Tumbling Knife Sharpener

This is a print of a tumbling knife sharpener, as popularized on social media. The magnetic knife holder offers angles of 15° and 20°. The sharpener itself has two sides onto which magnetic sandpaper plates can be attached. You can glue any kind of sandpaper onto them, in my testing 320 and 1000 grid worked really well. Since these plates are meant to attach via magnets, you can quickly replace them, and you can also use fairly strong glue, so that even if you can't remove used sandpaper, not much is wasted.
However, in my testing spray glue worked well and made it so the sandpaper could be removed fairly easily once used up.

Note: You may want to adapt the magnet holes to fit your size of magnets. Or simply use a Dremel after to widen them a bit.