Yesterday a group of Girl Scouts and their leaders came over to the garden to learn about growing vegetables in a dry climate. One of the things we talked about was the importance of amending the soil with lots of compost.
They are both made of cedar 4×4 posts for the corners, and sides of hardware wire and cedar boards. The front of the bins have these removable cedar 1×6″ boards, which have holes that simply slip over the heads of bolts in the posts:
Organic matter goes on the top, and eventually, compost comes out the bottom. I remove the boards to get at the composted material, and the whole cycle keeps on churning. It’s been a good, durable system for several years now.