Intro: How to Create a Pinewood Derby Car
Well, here it is Pinewood Derby time, again, for our Pack. We hold the Derby in January and hand out the car kits at November’s Pack Meeting. Each year the Cubs need to create a new car. They can’t use last year’s previously experienced car. We run two sets of races. Cubs race against Cubs, and Open Class, is for everyone else. Now I will show you how I set about creating a Pinewood Derby Car for the Open Class, although everything I show will be allowed for the Cubs cars. Remember that there is no “Pinewood Derby Car Police” which will rule on how the car is created. The cars are only judged on whether or not they meet the stated, race time, requirements, as found on the paper included with the kit. Here we go!
Sand paper (Grade, 120, 140, 180, 220)
Knife or hack saw or rotary tool
Paper cups (to set the car on while being painted)
Square (to see if the axel channels are square to the car, if not, you will need to redo them)
If your Pack provides you with a kit, use that. Otherwise choose a kit. You can use an official BSA kit or ones available at local craft or hobby stores. I chose the one in the middle, except I hate the solid piece axels, so I traded for the nail axels in the kit on the left. Also the completed car, with added weights, needs to weight no more than 5oz (or 142 grams).
First thing you need to do is see if the axel channels on the bottom of the care are square to the car. If they are not, fill in the channels with wood filler. Once dry, sand it down and re drill the holes using this, a body tool. Follow the directions with the tool. Mine were straight so I didn’t have to use it this time
This kit has a wedge shaped piece of wood. I like wedge shaped cars. One less step makes me happy. I decided to actually follow the instructions in the kit (up to a point) this time. So I cut out the templates for where to cut the cut and where to place the plastic pieces. I laid them on the wood and used the pencil to draw where I wanted to cut wood away.
A certain tool was out in the shed in the back yard, and it was snowing, so I choose not it use the hacksaw to cut away pieces of the car. (If I were helping a boy make the car, I would have made the trip.) I pulled out a box cutter that I am familiar with and started to whittle the places I wanted gone a little at a time. (If your Cub hasn’t earned his Whittling Chip Card, don’t let him anywhere near a car with a knife, with or without adult supervision.)
Once I decided, I had carved enough off, I took a piece of sand paper wrapped it around a block and started sanding, until every part of the wood was wonderfully smooth.
I cut the plastic pieces available in the kit out and sanded the cut edges smooth on another piece of sand paper.
At this point, I got out my digital scale and weighed the car body, with wheels, axils, and plastic parts, to see how much weight I would need to add. The kit I choose included weights, so I determined that 2 strips of weight with their screws would bring me within 6 grams of 142 grams.
I decide to have the weights recessed into the bottom of the car. I used the pencil to trace where I wanted the weights to be and I, again, hand carved the hole (half the depth of the weights) with my box knife. I tried the rotary tool, but that did not make me happy. I sanded the bottom of the hole, smooth, before I screwed the weights into place.
I consulted the instruction sheet, again, and after deciding to make a couple of changes, I glued the plastic pieces to the body of the car. I let the glue dry for 12 hours.
I had decided to paint my car hot orange. It turned out to be a big mistake. Okay, it was ugly. I repainted the car with some black spray paint I had left over from another project. I sprayed a coat, and let it dry. I did a second coat and let it dry. I then, I turned it over and repeated the process on the bottom of the car. I let it dry overnight.
Once dry, I applied the dry transfers included in the kit, to the painted car body. Hurray the car body is done! Not too bad, not perfect, but then I never was one who could do perfect.
The wheels can be worked on while the glue and/or paint dry.
The wheels and axels can make or break a car. You will need to remove any seams on the wheels themselves and make sure that the axels are straight and shiny smooth. The nails that are used for axels have little seam burrs near the place where the head and the stem of nail meet. These will need to be removed and the part of the nail stem here the wheel will have contact will need to polished smooth.
Our Pack has a “KIT” that can be checked out for 24 hours by people making cars. This kit has tools that help correct the problems that the wheels and axels can have. This kit also allows all the boys to have equal access to having a “FAST” car.
This is a mandrel that holds a wheel on to a drill. While the wheel is spinning, hold a piece of sand paper to the flat side of the wheel (where the wheel meets the track) to remove any seams and any divots that may be on the wheel.
This is an axel press. The nails used for axels are just that, nails, and they are not straight. We use this press to make our axels straight. You put the axel in the axel press; then mark the head of the nail with a permanent marker. Turn the press on its side and rap it 2-4 times with a hammer. Rotate the nail head 40°, rap. Rotate the nail head another 40°, rap. Do this to the other 3 axels.
These are polishing tools for the axels. Put your axel in the drill. Use the square file and while the axel is spinning, use the file to remove any major burrs.
There are 4 different grits of sand paper, 120, 140, 180 and 220. Start with the coarsest sand paper, get it lightly wet, wrap it around the axel and holding tight, turn on the drill and run the sandpaper up and down the length of the exposed axel shaft. Repeat with each grade of sand paper, going from coarsest to finest.
The last thing to do is to take a piece of terry cloth and wet it, apply a bit of pumice. Wrap it around the axel shaft and run it up and down the shaft while it is spinning. This is the final polish. Repeat all polishing steps with the other three axels.
Place your wheels on the axels, and gently tap them into the axel channel. Do this with all four wheels. Oh no, I have a problem. One of my wheels won’t stay in place. What to do, what to do! Light Bulb! Sugru! I even have black. I made sure all 4 wheels were exactly where I wanted them, they spun freely without any friction hot spots.
I opened a pack of Sugru, warmed it up, and made two small snakes
I pushed the Sugru into the axel channels with my fingers. I used the box knife to remove any that might get in the way of the wheels. I let it dry for 24 hours as directed. Final car weight in was 138 grams.
Now, I rarely win many races, in spite of all my efforts, and I really don’t expect to do any better this year. But this year I will have the hottest looking car there! Woot!