Belt design inspired from the conveyor belts in Factorio.

I made 6 sizes between 70cm and 1m. There is a file with 3 belt sections that you can use to extend it with a bit of snip work. Each section adds 20mm. (also could save you a lot of time if something goes wrong in the print. See the picture of the back end of a test piece to see how to cut it without loosing too much strength. If done right, it's hard to get in and it won't fall out.

The belt itself is fully printed in place. The gear buckle and the coloured inserts are printed separately.

700mm = 34 inserts, 740 = 36, 820 = 39, 880 = 42, 940 = 45, 1000 = 48.

The ends of the belt have a fair bit of overhang, but I managed without supports, though it did require a bit of cleanup. I used 1.6mm walls to make sure it's got enough strength to hold up, but you might be able to get away with less.

I would recommend printing the test piece and the buckle first and making sure it works before diving into the long print time of the full belt.