I designed these C-shaped spacers for the Lazy Susan in my kitchen cabinet, so that maintaining shelf height won't depend on the friction of a measly set screw against the 20mm spindle. Each spacer is 20mm tall. I clipped 13 of them to the spindle, in a stack. Now I won’t have to keep fighting this thing twice a year when the top shelf falls onto the contents of the bottom shelf, trapping them.