Door Stop Spring

This is a good solution to a dumb problem.

My office had a really heavy hydraulic on it that allowed the door to automatically close. But, I wanted it to stay open when I was in the office. I had a simple block of wood, but that meant fumbling around with the block every time I came in / went out, so I got a door stop like this one:

https://www.mcmaster.com/door-stops/lever-door-mount-holders/

Which worked great to keep the door open. However, to get the door to close, I had only bad options. I could lean over (ugh), I could try to get my size 13 shoes under the lever to prop it up (waste of time!). My first solution was to tie some string from the door handle to the lever, so I could just yank the string to get it to close.

Then I remembered, I own a 3D printer.

This little device is meant to house a small spring inside the cylinder. The post is 7.5 mm, so a spring that is normally about 7 mm diameter should stay on the cylinder once put into position. The device