Printed plastic will not be much better than wood... actually I think properly treated hardwood will be way better.
I saw some examples of using
brake disks for that - it doesn't cost much and machining is minimal.
I also use 3D printer for a lots of stuff... but not where structural strength and stability is required (after all, what is the point in building a permanent pier when you have to adjust before every use?).
BTW,
this is how I did it.