3D Printable Screw Generator for Fusion 360 (Optimized Threads)

3D Printable Screw Generator for Fusion 360

This is a fully editable Fusion 360 file designed to generate screws specifically optimized for 3D printing.

Most standard metric threads are designed for metal manufacturing, not for FDM printing.
That means they usually have:

• overly sharp thread profiles

• unsupported overhangs

• tiny fragile tips

• unreliable tolerances

This generator solves those problems by allowing you to fully customize the geometry of the thread depending on:

• your printer

• your material

• your layer height

• your nozzle size

The goal is simple:
Create screws that print reliably and work consistently.

Features

• Fully parametric Fusion 360 file

• Adjustable thread angle

• Adjustable minimum thread section

• Adjustable tolerances

• Automatic nut generation

• Horizontal split screw version for extra strength

• Auto-updating labels and dimensions

• Optimized specifically for FDM printing

• Works great with PLA and PETG

YouTube video

Full explanation and engineering breakdown here:

The video explains:

• how printable threads work

• why standard threads fail

• how to optimize screws for FDM printing

• how to use this generator

• how to create stronger printable screws

Important: How printable threads work

A standard metric thread is usually NOT ideal for 3D printing.

There are 2 major problems:

1. Overhang angle

Very sharp thread angles create unsupported geometry.
Your printer ends up printing partially in the air, which causes sagging and poor precision.

This generator allows you to adjust the thread angle so the screw prints cleanly without supports.

Recommended values:

• 35° → better mechanical performance

• 45° → maximum reliability

2. Tiny sharp thread tips

Standard threads end in extremely small sharp points.

FDM printers have a physical limit regarding the smallest detail they can print reliably.
If the tip is too thin, the thread becomes inconsistent and fragile.

The parameter SECTION_MIN controls the minimum flat section at the tip of the thread.

Recommended values:

• 0.3 mm minimum

• Higher values = easier printing and stronger threads

• Lower values = more compact threads and better mechanical advantage

User parameters

Only the parameters marked with a blue star should be modified.

LARGO

Length of the threaded section.

DIAMETRO_EXT

Outer diameter of the screw.

SECTION_MIN

Minimum flat section at the tip of the thread.

ANGULO

Angle of the thread walls.

TOLERANCIA

Clearance between screw and nut.

Recommended:
0.15 mm

TUERCA

Nut size multiplier.

• 1 = standard nut

• 2 = double-size nut

• etc.

Vertical vs Horizontal Screws

This project includes two versions:

Horizontal split screw (default)

The screw is split in half and designed to be printed horizontally.

This makes the screw significantly stronger because the layer orientation follows the forces applied to the thread.

A centering skeleton is included to align both halves.

Standard vertical screw

If you want the normal vertical version:

Simply go one step back in the Fusion 360 timeline.

The final split operation will disappear and you will get the standard screw version.

Internal hole

The screw includes a central hole.

This may seem counterintuitive, but it actually increases strength on vertically printed screws because it generates additional perimeter walls inside the part.

Most of the strength in FDM prints comes from walls/perimeters, not infill.

Reference cube

The small cube marked with "XZ" is a 20x20 mm calibration cube used only as a scale reference.

This helps visualize the actual size of the screw while designing.

Notes

• This is Version 1 and will probably evolve over time.

• Some parameter combinations may generate Fusion errors.

• The red labels update automatically and may take a few seconds.

• This project is designed mainly for FDM printers.

Feedback / Suggestions

If you have ideas, improvements or find bugs, feel free to leave a comment or contact me:

📩 [email protected]

I will probably continue improving this project over time.