Corner fastener

thingiverse

I personally prefer using standard RV corner fasteners that are commonly found in older RVs. They work flawlessly and outperform their original counterparts. While they may not be the most visually appealing and lack a cover lid, making them somewhat unsightly, you can easily conceal them from view. If someone were to request it, I could definitely create more aesthetically pleasing versions with a cover lid, but for my own purposes, that level of customization wasn't necessary.