Free 3D bolt and nut generator: metric thread STL

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What this tool does

A real ISO metric thread, from M4 to M60, with each size's standard pitch or the one you choose.

A matching bolt and nut: they come together in one STL, with the clearance your printer needs.

Four heads: hex with the standard wrench size, socket, a knob to tighten by hand, and a headless threaded rod.

Hex or knob nut, with countersunk openings so the bolt starts easily.

Up to 150 mm long, with an optional smooth shank next to the head.

Prints without supports: the bolt standing on its head and the nut lying flat. All in your browser.

How it works

Choose the thread

Diameter and pitch. With the standard pitch, the part screws into hardware store bolts and nuts of the same size.

Define the bolt and the nut

Head, length and smooth shank of the bolt, and the shape of the nut. The wrench sizes show next to them.

Download and print

Get the STL and print it as it comes, without supports. With layers of 0.15 mm or less the thread runs smoother.

Frequently asked questions

Can you 3D print bolts and nuts that work?

Yes. With ilove3d's bolt and nut generator they come with a real metric thread and screw into each other and into metal parts of the same size. From M8 up they print well with a 0.4 mm nozzle; smaller sizes are better with 0.1 mm layers. They are good for holding, adjusting and assembling, not for replacing bolts that carry load or safety.

How much clearance does a printed thread need?

About 0.3 mm between bolt and nut works on most printers, and it is the tool's default. Plastic comes out a little wider than drawn, so a thread with no clearance does not screw in. If they turn hard, raise it to 0.4 or 0.5 mm; if they rattle, lower it.

What is the best way to print a bolt?

Standing on its head, as the file comes: it needs no supports and the thread stays round. Printed this way the layers run across the axis, so it does not take much pulling; for more strength use more perimeters, 100% infill and PETG instead of PLA.

What is the pitch of a thread?

The distance from one thread to the next, in millimeters. Each metric diameter has a standard pitch: 1 mm for M6, 1.25 mm for M8, 1.5 mm for M10. A bolt and a nut only screw together if they share diameter and pitch. For parts that will only be used with each other, a pitch larger than standard gives thicker threads that are easier to print.

Question of the month

Which printer do you use?