I got inspired by a public domain design of a clothes peg that is printed in one piece and decided to create it in Solvespace. The spring on the peg works surprisingly good even with regular PLA.

EDIT: I've added a modified clothes peg (clothes_peg_v2) as opposed to the original (clothes_peg_v1). Both are still available for download. Clothes_peg_v2 can be opened wider while the beak is narrower. See image where the green peg is the original and the red peg is the new one. I've also added a radius to the beak so it's easier to move over the clothes. I find 50% infill of the print giving good results.

Both Solvespace files are available to change the source files (.slvs). Solvespace is a free and open source, easy to use 3D CAD program that works on Linux, OSX and Windows.

Solvespace can be downloaded here: [https://solvespace.com/download.pl](https://solvespace.com/download.pl) or from the repository from your favorite Linux distro.