When the plastic buckle for adjusting the straps on my son´s backpack broke I found a ruler quickly measured the buckle and drew it in tinkercad. It´s more a practical and quick design than a thing of beauty, but it took 10 minutes and 30 minutes of printing. I replaced both buckles and the backpack is now ready for school again

The strap is 1” wide (25 mm)

Machine and filament used are from www.3dprinter.no

This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/6ew154ZNS43