Requires 4 - 6mmx6mmx4mm momentary tact switches.
A screw tap set comes in handy as well. Tap the center of the button pusher and and tap the end of the joystick arm. Also tap screw holes and set 4 small screws to hold the top down.
Second joystick arm is to allow them to cool properly while printing. Omit if you have proper layer cooling.