This mounting plate/profile slides over 20mm rectangular pipe and holds standard rack-mount equipment.

The STL model is available in 1U and 2U. Also provided is the OpenSCAD source, which let's you adjust various parameters easily and generate the wings at any positive integer mutiple of 1U.

I print the wing slightly smaller than the standard prescription, to avoid gaps. The ready-made STL models have a “standard” 15.875mm wing size.

These were printed in PLA. You should be fine with other options too.This mounting plate/profile slides over 20mm rectangular pipe and holds standard rack-mount equipment.

Wikipedia has a dimensional model here: https://upload.wikimedia.org/wikipedia/commons/8/84/19_inch_vs_10_inch_rack_dimensions.svg