What hardware to use when building MDF furniture that will allow me to take it apart?
I’ve built a lot of Sauder furniture in the past, and they come with these special plastic or metal inserts that can be attached and removed without damaging MDF. I think those are the collars you’re talking about. But I don’t think I’ve ever seen them in hardware stores. They’re real specialty stuff so they’re hard to find. But you could use some kind of clamp. You would permanently screw or glue the clamps into the board, but could then release the clamps when you need to take the furniture apart. Unfortunately, Home Depot isn’t loading for me right now so I can’t link you to anything there, but if you go in store you should be able to find something that works for you. Good luck!!