# How to 3D print bolts and nuts that fit

Bolt & Nut Generator guide · NabiMakes Tools · Updated 3 November 2026 · https://nabimakes.com/tools/bolt-and-nut-generator/guide/

Bolt & Nut Generator makes a printable bolt and its nut, M2 to M24 or #2 to 1 inch, coarse or fine. It sizes the thread for a printed mate, a steel nut or a steel bolt, and its thread test prints five nuts so you can find the clearance your printer needs. It is free and downloads STL or 3MF.

[Open Bolt & Nut Generator](https://nabimakes.com/tools/bolt-and-nut-generator/)

## What can you make with Bolt & Nut Generator?

Bolts and nuts from M2 to M24 and #2 to 1 inch, and custom threads. Makers print:

- A replacement bolt and nut when the hardware store is closed.
- A 1/4"-20 tripod screw with a thumb head for a camera mount.
- A thumb nut for a steel bolt, turned by hand without a spanner.
- Plastic hardware where metal would scratch, rust or conduct.
- A thread test to tune the fit of every printed thread on a printer.

## How do you make a bolt and nut, step by step?

Everything is in the panel beside the bolt, which updates as you change it. Start from a preset, then change what you need.

### 1. Start from a preset

Pick a ready-made bolt: M8 × 30 with its nut, a tripod screw, a thumb nut for steel, a long M12 printed lying, a small cap screw or the thread test. A preset sets only what it names, so your clearance stays.

![Bolt & Nut Generator: the presets above the settings, beside the bolt and nut on the print bed.](https://nabimakes.com/tools/assets/preset.light-DFPLsCZS.webp)

### 2. Choose the thread

Metric or inch, the size and its coarse or fine pitch, or a custom diameter and pitch; the length under the head, and a full thread or a plain shank by ISO 4014.

![The Thread section: system, size, pitch, length and full or part thread.](https://nabimakes.com/tools/assets/thread.light-DCLu7SwN.webp)

### 3. Pick the head and the nut

Hex, socket cap, pan, countersunk, a knurled thumb head or none, with a drive the head takes; then a hex, square or thumb nut, tall if you like, or none.

![The Head and Nut sections: the head, its drive, the nut and Tall nut.](https://nabimakes.com/tools/assets/head.light-MlKvwCDH.webp)

### 4. Find your clearance with the thread test

Print the thread test: a short bolt and five nuts, each a step looser, marked with one to five grooves. Pick the nut that turns on by hand without wobbling as Best nut, and its clearance becomes the bolt's.

![The thread test on the bed: a short bolt and five nuts, with Make set to Thread test.](https://nabimakes.com/tools/assets/fit.light-w7Jh3RX7.webp)

### 5. Check it and download

The checks say whether the thread suits your nozzle and layers, whether it needs supports and whether a long bolt should print lying. Then download 3MF or STL, each part as its own file or together.

![The checks, the print figures and Download · free at the end of the panel.](https://nabimakes.com/tools/assets/download.light-CYp1xv28.webp)

## Which bolts can you start from?

Each example opens in Bolt & Nut Generator as a new design, beside your own.

- **M8 × 30 with nut** (M8 × 30, Hex, ISO nut, Free): A hex bolt with its ISO nut, both printed, standing on its head. [Open in Bolt & Nut Generator](https://nabimakes.com/tools/bolt-and-nut-generator/#design=1.NY1RTgMxDETvMt_eqi1CqnwHuIPZdTcRibNyvBVQ9e4oVHz6zczzHdFaAeOjlZjElsn2mFY1dYnmICwSAr7jpt5zM_CJsIlL7YNW-dT_te0BQv_uoRWMquF5HiT_jM7bZdiyVA118IWw5ZgT-HQ4vxKK2hoJ_HIkRHKVBYzrXgoI6Xkl_RoKz7fhs2YKwvj6F025NxBCSnkf7CqlK6FKjPbm2UIXEOai4mKzgo-HMz0TMPbN85oCj8fjFw)
- **1/4"-20 tripod screw** (1/4"-20 UNC, Thumb head, Free): A short thumb screw for a camera's tripod socket, a steel nut's thread. [Open in Bolt & Nut Generator](https://nabimakes.com/tools/bolt-and-nut-generator/#design=1.NY5ZbsMwDETvMt-0G6cboEP0DoxNW0IlypCoIAt890Jo-zkPM498wnKOcLjkaAPrMmizYROVwpYLCAsbwz1xlVJDVriJsHPhVDtN_C3_a20GQr1XkwSHpmENsnQUHr00vbx1X-AkJgXuY3x9J-zBZg83jedPQhTdrKcTwXwRXuCwthhB8L_JfEuX7inh2q2aVUDoxx283IZQMwjGMX51tnKsQkhsvV1NJP59OkfhwjoL3Gk8E_YStEvaXsLmDcdx_AA)
- **M6 thumb nut for steel** (M6, Thumb nut, Steel bolt, Free): A knurled nut alone, sized for a steel M6 bolt. [Open in Bolt & Nut Generator](https://nabimakes.com/tools/bolt-and-nut-generator/#design=1.NY5BbsMwDAT_smc6SFsgB_2h_QNjM5ZQSjIoOmgb-O8BW_TIwe4sH_DeFQnXrj5xW6a2-7RKE2PvBsLCzkgP3MVG6Q3phbCxcR1BK3_Kf7vtDsL4Hi4VCVXcyhyk_ETm_RK2wlVcDOlC2IrP-Veo0lbPSG9ngmcTXpBw21VByH9Xlq_oW7mHrPUmIMRkgue9XkFwVv0IcmMdQqjskR0uolO8CMKswsZtFqTz6ZWwWWnh2Dcra3Ycx_EE)
- **M8 thread test** (M8 × 1.25, Five nuts, Free): The short bolt and five nuts that find your printer's clearance. [Open in Bolt & Nut Generator](https://nabimakes.com/tools/bolt-and-nut-generator/#design=1.JYxBbsMwDAT_smc6SFIUCPiH9g-szVhCJcqg6KBt4L8XQo47s5gnorUCxlcrMYktk-0xrWrqEs1BWCQE_MRDvedm4AthE5faB63yrWCE9gCh__bQCkbV8DwPkv-G_7iNUpaqoQ6-EbYccwJfTtd3QlFbI4HfzoRIrrKAcd9LASG9VtKfkfD8GD1rpiDYHi815d5ACCnlc7C7lK6EKjHem2cLXUCYi4qLzQo-n670MmDsm-c1BY7j-Ac)

## Which print settings work best for bolts and nuts?

Bolts print standing on their head, or lying on a flat when they are long; nuts print flat. None needs supports. The layer height is a starting point: the checks name the one that suits the pitch, and the thinnest wall is the one they hold each filament to.

| Filament | Layer height to start | Thinnest wall | Supports | Notes |
| --- | --- | --- | --- | --- |
| PLA | 0.12 mm | 0.8 mm | None | Crisp threads; light duty only, it creeps under load. |
| PETG | 0.12 mm | 0.8 mm | None | Tougher threads; clean the strings off before the first turn. |

## Tips for threads that turn

- Print the thread test once per printer and filament: the clearance it finds suits every thread you print after.
- Thin layers make better threads: the checks warn when a layer is thicker than a sixth of the pitch.
- A coarse pitch prints better than a fine one at the same size.
- Long bolts print stronger lying on their flat: the layers then run along the bolt.
- Before you print, check it on the view's bar: Dimensions shows its size, Measure the distance between two points, Section cuts it open and Layers steps through it as your printer will.

## What if the nut will not turn or wobbles?

- **The nut will not turn on.** Raise the clearance by 0.05 to 0.1 mm and print both parts again (with a printed mate each takes half of it), or print the thread test and pick the nut that turns by hand.
- **The nut wobbles on the bolt.** Lower the clearance and print both parts again, or pick a tighter nut from the thread test.
- **A printed nut does not fit a steel bolt.** Choose Steel bolt under Mates with: the nut then takes the whole clearance and your printer's measured hole offset.
- **The thread looks rough or melted.** Print thinner layers and a little slower; for a very fine pitch, choose the coarse pitch of the same size.

## Is Bolt & Nut Generator free?

Yes. Every size, head and download is free; downloading needs a free NabiMakes account, which also keeps your projects.

Free:

- Metric and inch threads, coarse, fine and custom
- Every head, drive and nut
- The thread test
- 3MF and STL

## Every setting, with its range and default

Lengths are in millimetres. Each setting shows only where it applies: no head for a nut alone, Best nut only in the thread test.

| Setting | Range | Default | What it does |
| --- | --- | --- | --- |
| **Make** | | | |
| Make | Bolt and nut, Thread test | Bolt and nut | A bolt and its nut, or the thread test. |
| Best nut | The five test nuts | Nut 3 · 0.2 mm | In the thread test: the nut that turned on by hand without wobbling; its clearance becomes the bolt's. |
| **Thread** | | | |
| System | Metric, Inch | Metric | Metric (ISO) or inch (UNC, UNF). |
| Size | M2 to M24, #2 to 1 inch, Custom | M8 | From the size tables, or Custom. |
| Pitch | 1.25 mm · coarse, 1 mm · fine | 1.25 mm · coarse | The size's coarse pitch or one of its fine pitches. |
| Diameter | 2–25.4 mm | 8 mm | A custom thread's diameter. |
| Pitch | 0.35–3.2 mm | 1.25 mm | A custom thread's pitch. |
| Length | 4–100 mm | 30 mm | Under the head. |
| Thread | Full length, Part (ISO 2d + 6) | Full length | Threaded to the head, or a plain shank by ISO 4014. |
| **Head** | | | |
| Head | Hex, Socket cap, Pan, Countersunk, Thumb (knurled), None (set screw) | Hex | The head's shape; none makes a set screw. |
| Drive | Wrench, hex key, Torx, Phillips, slotted, by head | External hex (wrench) | A drive the head takes; picking a head picks one it takes. |
| **Nut** | | | |
| Nut | Hex · ISO 4032 · 13 mm, Hex · DIN 934 · 13 mm, Square, Thumb (knurled), None | Hex · ISO 4032 · 13 mm | The nut's shape, or none. |
| Tall nut | On, off | Off | A nut 1.5 diameters high. |
| **Fit** | | | |
| Mates with | Printed, Steel nut, Steel bolt | Printed | What the printed part screws into. |
| Clearance | 0–0.6 mm | 0.2 mm | The radial play between the threads. |
| **Print** | | | |
| Bolt prints | Upright, Lying | Upright | Standing on its head, or lying on a flat. |