This model is meant as a placeholder in your design of a custom joystick case and possibly a custom knob. The dimensions, places of screw holes and the restriction of the knob movement is taken from the popular PS2 analog joystick module for Arduino as for example sold at https://www.banggood.com/PS2-Game-Joystick-Module-For-Arduino-p-76465.html?p=TH241428726122015109 (affiliate link). I used this module to build a custom case which finally resulted in a "joystick mouse" for handicapped.