Free custom STL files and 3D models for 3D printers

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Tube STL file OD 56 mm, ID 50 mm, length 30 mm

Rectangular duct adapter STL 3D file 200x90 mm to 80x80 mm – transition: 60 mm

Round box with lid STL 3D file ⌀ 80 mm - Height: 50 mm, Shell: 3 mm

Rectangular pipe adapter STL 3D file 110x110 mm to 80x80 mm – transition: 20 mm

Pipe clip holder Ø50 mm STL file · Countersunk screw Ø5 mm

Bowl STL 3D file, inner: base Ø70 mm, top Ø120 mm, height 70 mm - wall thickness 6 mm

Pot STL 3D file, inner: base Ø50 mm, top Ø80 mm, height 70 mm - wall thickness 2 mm

Multi-compartment box STL file: 48 compartments of 20×20×20 mm

L-bracket 200×200 mm STL file, thickness 5 mm, hole diameter 6 mm

Protective grid STL 3D file, center-to-center: 70x70mm, mesh: 10mm - Ø4mm

Browse a growing library of free STL files and 3D models — or generate custom parts online to your exact specs.

Featured Model of the Day

Rectangular prism STL 3D file 100×70×29 mm 📦 #755

1 object(s) - format STL

View of object #0

Latest user-generated 3D models

Enclosure with screw-mounted lid STL file: 105×42×180 mm 📦 #11458

2 object(s) - format STL

View of object #0

From the Blog

Why Modeling Strategy Matters in Procedural CAD Modeling

2025-12-14 · 3D Modeling · sylvain

Why does modeling strategy matter so much in procedural CAD? Two scripts can produce the exact same geometry while showing very different generation times.

Using a concrete build123d example, this article explains why certain operations, such as fillets, become expensive when repeated at scale, and how a simple change in approach can drastically reduce computation time.

A clear overview of the key challenges in procedural modeling, highlighting the direct impact of design choices on CAD engine performance.

Read the article

A selection of custom 3D models

📦 Model #3612

1 object(s)

- format STL

Protective grid STL 3D file, center-to-center: 210x110mm, mesh: 10mm - Ø5mm

Download this rectangular protective honeycomb grid model in STL format. Mounting holes are placed at the four corners (center-to-center 210x110 mm), each with a diameter of Ø5 mm. The overall dimensions reach 220x120 mm, with very large 10 mm cell size for peak ventilation. This grid serves as both a protective guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	210	mm
width or center-to-center	110	mm
mesh size	10	mm
dual color	no
holes	yes
hole diameter	5	mm

📦 Model #2614

1 object(s)

- format STL

Mounting bracket 200×200 mm STL file, thickness 8 mm, hole diameter 6 mm

3D file of a mounting bracket with a reinforcing bar in STL format. The dimensions are 200 mm in length, 200 mm in height, 50 mm in width, and 8 mm in thickness. The mounting holes are designed with a diameter of 6 mm. Chamfers are done to the holes to improve the seating of the heads. The reinforcing bar enhances mechanical strength and provides two openings for screwdriver access. No support is needed to print this bracket, printed flat on the build plate.

Parameter	Value	Unit
length	200	mm
height	200	mm
width	50	mm
thickness	8	mm
hole diameter	6	mm
chamfer on the holes	yes

📦 Model #4328

1 object(s)

- format STL

Tube adapter STL file ⌀ 63–58 mm (Length: 70 mm)

Tube fitting ⌀63 mm to ⌀58 mm in STL format. Total length of this reducer is 70 mm. The larger-diameter tube has a thickness of 3 mm and a length of 30 mm. The smaller-diameter tube has a thickness of 2 mm and a length of 30 mm as well. The ends are raw.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	63	mm
side A thickness	3	mm
side B length	30	mm
side B outer diameter	58	mm
side B thickness	2	mm
transition length	10	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #4414

2 object(s)

- format STL

Round box with lid STL 3D file ⌀ 134 mm - Height: 20 mm, Shell: 2 mm

Get this circular box model in 3D STL format. Its diameter is 134 mm and its total height is 20 mm. The wall thickness is 2 mm. A fillet located at the bottom of the box makes it easier to grip objects.

Parameter	Value	Unit
external diameter	134	mm
total height	20	mm
wall thickness	2	mm
fit clearance	0.2	mm
inner bottom fillet	1	mm

📦 Model #1415

1 object(s)

- format STL

Round air vent STL file ∅ 127 mm, slat angle: 45° with central reinforcement

Model of a round air vent for ventilation in STL format. Its male diameter is 127 mm. The slats have an angle of 45° and a low thickness of 1.5 mm. A centered vertical reinforcement strengthens the slats. This ventilation grille has a prominent flange of 20 mm. The overall diameter of the model is 167 mm.

Parameter	Value	Unit
male diameter	127	mm
slat angle	45	°
slat thickness	1.5	mm
flange width	20	mm
central reinforcement	yes

📦 Model #4503

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 125–80 mm (Length: 105 mm)

Straight tube coupler ⌀125 mm to ⌀80 mm in STL format. Total length of this junction is 105 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 40 mm. The ends are raw.

Parameter	Value	Unit
side A length	35	mm
side A outer diameter	125	mm
side A thickness	5	mm
side B length	40	mm
side B outer diameter	80	mm
side B thickness	5	mm
transition length	30	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #4497

1 object(s)

- format STL

Tubing adapter STL 3D file ⌀ 32–19 mm (Length: 65 mm)

Tube fitting ⌀32 mm to ⌀19 mm in STL 3D format. Length of this junction is 65 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 20 mm. The ends are not rounded.

Parameter	Value	Unit
side A length	35	mm
side A outer diameter	32	mm
side A thickness	2	mm
side B length	20	mm
side B outer diameter	19	mm
side B thickness	2	mm
transition length	10	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #3389

1 object(s)

- format STL

Honeycomb grille STL file, center-to-center: 120x120mm, mesh: 5mm - Ø4mm

3D fan guard model as a STL file. Mounting holes are placed at the four corners (center-to-center 120x120 mm), each with a diameter of Ø4 mm. The overall dimensions reach 128x128 mm, with regular 5 mm cell size for balanced airflow and protection. This grid serves as both a protective guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	120	mm
width or center-to-center	120	mm
mesh size	5	mm
dual color	no
holes	yes
hole diameter	4	mm

📦 Model #2450

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 35–18 mm (Length: 26 mm)

Inline tube reducer ⌀35 mm to ⌀18 mm in STL 3D format. Final length of this fitting is 26 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 10 mm, the smaller one of 8 mm. The ends are rounded on the inside to ease the connection.

Parameter	Value	Unit
side A length	10	mm
side A outer diameter	35	mm
side A thickness	3	mm
side B length	8	mm
side B outer diameter	18	mm
side B thickness	3	mm
transition length	8	mm
axis offset	0	mm
ends fillet	fillet on th...

📦 Model #2965

1 object(s)

- format STL

Support bracket 250×150 mm STL 3D file, thickness 10 mm, hole diameter 8 mm

Model of a support bracket reinforced in STL 3D format. The dimensions are 250 mm in length, 150 mm in height, 50 mm in width, and 10 mm in thickness. The mounting holes have a diameter of 8 mm. Chamfers are applied to the holes for a cleaner fit of the screws. The central reinforcement bar reduces bending and includes two passages for fastening. No support is needed to print this bracket, lying flat on the print bed.

Parameter	Value	Unit
length	250	mm
height	150	mm
width	50	mm
thickness	10	mm
hole diameter	8	mm
chamfer on the holes	yes

📦 Model #3502

1 object(s)

- format STL

Protective grid STL 3D file, 60x60mm, mesh: 8mm

Download this 3D square honeycomb grid model in STL format. The overall size is 60x60 mm, with wide 8 mm cell size for optimal air circulation. This type of grid serves both protection and ventilation roles.

Parameter	Value	Unit
length or center-to-center	60	mm
width or center-to-center	60	mm
mesh size	8	mm
dual color	no
holes	no

📦 Model #4447

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 100–79 mm (Length: 240 mm)

Straight tube fitting ⌀100 mm to ⌀79 mm in STL 3D format. Total length of this sleeve is 240 mm. The larger-diameter tube has a thickness of 4 mm and a sleeve length of 100 mm. The smaller-diameter tube has a thickness of 5 mm and a length of 100 mm as well. The axes of the tubes are offset by 11.4 mm. The ends feature an external fillet.

Parameter	Value	Unit
side A length	100	mm
side A outer diameter	100	mm
side A thickness	4	mm
side B length	100	mm
side B outer diameter	79	mm
side B thickness	5	mm
transition length	40	mm
axis offset	11.4	mm
ends fillet	fillet on th...

📦 Model #3349

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀50 mm to 152×45 mm, thickness 3 mm

Download this 3D file in STL format of a round-to-rectangular adapter with an external diameter of ⌀50 mm and a rectangular section with internal dimensions 152×45 mm. The wall thickness is 3 mm and the overall length is 110.3 mm. A chamfer is present on the outside of the cylindrical end.

Parameter	Value	Unit
cylinder outer diameter	50	mm
cylinder inlet length	25	mm
rectangle internal length	152	mm
rectangle internal height	45	mm
rectangle inlet length	25	mm
offset Z	0	mm
offset Y	0	mm
total length	110.3	mm
thickness	3	mm
chamfer	chamfer on t...

📦 Model #1483

1 object(s)

- format STL

Tube adapter STL file ⌀ 200–50 mm (Length: 80 mm)

Tube reducer ⌀200 mm to ⌀50 mm in STL 3D format. Total length of this junction is 80 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 30 mm, the smaller one of 30 mm as well. The ends have no fillet.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	200	mm
side A thickness	3	mm
side B length	30	mm
side B outer diameter	50	mm
side B thickness	3	mm
transition length	20	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #4475

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 40–37 mm (Length: 118 mm)

Straight tube fitting ⌀40 mm to ⌀37 mm in STL format. Total length of this connector is 118 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 38 mm, the smaller one of 40 mm. The ends have a fillet to make tube connection easier.

Parameter	Value	Unit
side A length	38	mm
side A outer diameter	40	mm
side A thickness	5	mm
side B length	40	mm
side B outer diameter	37	mm
side B thickness	5	mm
transition length	40	mm
axis offset	0	mm
ends fillet	fillet on bo...

📦 Model #2390

1 object(s)

- format STL

Round air vent STL 3D file ∅ 115 mm, slat angle: 45°

3D file of a round grille for air circulation in STL format. Its male diameter is 115 mm. The slats have an angle of 45° and a high thickness of 2 mm. This ventilation grille has a collar of 10 mm. The full diameter of this model is 135 mm.

Parameter	Value	Unit
male diameter	115	mm
slat angle	45	°
slat thickness	2	mm
flange width	10	mm
central reinforcement	no

📦 Model #2221

2 object(s)

- format STL

Small parts organizer with 6 drawers 30×30×60 mm STL file, thickness: 3 mm

3D file of a DIY organizer in 3D STL format. This model contains 6 boxes, arranged in 2 rows and 3 columns. Specifically, this means 2 rows of 3 boxes. Each box measures 30 mm wide, 30 mm high, and 60 mm deep. The wall thickness is 3 mm, which makes the structure solid. The total size of the structure are 121.5 x 76 x 69 mm. All the objects in this model were designed to be printed without support generation.

Parameter	Value	Unit
number of rows	2
number of columns	3
inner drawer depth	60	mm
inner drawer width	30	mm
inner drawer height	30	mm
wall thickness	3	mm
removable divider	none

📦 Model #4452

1 object(s)

- format STL

Oval duct transition adapter STL file 100x70 mm to 80x40 mm – transition: 20 mm

Oval pipe adapter provided as a STL 3D file. The internal cross-section on side A is 100x70 mm, while on side B it is 80x40 mm. You get a sleeve of 5 mm on side A and 10 mm on side B. The transition section is 20 mm long, for a final overall length of 35 mm. The shell is relatively thick, with a wall thickness of 4 mm. External chamfers are added at the ends to make it easier to insert the adapter into ducts or hoses.

Parameter	Value	Unit
side A internal width	100	mm
side A internal height	70	mm
sleeve length on side A	5	mm
side B internal width	80	mm
side B internal height	40	mm
sleeve length on side B	10	mm
thickness	4	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

📦 Model #4201

1 object(s)

- format STL

Washer / Flat Gasket STL 3D file ⌀ID: 3.9 mm ⌀OD: 6.9 mm thickness: 4.3 mm

3D model of washer / gasket in STL 3D file format. This part features an inner diameter of ⌀3.9 mm and an outer diameter of ⌀6.9 mm. The total thickness is 4.3 mm. This part has no finish applied.

Parameter	Value	Unit
inner diameter	3.9	mm
outer diameter	6.9	mm
thickness	4.3	mm
finish	none

📦 Model #1869

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀60 mm to 100×45 mm, thickness 2 mm + offset

3D file in STL format of a round-to-rectangular adapter with an outer diameter of ⌀60 mm and a rectangular section with inner dimensions 100×45 mm. The wall thickness is 2 mm and the total length is 90 mm. The adapter has an offset of 15 mm along the Z axis. Chamfers are applied on the outside of the cylindrical end and on the inside of the rectangular end.

Parameter	Value	Unit
cylinder outer diameter	60	mm
cylinder inlet length	30	mm
rectangle internal length	100	mm
rectangle internal height	45	mm
rectangle inlet length	30	mm
offset Z	15	mm
offset Y	0	mm
total length	90	mm
thickness	2	mm
chamfer	chamfers on ...

📦 Model #2604

1 object(s)

- format STL

Pipe elbow STL 3D file 35° ⌀OD: 55 mm ⌀ID: 51 mm thickness: 2 mm

3D file of a tubing elbow with a 35° angle in STL format. This pipe elbow features an external diameter of 55 mm and an internal diameter of 51 mm. This results in a tube thickness of 2 mm. The ends feature fillets to make it easier to assemble.

Parameter	Value	Unit
outer diameter	55	mm
inner diameter	51	mm
angle	35	°
end fillets	yes

📦 Model #3985

2 object(s)

- format STL

Enclosure with screw-mounted lid STL 3D file: 300×180×70 mm (with ventilation on the lid)

Enclosure model with a screwed lid in 3D STL format. The dimensions are 300 mm long by 180 mm wide and 70 mm high. The cover only is 15 mm high. Wall thickness is 3 mm. This enclosure has cooling area on the lid.

Parameter	Value	Unit
length	300	mm
width	180	mm
total height	70	mm
lid height	15	mm
wall thickness	3	mm
screw margin	0	mm
fit clearance	0.1	mm
cooling level	2
cooling zone(s)	cutouts on t...

📦 Model #4476

1 object(s)

- format STL

Tubing adapter STL 3D file ⌀ 40–37 mm (Length: 115 mm)

Tube adapter ⌀40 mm to ⌀37 mm in STL 3D format. Length of this connector is 115 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 40 mm. The ends are rounded to facilitate the connection of the two tubes.

Parameter	Value	Unit
side A length	35	mm
side A outer diameter	40	mm
side A thickness	5	mm
side B length	40	mm
side B outer diameter	37	mm
side B thickness	5	mm
transition length	40	mm
axis offset	0	mm
ends fillet	fillet on bo...

📦 Model #3057

1 object(s)

- format STL

Right-angle bracket 150×150 mm STL 3D file, thickness 6 mm, hole diameter 6 mm

3D file of a mounting bracket with a central reinforcement in STL format. The dimensions are 150 mm in length, 150 mm in height, 14 mm in width, and 6 mm in thickness. The screw holes are designed with a diameter of 6 mm. Chamfers are applied to the holes to improve the seating of the heads. The central reinforcement bar reduces bending and provides two clearances for screwdriver access. No support is needed to print this bracket, printed flat on the build plate.

Parameter	Value	Unit
length	150	mm
height	150	mm
width	14	mm
thickness	6	mm
hole diameter	6	mm
chamfer on the holes	yes

📦 Model #4502

1 object(s)

- format STL

Pipe elbow STL 3D file 45° ⌀OD: 72 mm ⌀ID: 64 mm thickness: 4 mm

Model of an elbow with a 45° angle in STL format. This pipe elbow has an external diameter of 72 mm and an internal diameter of 64 mm. The tube thickness is therefore 4 mm. End fillets make it easier to insert.

Parameter	Value	Unit
outer diameter	72	mm
inner diameter	64	mm
angle	45	°
end fillets	yes

📦 Model #888

1 object(s)

- format STL

U-shaped handle STL file 35×140×20 mm (Center-to-center 120 mm)

Download this STL 3D file of a U-shaped handle. The overall dimensions are 35×140×20 mm. The handle features a square cross-section and a 90-degree transition. The openings are 6 mm diameter and have a 120 mm center-to-center distance.

Parameter	Value	Unit
width	35	mm
length	140	mm
thickness	20	mm
shape (0:square,1:circle)	0
transition (0:right,1:rounded)	0
fillet radius	0	mm
hole diameter	6	mm

📦 Model #1943

2 object(s)

- format STL

Enclosure with screw-mounted lid STL file: 100×65×50 mm (with ventilation on the lid and under the enclosure)

Enclosure with lid in STL format. The dimensions are 100 mm long by 65 mm wide and 50 mm high. The lid is 10 mm high. Side thickness is 2 mm. This enclosure features marked cooling area on the lid and under the base.

Parameter	Value	Unit
length	100	mm
width	65	mm
total height	50	mm
lid height	10	mm
wall thickness	2	mm
screw margin	0	mm
fit clearance	0.2	mm
cooling level	8
cooling zone(s)	cutouts on b...

📦 Model #4396

1 object(s)

- format STL

Honeycomb grid STL file, 250x250mm, mesh: 10mm

Square grid model as a STL file. The overall size is 250x250 mm, with very large 10 mm cell size for maximum airflow. This grid serves as both a protective guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	250	mm
width or center-to-center	250	mm
mesh size	10	mm
dual color	no
holes	no

📦 Model #3491

1 object(s)

- format STL

Protective grid STL file, center-to-center: 107x107mm, mesh: 10mm - Ø5mm

3D square protective honeycomb grid model as a STL file. Mounting holes are placed at the four corners (center-to-center 107x107 mm), each with a diameter of Ø5 mm. The overall dimensions reach 117x117 mm, with very large 10 mm cell size for maximum airflow. This grid serves as both a protective guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	107	mm
width or center-to-center	107	mm
mesh size	10	mm
dual color	no
holes	yes
hole diameter	5	mm

📦 Model #3364

1 object(s)

- format STL

Honeycomb grid STL file, center-to-center: 92x92mm, mesh: 8mm - Ø4mm

3D honeycomb square grid model in STL format. Mounting holes are placed at the four corners (center-to-center 92x92 mm), each with a diameter of Ø4 mm. The overall dimensions reach 100x100 mm, with large 8 mm cell size for optimal air circulation. This type of grid serves both protection and ventilation roles.

Parameter	Value	Unit
length or center-to-center	92	mm
width or center-to-center	92	mm
mesh size	8	mm
dual color	no
holes	yes
hole diameter	4	mm

STL: Advantages and Disadvantages for 3D Printing

The STL format is, without question, a cornerstone of 3D printing. This exchange format has established itself as the universal standard for representing 3D models ever since the early days of stereolithography. Its main strength lies in its simplicity: it describes the surface of an object using countless small triangles that form a mesh. This approach, known as tessellation, makes STL 3D files universally compatible with nearly all CAD software and slicers. If you’d like to learn more about this format, check out our article STL: What Is This 3D File Format?.

One of the major advantages of the format lies in this universality: whether you’re using a complex modeling program or a simpler design tool, you can export your 3D models in STL 3D format with near certainty that they’ll be interpreted correctly by your 3D printer. This ease of exchange has played a key role in the widespread adoption of 3D printing, allowing anyone to share and print objects without worrying about software compatibility. Once again, simplicity is its greatest strength.

However, that same simplicity also brings certain limitations. The triangle mesh, while effective for describing geometry, contains no information about colors, textures, or materials. For more advanced projects requiring these details, the STL format starts to show its weaknesses. Additionally, print quality depends directly on the fineness of the tessellation: too few triangles can lead to rough or faceted surfaces, while an overly dense mesh can make the file unnecessarily heavy.

Another notable drawback is the lack of unit management. An STL file doesn’t specify whether dimensions are in millimeters, centimeters, or inches, which can sometimes cause scaling errors when importing into a slicer. Despite these limitations, the STL format remains the go-to standard for converting your 3D models into G-code — the language your printer understands. It continues to be the preferred choice for its robustness and broad compatibility, even as newer formats like 3MF emerge for more specialized needs.

What is parametric modeling?

Parametric modeling is a fundamental approach in computer-aided design (CAD) that reshapes how 3D models are created and managed. Far from being a simple drawing technique, it represents a genuine design philosophy where objects are defined not by fixed shapes, but by variables and intelligent relationships.

This method makes it possible to modify the length, width, or diameter of a part and have the entire design adapt automatically, without the need to redraw everything. At the core of the process are parameters—numerical values (length, angle, thickness, etc.)—linked together through constraints and formulas. For instance, the diameter of a hole can be defined as half the width of a plate; if the width changes, the hole’s diameter instantly adjusts, ensuring the consistency of the design. This interdependence makes 3D models flexible and responsive to changes. One of the main advantages of parametric modeling lies in its ability to simplify customization and enable rapid iteration of designs.

Whether through modeling software such as Fusion 360 or FreeCAD, or through code-based libraries like build123d, this approach allows effortless exploration of a wide range of variations. Such flexibility is especially valuable across multiple fields—from mechanical engineering and architecture to consumer product design. It saves considerable time, reduces errors, and improves the performance of parts.

By defining design intent from the start through these parameters and constraints, the model preserves its integrity and functionality even after numerous modifications. It is a powerful way to transform an idea into a tangible object, ready to adapt to new situations.