Simple and fast to make filament construction if you want your filament loaded from the top of the printer. Useable on every Open Beam delta printer.

Print with support on, my settings were shell thickness .5mm and the same for the top and bottom .5mm and a infill of 25%. 
Best to print in the position shown in the last picture because there are 5 small points for the ball inside the joint cavity. 
You will need a rod of round 6mm and length depending on your size printer to make the connection between the two parts.