So you have a Gravis GamePad! Very cool. But you're missing the joystick like everyone else. Maybe you've got an old 8/32" bolt screwed in that you use instead, which is nearly as uncomfortable as the original stick.
The original joystick has plastic threads which screw into the gamepad, but these would be quite fragile if 3D printed. Instead, there's a 0.6" deep hole in the model where you glue in a 0.75" length of threaded 8-32 rod. Or just get an 8-32 screw and cut the head off. It should protrude 0.15" below the bottom of the joystick handle.
Enjoy!