I didn't liked the Gearwheell, so I went back to Inkscape, made a new 9 teeth gearwheel, and did Path>Dinamic Offset to it.

Changed the Offset, from Object to Path, combined the 2 Paths, and done the labourious routine of eliminating the curved segments, and joining the straight lines between the 2 Paths, that's Break Path at selected nodes, and join selected nodes with a new segment...

Ended up quite well, if I do say so myself;

I've added 9 edge pieces, with pegs, for the contour of the teeth, and a piece with the lenght of the teeth base's circumference (plus a bit, to overlap and glue), to strenghten the thing, voilá:

Here's the Sgv file, for you to try your hand at this:

9 Teeth Gearwheel

I'll try and make a new gearwheel outta this, a proper one, with decent folding, and made of Cardboard, Mañana...