Compression Spring (small)

A 16mm compression spring, 32.4mm free length — 6 turns of 2.4×2.4mm section at 5mm pitch, with a flat ring closed onto each end. The section is rectangular on purpose. A round wire curves away under itself on the inside and outside faces, which is the same overhang a horizontal cylinder has; a rectangle's faces are dead vertical, so the only unsupported thing left is the leading tip of each layer's arc, and with the pitch near twice the wire height that arc is most of a turn and its tip advances a few degrees per layer. It also puts more material where a spring is actually worked, which is in bending. The end rings are what let it stand up: without them the helix starts at a single tangent point and the first layer is a sliver with nothing to grip the bed. They are what "closed and ground" ends do on a real spring, and they give a flat face to push against. TPU if it has to survive being compressed more than a handful of times — PLA will make the motion but it creeps under a held load and eventually snaps. This is a light-duty printed spring for a detent or a return, not a substitute for a wound steel one.

from £1.01example, in PLA