The neck bin is made from 1/4" dowel triads pushed through holes in 3/4" MDF rings, cut with a router on an extension arm. MDF is very dusty, so wear a mask and do this outside unless you have a good dust capture system.

I had to go to a specialty tool shop to get a 3/4" deep chamfer bit for the router.

There's an inner bin as well which is wrapped with weed matting and the black bug screen used for screen doors.