30mm dumbbell/barbell thread

thingiverse

I'm using 20-pound barbells at home and wanted to create a helper-tool for bench pressing. After five days of studying engineering tables, I still hadn't found the corresponding measurements and so took a digital caliper and a balance scale and created the threads myself. The published STL files contain one complete turn of the inner and outer thread of those 20-pound barbells. Just stack them on top of each other as many times as you need, cut them off at the desired height and print your threads. Inner threads have a 1/4 inch tolerance compared to outer threads. STL files are scaled up by a factor of ten thousand.