm, 7 lengths
• M16 · 25 to 100 mm, 7 lengths
• M20 · 30 to 100 mm, 6 lengths
• M24 · 40 to 100 mm, 5 lengths

Nuts and washers in all eleven sizes.

Printing

Layer height is the whole game. A thread is a helix, and the number of layers per pitch decides whether the flank comes out smooth or as a staircase.

An M3 has a 0.5 mm pitch. At 0.20 mm that is two and a half layers per thread, which is a groove, not a thread. At 0.08 mm it is six, and it screws in.

Two profiles are included: 0.08 mm for M3 to M6, and 0.12 mm from M8 up where the coarser pitch gives you the layers anyway.

Print them standing, head down on the plate. No supports needed in that orientation.

Set elephant foot compensation to 0.15 mm. First layer spread makes the first two threads fatter than the rest, and that is the most common reason a printed screw jams on the first turn.

Turn ironing off. It smears material onto the thread flanks.

Calibrate once

Print M8_30mm and nut_M8 and thread them together. Smooth with a trace of resistance means you are done for the whole set. If they bind, raise hole compensation by 0.05. If they are sloppy, lower it.

Honest notes

Printed threads are not steel threads. They hold in tension far less, and they will strip if you torque them like metal. Use them for jigs, prototypes, light assemblies, models and places where a metal screw would be overkill or would corrode.

M3 is the practical floor. Below that the pitch drops under half a millimetre and no FDM printer resolves it.

Avoid carbon filled filaments here. They are stiffer but the threads become brittle and strip on the first tighten.