Round Belt Generator

thingiverse

This script generates a round belt designed to connect two pulleys. I required a replacement belt for my son's rock tumbler so printed one with semi-flex filament. One week later and it remains strong, prompting me to publish the OpenSCAD script with customizer inputs as a precaution. The code to generate a torus is straightforward using rotate_extrude(). Simply create a circle, offset it along the x-axis, and apply rotation. For a torus with major and minor radius of 48 and 1.5, the code would be: rotate_extrude() translate([48,0,0]) circle(r=1.5); Determining the length of the belt based on pulley sizes and distance between them posed more of a challenge. If you have the original belt, simply measure it and compute the radius with L / 2pi. If you don't have the original or if it's for a new design, there is some math involved. To make things easier, I added this function to the script: function belt_length(R, r, d) = 2*d + PI*(R+r) + (R-r)*(R-r)/d; To facilitate printing, I included an option for an octagonal cross section. Since using circle() to generate regular polygons yields one that's circumscribed from the given radius, you might have to increase the belt thickness slightly.