Instructables

(Very) Cheap and easy cart for a Science Fair Project...

Picture of (Very) Cheap and easy cart for a Science Fair Project...
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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!
 
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Step 1: Check Out the File - built for 1/4" MDF...

Here're the vectors and (not necessarily needed) text for the wheels, brackets, etc.  

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.

Step 2: Put it all together

Picture of Put it all together

I used CA (super) glue to put it together and save time.

The axles are about 5.5" long.

Step 3: Burn the 1/4" MDF


Attached is the file for cutting the pieces, in both .cdr and .eps.

I used the laser engraver to cut the pieces for the cart.   The 60-watt laser ran at 10% speed and 90% power for this successful cut.


Step 4: And Assemble...

Picture of And Assemble...

I finished with 10 (separate!) fingers - another successful use of CA glue!

The test cart for the Soda Bottle Rocket is all set!  We'll use rubber bands to hold the soda bottle on the cart...
togo1919 (author) 1 year ago
The 1 cup of vinegar and 2 tbsp of baking soda propelled the cart 131"!!!
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