Jabba's Door Droid - the gearing

Next bit to address on the Door Droid is the strange, almost medievial side parts. They're quite hard to make out but seem to be some sort of chain/gearing affair, with spikes all over:



For the main bits i'm using cotton reels.
I measured the distance between where they'd be going and drilled two holes that distance apart in some Plasticard and bolted two reels down.
I then eyeballed where the lower one in the middle would be and again bolted another reel there.
And you can i've rivetted a strip of Plasticard between the two upper one's, looped around the bottom one.
I think the original is a definete chain affair, but i'm not too bothered about using a solid strip of plastic as, with all the detail on, i don't think you'll see too much of it anyway.