Thursday, March 23, 2017

How to make a rubber band powered formula car toy

I made this piece out of scrap pieces of wood, I had laying around in my shop.

The car takes energy from a rubber band mechanism in order to move. 

The main body of the car is made of a scrap pine piece. I cut it to size with a handsaw. 

I trimmed it’s edges on the bandsaw and used my disc sander to remove the previous finish.

All the parts of the car are symmetrical. I designed my half templates out of a piece of cardboard. I used a sharp exacto knife to cut the templates out.

I then traced around the template, flipped it over a traced it’s mirror image.

I cut all the pieces out on the bandsaw. 

I made the front wing of my formula out of an MDF piece. I traced it on the body in order to create a notch. I cut the notch using the bandsaw and a hand saw.

The holders of the back wind are identical. So I rough cut them on the bandsaw and glued them together with carpet tape. I then sanded them flush on the disc sander. I sanded the inner curve with my rotary tool.

I then sanded everything with my disc sander, rasps and sandpaper. 

I marked the positions of the wheel holes and used a drill to open them.

I wanted to create a chamfer on the top of car’s body. I could do this round over with my router, but to make it more DIY I used my cylindrical No2 rasp. I traced the the thickness of my chamfer with a pencil and then finished the job with a rasp and sandpaper. 

I glued and screwed the front wing in place. Before adding the screw I predrilled a pilot hole and counter sinked it. MDF can split really easily so the pilot holes are necessary in most cases. 

I mounted the driver on the car using glue and a dowel. I used a dowel position marker to mark the hole before drilling.

To reinforce the back wing holders I inserted two small nails before glueing. 

I then glued the back wing in place.

I used a hole saw to cut the wheels of the car and the flanges for the wheels.

To sand the wheels, I attached them on a threaded rod with two nuts on the top and two on the bottom. I then mounted them on the drill press and using it as a lathe I sanded them. 

I used a similar technique to turn the rubber band wheel. Only this time I used my rasp to shape it.

To reinforce the back wing. I glued in place bamboo sticks which acted as mini dowels.

I then added the first coat of spray paint to everything. I applied two coats with light sanding between coats. To create a double color effect, I masked the areas with blue tape and sprayed the rest with a contrasting color.

I finished everything with a couple of coats of glossy clear varnish.

I glued the wheels and the flanges in pace and used a flush trim saw to cut the dowel flush with the wheels. I used a scrap card board piece as a mask to paint the exposed edges of the dowels.

The rubber band is mounted on metal ring which is screwed in place. The other edge of the rubber band goes to the pin on the back wheel. When you turn the back wheels backwards the rubber band gets wrapped around the back wheel holding energy. When you release the wheels convert the energy of the rubber band to a rotating motion.

To increase the car’s traction, I cut a few pieces of rubber from a bicycle tire and wrapped them around the wheels. 

My little toy was now ready to roll!

You can download a free template of my car here (if the link expires, ask me to send you the template via a Facebook message):

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