https://www.amazon.com/gp/product/B07R7PR72H/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
This is the tube of bearings I bought for mine, then I built it up based on the size of those bearings. A trip to a hardware store with a bearing in your pocket is probably going to suit you better. I used some old feeler gauge to fashion a washer a bit thicker than the width of the fret tang to separate the two bearings that the tang rides in.
https://old.reddit.com/r/Luthier/comments/jxrh2m/my_take_on_the_diy_fret_wire_bending_machine/
I made a fret end file using a cheap needle file from a Harbor Freight set and ground a safe edge into it. Eventually I went on and bought a real crowning file but the needle file got me by for a long time.