Saw some other stuff on here that I thought was kinda lazy. Made the gate from scratch, as "Spintires: Mudrunner" can use the full travel of the joystick. Works like a charm for my purposes and figured I'd share.
This should work as a "slip fit" over the joystick, after you saw/cut/melt the little tabs off. I put about .5mm larger than the diameter of the OD and .5mm smaller than the ID.
i just took some of the self tapping screws from the base of the joystick to attach the gate, then used some good ole industrial Velcro to secure it to my desk.
3d Solutech PLA
Might have to rotate 90 degrees so the big end is facing the build plate
Do what this guy did, but print the handle out.