Installing the Lights on your Pinewood Derby Car

While waiting the arrival of your PinewoodLight Kit you can begin building your car. Installation and car construction will follow these basic steps:

  1. Make a cavity in the car to hold the circuit board.
  2. Carve and shape the Pinewood Derby car.
  3. Drill holes for the lights and wires.
  4. Finish final sanding and painting.
  5. Install the lights and connect them.
  6. Mount the circuit board and attach the sticker.

Download detailed instructions and watch the videos on this site.

Pinewood Derby Car Block Showing Cavity.

Have an idea in mind and a drawing of how you want your Pinewood car to look. You need to make sure that the design is compatible with installing the lights. Plan the location of both the lights and the circuit board. Since Pinewood Derby rules require that the car be only 7” long, if the lights extend beyond the front or back you will need to trim about 1/8” off of one end of the block. The light kit and the basic car kit together weigh less than the 5 ounces allowed so weight should not be an issue.

The Pinewood Derby track has a raised portion in the center (between the wheels) so if you mount the circuit board as recommended underneath the car, it MUST be recessed into a cavity (hole). Do not place the circuit board at either end of the car since the wires are not long enough to reach.

There is enough track clearance for the wires to run along the bottom of the car provided you used scotch tape to stick them down flat.

One installation method is described here but this will be unique to every Pinewood car. The circuit board can be hidden in a cavity underneath, covered with paper or plastic or left exposed depending on your design. Similarly, the wires may be hidden internally or run along the bottom or sides of the car.

Use your imagination!

First, Carve a Cavity in the Pinewood Derby Car Block

It’s easiest to carve the cavity before shaping the Pinewood Derby car. Choose a location near the center of the car on the bottom to mount the circuit board. Carve out a cavity 1 1/8” wide by 2” long by ¼” deep. This is slightly larger than the board to allow some room to work and slightly deeper to allow room underneath for the extra wire.

pinewood derby block showning preferred location for installing circuit board

Trace around the circuit board on the bottom of the car block to mark the size of the hole and cut outside the line. Remove the wood to a depth (adult supervision) of ¼” with a chisel or a drill.

Use a chisel to carve the cavity

With a chisel, pound it straight down about 1/16” outlining the marked hole. Be careful near the edges so that you don’t split the wood. Then using the chisel at an angle, remove the wood in the center working with the grain of the wood. Repeat this process 3 additional times until the opening is uniformly ¼” deep (about the depth of 3 stacked nickels).

Alternatively, use a drill with a forstner bit, spade bit, or even a normal ¼” drill bit. Wrap some tape around the drill bit ¼” above the end so as not to go in too deep.  If using a spade bit make sure the tip doesn’t go through to the top of the car.  Drill out all of the wood in the cavity to a depth of ¼”. Use a small chisel or a utility knife (adult supervision) to clean up the cavity.

 

Second, Drill holes for the Lights

After you have finished shaping your car you need to drill holes to mount the lights and route the wires to the bottom. Use a drill with a 5/32" bit and drill holes about 1” deep for the front and rear lights.  A 1/8" bit can be used for the headlights but you'll have to enlarge the entrance slightly to fit the base of the lights. If you want the wires to go under the axle grooves you'll have to drill about 2" deep on one end of the car.

Drill Instersecting Holes into the bottom of the Pinewood CarDrill holes for the front lights in the Pinewood Derby Car

 Note: The Pinewood car shown here has side pieces added to make wheel fenders. It's still a legal width. The top has been hollowed out to remove wood so that it will only weigh 5 oz.

Then, drill bigger (1/4" or larger) intersecting holes from the bottom of the car to provide a route for the wires from the lights to the circuit board cavity. Avoid drilling through the axle grooves so you don’t interfere with the wheel installation and don't drill through to the top of the car.

Finish the final sanding and paint the car before installing the lights (next step). You should wait to install the wheels until after the light kit is completely in place.

Third, Install the Lights on your Pinewood Derby Car

Install the lights after your Pinewood Derby car has been painted. Wait to put the wheels on so you don't mess up their alignment while working on the lights. Route the wires from the clear headlights into the front of the car and out of the intersecting holes in the bottom.

Push the lights in place into the Pinewood Derby Car

Pre-bend the ends of the wires slightly so that they will follow upward into the intersecting holes. It's best to PUSH the lights and wires in place. If you must, pull very gently on the wires or they may separate from the lights.

It can be a little tricky to grab the wires in the intersecting holes in the bottom of the car. Tweezers or small needle nosed pliers can help immensely. Work carefully and get the lights aligned how you want them. The lights may fit snugly enough that no glue is needed although you may want to use a small amount of hot melt glue or wood glue. Don't use solvent based glues as they may dull the lights.

Pinewood Maserati Front view Pinewood maserati showing rear lights.

Front and back views of a Pinewood Maserati with Pinewood Lights installed.

Fourth, Twist the Light Wires Together

Gather  the bare ends of each color together.Turn the Pinewood Derby car upside down and with the circuit board laying loosely in the cavity with the battery side facing DOWN. Sort the red and blue wire ends so that they are near each other.

Collect and align the bare blue wire ends between your fingers as shown in the picture and twist them tightly around each other all the way to the end of the bare portion. Then bend the wires into a hooked shape.

Similarly, collect the bare ends of all four red wires together in the same way and twist them together, forming a second hook.

Image of twisted wires. Form a hook.

Bottom View of Pinewood Derby car showing wires.

 

When you are finished it will look like the picture to the left. You are almost done and will connect the wires to the circuit board in the next step.