Any ideas on how to scratchbuild timing gear?

Well, just as the subject says,any ideas? I`m trying to replicate the wheel/gears on a DOHC. It´s beltdriven , not by chain. So the ones i´m talking about are the two on the camshafts.
I´ve been thinking about scratching it out of styrene, but what´s the best way to replicate the grooves? Aftermarket is not an option ;)
Maybe using the Dremel as a lathe and make them of aluminium?

Ideas?

http://img31.echo.cx/img31/1867/26139np.jpg

You mean the grooves such as the non purple part?

You can take a flat rubber band to fit on the cam gear and take some aluminium foil and make the grooves and super glue them to the rubber band. Then place the the rubber band around the cam gear.

Easy. Get some styrene tubing and som strip styrene, and glue on pieces of strip onto the tube exterior.

Something that small a scale would be easier to do some sort of subtractive construction. Or something. I would take styrene rod of the right diameter (sprue could work in a pinch, but note that sprue is often not round but two offset semi-circles because molding processes are crap), put it in my mitre box, get out my finer toothed razor saw, and draw the rod under the saw so that the teeth make grooves in the rod. Then, cut the grooved rod into circle bits and dril the center out for releif, drill out a small hole in the center and in the block you're mounting it too, use very thin styrene rod to mount it, passing it 1mm through the center hole to replicate the end of the cam, and then wrap it up with the crank pully with a couple go-'rounds of masking tape, paint it dirty black, and there you go.

Is there anything you don't have the answer to Will? LOL =) I wish I could have all the knowledge like alot of you guys do to make a 100% custom flawless detailed model. I'm trying with the corolla...

easiest way is to by some mini cog wheels you often dind them in small electrial stuff, floppy drives use them to move the "reader" you can prob find them at somewhere like radioshack maybe (i dunno, i live in england) just trim to siza and glue !