I machined the head swivel joint mount from Aluminum. This attaches to the forward servo 1/2" servo extension clamp with four 6-32 screws. The swivel joint is a 10-32 rod end and it's attached to the mount with a long 6-32 bolt with machined spacers. The swivel joint allows the head to move up/down and left/right. The 6-32 ball links on the bottom of the mount will attach to the servos that make the assembly move.