Large Gears template anyone?

I need to make gears that are approx. 4 feet in diameter for a float in a parade.  The gears will line the perimeter of the truck and are going to be made out of 3/4" plywood with metal bracing on the teeth to prevent the plywood from chipping and attached to a plywood background.  It would be awesome if we could alternate 4 foot gears with 3 1/2 or 3 foot gears for visual interest.  It needs to look childlike - so we are not using sawteeth.  I'm going to try to attach a picture with our logo for ideas.  Any help with designing a template or where I could go to get measurements would be appreciated!  Thank you!

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boort6 years ago
I'm sure that you have your parade float built by now but if you need to make gear templates in the future check out This progarm will let you build fantastic, usable, gear trains that can then be cut on a CNC or printed out and cut by hand on a scrollsaw, bandsaw, etc...

Jayefuu7 years ago
I'm pretty sure this is exactly what you're after, though I haven't tested to see if it works to that size:
Nice link.
 Agreed. Wood gears were what came to mind immediately/
orksecurity7 years ago
I'd suggest starting with a picture or sketch of a suitable gear, and using graph paper (traditional), a pantograph (also traditional) or an enlarging copier or a projector (lazy) to enlarge it appropriately.

Graph paper is probably the simplest approach for something this large. Draw a grid on the original picture, a much larger grid on the plywood, and freehand-copy shapes from square to square.