Threaded Tubes II

I have made improvements to my previous tubes thing. Now the threads are smooth and stronger. I have included tubes, tube connectors and diameter adapters for metric sizes 18, 24, 30, 36, 42, and 48.

I have included the OpenSCAD script if you want to generate other sizes or something completely different.

Filename decoder:
adaptor_x_y_z.stl: adapt from x to y, and is z mm tall
connector_x_z.stl: connect tubes of size x (male thread ends), and is z mm tall
tube_x_z.stl: tube of size x