YOU WILL NEED:
Spare NES Dpad
Epoxy for Plastics
Step 1: Getting Directions
I started by finding an extra joystick (from a 360 controller) and dpad (from a NES controller). Then I took the joystick and clipped the dome off of the bottom portion until only the core was left with 4 protruding plastic bits (keep those bits on there). Using a phillips screwdriver I opened the controller and removed the Dpad. I drilled the center of the dpad out the size of the joystick core and cut an x out between the directions for the plastic bits on the joystick to fit in.
Step 2: Bond Them Together
I used a loctite 2 part epoxy for bonding plastics together. Just put the loctite in the hole you drilled in the dpad and put in your joystick (after you make sure the joystick fits good in the dpad) and let set for 24 hours for max bond.
Step 3: Reassemble and Play
You may have to cut the corners of the dpad slot to fit the joystick back through but it still looks fine when done neatly. I also added a joystick cap to match the Nintendo NES theme.