J hooks More on reddit.com

You could make your own with some galvanized strapping Or use something like this: https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwij6KORxPP9AhW_CK0GHdSLDHAYABAVGgJwdg&ohost=www.google.com&cid=CAESa-D2frTIJBCpNm2wBrgutxSL729ZbsmsI-iEi3f5zMOtIjGcJtoPuqzTjLmX42XOWgkplyAX69Q0nF4y6K-vk7q32vMpnf9jOINi4-aNaht8w8xuSv9qQZYxkTwCITW2snISEn5jhGgQPPtX&sig=AOD64_2FvZsKgxJCvB6rLIbgqIuNw39wpA&ctype=5&q=&ved=2ahUKEwiMnJ2RxPP9AhVlMDQIHSvTCo8Qwg8oAHoECAYQLw&nis=8&adurl= More on reddit.com

there are hangers that slide into a frame like that ... here is an example: https://www.framedestination.com/prod/s/metal-frame-omni-hangers-set-of-2.html?gad_source=1&gclid=CjwKCAiA-P-rBhBEEiwAQEXhH-YLUamB6buYAI1FLrf-DpR0jatzTz-aAkkITSs_UpLhFg9u-9x-kBoC49kQAvD_BwE edit: the idea with those hooks is that you connect across the frame to hangers on each side with wire and then put that wire over a picture hook. unfortunately, there are many styles and track sizes of metal frames, so not a universal fit. A Michael's, or other craft/framing shop might be able to hook you up. Or, in a pinch, the tab of a conventional picture hook and hook in that slot, but the top of said hook is likely to project above the top ... but, so careful bending of the hook may allow you to minimize that. Depending upon situation, the head of a nail can also fit there and hold the frame secutely. All that said, any number of other make-do approaches can be taken that MIGHT work out okay. More on reddit.com

It's an aluminum frame, so it'll be easier to drill through than stainless steel. You can you self tapping screws or drill and tap for machine screws. Your biggest aim is to use something where the threads are closer together because that metal is only about ⅛ inch thick. More on reddit.com