Chain links and small length of chain of the type typically found on bicycles. Drawn up from the ANSI 40 chain size, dictating the roller and pin diameters and pitch.
I used 120pixels/inch, so the center to center distance between pins on a link (the pitch) is 60px.
There are some hidden paths to mark the center of the pin, so if you use the snap to path option with snap to line segments and snap to rotation centers in Inkscape it should allow you to set the rotation point pretty precisely.