Quickshape of 8-pointed star aligned over the design.
Line, 15pt, Smooth Curve tracing out one cog.
Rotate and drop off cloned cogs at 45 degrees around centre of gear.
Simple centred circle, 15pt, no Fill.
Grouped and coloured as needed.

8-Cogs.xar

Click image for larger version. 

Name:	8-Cogged Gear Construction.jpg 
Views:	211 
Size:	43.5 KB 
ID:	124813

Acorn