Grass trimmer connector (7 teeth to 9 teeth)

thingiverse

Prehistory: I snagged two trimmer heads (chainsaw and brush cutter) at a fantastic price. However, the shafts wouldn't fit together with my trimmer. That's when I whipped up this connector. How well does it work: It works remarkably well, considering how often I use it. The connector has broken only once, when the saw got jammed in a cut. In fact, it acted as a fuse that prevented further damage.