I design this magic bolt and nuts using Fusion 360 in an extremely simple way. If you use the same idea and concept you can design your model as well. They are very smooth and works very well.
One bolt is 60 mm long and 20 mm in diameter. The long bolt has 120 mm which is good for play. Two nuts L and R represent rotation in the left and right direction. LR means any direction can go. You can also scale them in the printing process.