scad-klupe: Threaded fasteners for scad-clj

This is a Clojure library for use in CAD work with Matthew Farrell’s scad-clj. It provides models of threaded fasteners, including nuts and bolts.

The Lojban word klupe refers to a screw or bolt.

Models produced by this library are neither perfectly accurate with respect to standards, nor engineered for ease of printing. Their main purpose is to form negative space: Relatively simple shapes used to carve out screw holes, nut pockets and similar cavities in 3D-printable designs. These holes would then be filled by ordinary steel nuts and bolts in the assembly of your product.

scad-klupe is compatible with scad-tarmi compensators to deal with printer inaccuracy.

Usage

The main interface is the iso module. If in your ns declaration you (:require [scad-klupe.iso :refer [nut]]), you can then call (nut {:m-diameter 6}) for an internally threaded approximation of an ISO 262 M6 hex nut. Its height and external diameter are inferred from the standard, unless you pass overrides. For a matching 25 mm threaded bolt, call (bolt {:m-diameter 6, :head-type :hex, :total-length 25}).

If you intend to model an M6 nut to carve out negative space for a real nut, the correct call would be (nut {:m-diameter 6, :negative true}), a less complicated shape without a hole. The bolt function also takes a negative parameter, which elides the drive from the head, but the negative of a bolt is still threaded by default. If you just want a straight hole that you intend to tap instead of printing the threading, try passing :include-threading false to the bolt function.

Showcase

You will need to use scad-clj, for instance via scad-app, to produce OpenSCAD code for the objects you model with scad-klupe. Check the showcase code for examples of how to do that. A selection of the models produced by that code are shown here.

Contributing

Volunteers are welcome to submit patch sets for review, including additional ISO and DIN standard data, more types of heads and drives, and non-metric standards.

Acknowledgements

scad-klupe was broken out of scad-tarmi in 2020 while making backwards-incompatible changes to the API for programmatic use and taking a more consistent stance on parameter schemae and bundled defaults.

The thread-drawing function (scad-klupe.base/threading) is a reimplementation in Clojure of a corresponding function in polyScrewThread_r1.scad, created by aubenc at Thingiverse.

License

The thread-drawing function (scad-klupe.base/threading) reimplements work in the public domain, as acknowledged above. This specific reimplementation of that function, and the rest of this library, are licensed as follows.

Copyright © 2020–2021 Viktor Eikman

This software is distributed under the Eclipse Public License, (EPL) v2.0 or any later version thereof. This software may also be made available under the GNU General Public License (GPL), v3.0 or any later version thereof, as a secondary license hereby granted under the terms of the EPL.