The updated and final version! M42 lens to Canon EOS body adapter. Made as a remix from three "things". Many thanks to the authors. Well, it will take a while until I will be able to test it. If there are courageous, please test it...

Adapter assure a flange distance of 45.5mm, needed by M42 lenses to focus to infinity (EOS flange distance is 44mm so, it adds 1.5mm), but, as I have zero experience with 3D printing, there is no dimensions tolerance. However, this is intended to be printed on Prusa i3 using Cura 3D software, where material is PLA and the profile is set to High Quality (0.06mm), infill %100.

Now, what I got from those three things:

• from @SkyRzn I got the entire EOS bayonet, cut the extension tube and kept only 1.5mm from it; https://www.tinkercad.com/things/eZ0xn72o6Zj/
• from @jeng28 I got the secure hole and the index hole of the EOS flange; https://www.tinkercad.com/things/0lSVNIOYrTU/
• from @profhankd I got the first 6 millimeters of the M42 screw https://www.thingiverse.com/thing:132781 .

I should add that the EOS bayonet is procedurally generated in python language, resulting a script for OpenSCAD and it is a (very) tight fit to assure stability (good for metal body flange, but bad for composite body flange as in EOS SL1 body). The program was written by @SkyRzn.

Thank you guys for your work! And special thanks to the guy that tested the previous version and found out that the procedural M42 screw wasn't usable (see the comments). https://www.tinkercad.com/things/jI6Te3Pbb6Y

A big thank you to @Noserider that got this working with a slight change in dimensions. I will make the change in files as soon as he will answer my questions.

BTW, there are some goodies hidden inside the archive...