The camera stabilizer has a 3 foot vertical shaft made of 5/16th inch (18 threads per inch). The shaft was cut into 3 1 foot pieces.
The bottom and middle pieces are connected using a standard female/female 5/16th inch connector.
The middle and top pieces are connected with a custom built connector. It was built out of 1 inch aluminum rod that was cut to 1 1/4 inch long. I drilled a 1/4 inch hole down the center of the shaft. For the direction control handle I drilled a 13/64th inch hole half way into the shaft.
I then tapped each end of the shaft with a 5/16th inch (18 tpi) tap. These two threaded holes are used as the connection between the top and middle section of vertical shaft.
The 13/64 inch hole was tapped with a 1/4 inch (20 tpi) tap. After tapping this hole a 1 inch set screw was inserted into the hole. The direction control handle was then screwed onto set screw.