Parametric Funnel with Optional Hook, Loop, or Vent

Introduction

This is a fully parametric funnel — every important dimension can be adjusted to fit your needs. The model is provided with its OpenSCAD source, so you can easily generate the exact size or configuration you want.

Key features:

🧩 Configurable geometry — set funnel diameter, height, wall thickness, and spout size.

🪝 Optional hanger — choose between none, hook, or loop (mode = 0/1/2). The hook version works like a traditional retaining hook to keep the funnel from slipping into the bottle. The loop version can be sized to drop over a bottle cap, letting you keep a dedicated funnel with each bottle.

🌬 Optional side vent — add a vertical air vent channel to prevent airlock when pouring into narrow-neck containers.

⚙ Parametric OpenSCAD design — adjust everything from the top ring thickness to the loop diameter with simple parameters.

Ideal for laboratories, workshops, or household use — anywhere you want a neat, customisable, and reusable funnel solution.

Parametrisation

Different sizes are set in code. Every variable at the beginning of the scad source file can be adjusted. The code tries to cope, but there is no proper error checking. That you need to do visually, possibly when you go to slice the model.

The main five variables determine the diameters and height of the funnel. Their meaning is indicated in the diagram on the right.

The handle (hanger) of the funnel is fully parametric. You can choose between three modes: 0 = none, 1 = hook, or 2 = loop. Once a mode is selected, the handle dimensions — including ring diameter, hook height, hook width, and hook distance from the rim — can all be adjusted individually. This allows you to create a hook or loop that fits your bottles, containers, or storage preferences perfectly, while keeping the design clean and easy to print.

Finally the vent, for which you can set the diameter. If you set it to zero, the vent won't be there.

Pre-calculated models

As examples of sizes I used previously, or considered useful out of the bat, I prepared the following stl models for direct download. The dimensions are in mm, internal diameter (ID) given where applicable

Most models share 1.2 mm of wall thickness, except for the smallest ones. It can be modified, but I found it adequate for all applications. 

💬 Other custom size?
If you don’t use OpenSCAD or prefer not to generate your own models, feel free to suggest a custom funnel size in the comments!

Printing

The funnel is preferably printed in PETG, but you can use PLA or whatever else material in a pinch. A standard 0.4-mm nozzle is fine, and 0.2 layers too, unless you need to print really steep overhangs.

Note that the funnel prints best top-down, so rotate the resulting STL in the slicer by 180 degrees.

It is possible to print the funnel also in vase mode, but only with a loop hanger, or with no hanger at all.

⚠ Warning: Be sure to use food-safe filament if you plan to use your funnel for foodstuffs!