I made one out of heavy chain link. I attached a 10’ piece to a 10’ pipe. The pipe has an approximately 13’ chain welded to the pipe, end to end, and the chain is what’s used to pull it. The pipe keeps it from bunching/folding, and I’ve wired some old tires on top of the fence for weight. Works decent, but doesn’t do a great job on hard piles. The chain link really does a good job of breaking most piles into very small pieces, but needs something to help with the older piles. I have an old spike harrow I always think about stealing the spikes from and welding them onto the drag, just never get around to it.