Sample STEP Files: Free STEP and STL Downloads
Here are five free sample STEP files to download: a flange plate, an L-bracket, a keyed shaft, a flanged bushing and an electronics enclosure. Each is one solid in millimetres, saved as STEP AP214, with an STL of the same part beside it for testing a CAD viewer, an import or a CAM setup.
Which sample STEP files can I download?
Five simple machined parts, from a 19 KB bushing to a 95 KB enclosure. Click a STEP or STL link to download the file; the size and features are listed so you can pick the right test case, and every part is drawn above its name.
| Part | Size and features | Download |
|---|---|---|
 Flange plate | 100 × 100 × 10 mm. Ø40 mm centre bore, four Ø9 mm holes on a 76 mm square, R8 corners. Good for hole recognition and drilling in CAM, a first import check. | STEP (54 KB) STL (76 KB) |
 L-bracket | 60 × 40 × 50 mm, 5 mm thick. two legs with two Ø6.6 mm (M6 clearance) holes each, R4 inside corner. Good for a sheet-metal or machined bracket, holes on two faces. | STEP (42 KB) STL (54 KB) |
 Stepped shaft with keyway | Ø25 × 120 mm overall. Ø25 mm shoulder 40 mm long, Ø20 mm journal, 6 × 3.5 × 30 mm keyway, 1 mm chamfers. Good for turned parts, lathe CAM, cylindrical faces. | STEP (44 KB) STL (52 KB) |
 Flanged bushing | Ø45 × 30 mm. Ø45 × 5 mm flange, Ø30 mm body, Ø20 mm through bore, 0.8 mm chamfers. Good for the smallest file here, a quick viewer or upload test. | STEP (19 KB) STL (49 KB) |
 Electronics enclosure | 80 × 60 × 30 mm. open box with 2 mm walls, R5 corners, four Ø7 mm bosses with Ø2.5 mm (M3) pilot holes. Good for a shelled part with thin walls, 3D printing and pocketing. | STEP (95 KB) STL (125 KB) |
What is inside each sample STEP file?
Each file holds one closed solid, written as STEP AP214 in millimetres. The faces are exact geometry, so a hole is a true cylinder and a fillet a true arc; there are no assemblies, colours or drawing views, which keeps every file small and easy to check.
Open a file in a text editor and you will see the plain-text STEP format: a header with the file name, the schema line naming AP214, and numbered entities down to the points and surfaces. For more on the format, see what a STEP file is and AP203 vs AP214.
How do I open a sample STEP file?
Drop it into the free online STEP viewer to see it in your browser, or open it with File, Import in any CAD program. The STL opens in the STL viewer and in every 3D printing slicer.
If the part comes in at the wrong size, check the units: these files are in millimetres, and a correct import of the flange plate measures 100 mm (3.937 in) across. More help is in how to open a STEP file.
What can I test with a sample STEP file?
Anything that has to read a real solid: a CAD import, a viewer or web app you are building, a CAM toolpath or post-processor, a quoting site’s upload, or a converter. Known sizes make it easy to see whether the result is right, not just whether it opened.
- Import and units: the flange plate is 100 mm square with a 40 mm bore; measure both.
- Holes and drilling: the flange plate and L-bracket carry through holes on one and two faces.
- Turning: the stepped shaft has two diameters, chamfers and a keyway for a milling setup.
- Thin walls and printing: the enclosure has 2 mm walls and four bosses with M3 pilot holes.
- Conversion: run a STEP through the STEP to STL converter and compare it with the STL supplied.
Why download both the STEP and the STL?
They are the same part in two kinds of file. The STEP is an exact solid that CAD and CAM can edit and measure; the STL is a triangle mesh, which slicers and many viewers want. Having both lets you compare a tool’s handling of each.
The difference matters when a mesh is all you have: turning an STL back into a solid gives flat facets, not true cylinders. The trade-offs are in STL vs STEP.
Frequently asked questions
Where can I download a sample STEP file?
From this page: five sample STEP files of simple machined parts, each a single solid in millimetres with an STL of the same part beside it. They download directly, with no account and no form.
What units are these STEP files in?
Millimetres. Each file declares millimetres in its header, so a CAD program set to inches converts it on import; a 100 mm plate should come in as 3.937 in. If it comes in 25.4 times too big or too small, the importer ignored the units.
Which STEP version are the files?
AP214 (ISO 10303-214), the version most CAD programs export by default and every common one imports. AP203 and AP242 readers open AP214 files too; see the difference between AP203 and AP214 if a system asks.
Can I use these sample files in my own project?
Yes. They are free to download and use for testing, teaching and demonstrations, including in software you are building. The parts were modelled for this page and contain no one else’s design.
Why is the STL file bigger than the STEP file?
The STL stores every triangle of the surface, so curved faces such as holes and fillets need many triangles. The STEP stores each face once as exact geometry: a hole is one cylinder, not hundreds of flat facets.
Have a drawing but no STEP file?
Upload the drawing to Drawing to STEP: a PDF, PNG or JPG of an engineering drawing becomes a 3D STEP model in minutes, with files from $29.99. Keep the drawing with the model: the STEP carries the shape, and the drawing carries the tolerances and notes.