For project I am currently working on, i needed something to help me sand it, and I got tired of my hands cramping when holding the small wooden pieces, so i designed this small clamp. Clamping part itself its 2 mm high, 40 mm wide and max length of objects it can clamp is 45mm. To work you need:

1x  M6x70 (anything over M6x50 works its just smaller travel)

1x M6 nut
optional: usage of 1x washer

I have printed it with PETG; and after a month of use its going strong, some minor defects on points of clamps, due to testing of clamping force :)