My second-grade son is entering his Science Fair, and needs a cart for the soda bottle rocket he's making.
I pulled my Corel Draw skills together to come up with a (simple?) wheel and cart-body design to build and use for the project.
Here are the drawings and project pieces I designed at TechShop in San Jose.
Including the free metal rod, the total cost was about fifteen cents!
Step 1: Check Out the File - built for 1/4" MDF...
I promise the wheels aren't perfect! I recognized afterwards that I'd set some of the vent holes off-center - but this is not so critical for the project.
It happened that the scrap rod I found for the axles was .188" diameter. I compensated for the laser kerf a bit and made the holes in the wheels and 'washers' about .188 diameter. The "axle nuts" are around .186" diameter for the inside.
The drawing has lots of extra stuff - remove as needed.