Gravity box hay rack

I need to make a couple of more thrower racks for before the spring. is it possible to use the frame on a wagon like the one pictured to build a decent size hay rack and do the frames extend? I would imagine they're heavy enough. I'm trying to find hay rakes and all the ones that are reasonable for my small operation are junk... I figured I could buy one of these scrap the box to recoup some money and build a decent hay rake or two. thank you for any ideas and or suggestions. have a Happy New Year to you and yours!

Gravity box hay rack