I had Issue with JP's model. I couldn't get the cap to fit I also didn't have cap head 4mm screws. They were more button head. So I modified it a little.
You will need supports.
Thank's to JPMakeStuff for the original!
The author remixed this model.
I added a taper to the cover plate and the part it goes into
I also widened the recessed part for the 4mm screws so non cap head screw would fit. I also opened up the hole a little for the screw so it would pass through easier.
Thank's to JPMakeStuff for the original!