How to Make
Pinewoood Derby Cars

Pinewood Derby How-To Guide

Simple steps for a fun, legal, race-ready car

The Pinewood Derby is about learning, building, and having fun. This guide walks Scouts and parents through the process step by step, without overcomplicating it. Adults can help, but the Scout should do as much of the work as possible. Cars must be made by the Scout in the current year.

SEE BELOW FOR RULES AND GUIDELINES THEN A STEP BY STEP GUIDE TO BUILD YOUR CHILD'S CAR

Two great videos for beginners are by Mark Rober and Eng Workshop

Please follow these safety guidelines:

Wear protective goggles, gloves and a dust mask to protect your eyes, hands and lungs

Lead is often used for weight. If you use lead, wear gloves and wash your hands after use. Do not melt lead. It is toxic.

Children should not use power tools without adult supervision

If this is your first time building a pinewood derby car, we suggest starting out with a simple design requiring only a few cuts of the block.

Step 1: Start With the Official Kit

Each Scout must use an official BSA Pinewood Derby kit provided by the Pack.

The kit includes:

A wooden car block
Four wheels
Four axles

Only official BSA parts may be used.

The first step is to inspect the block, wheels and axles. If a part is defective, it is far better to replace it than to try to fix it.

Step 2: Design Your Car

Before cutting anything, decide what your car will look like.

Good design tips:

Keep it simple
A low, smooth shape usually goes faster
Make sure the front of the car is flat, this is required for the starting post
Avoid thin or fragile pieces that could break

Sketch it out or talk it through before building.

Step 3: Shape the Car

Draw your design on the wood block with a pencil on one side
Cut the shape using a hand saw or coping saw, adults may help with power tools
Sand the car smooth, starting with rough sandpaper and finishing with fine grit
The front of the car must have a FLAT edge to accommodate the starting post.
No part of the car may extend past the starting post.
Adding fenders or parts to the sides is fine, so long as they don’t exceed the maximum width.

Make sure the final size does not exceed:

7 inches long
2¾ inches wide (including the wheels)
4 inches tall

Step 4: Add Weight Carefully

The maximum weight is 141.7 grams (5.0 ounces) on the official race scale. Do not go over, even slightly!

Helpful tips:

Add weight gradually
Weigh often
Tungsten or lead weights are fine
Secure weights inside the car or firmly attached

You can always add weight, but removing it at check-in is stressful

Step 5: Wheels and Axles (Very Important)

Rules to remember:

All four wheels must touch the track
No 3-wheelers
No canted axles
Wheels must roll freely

Allowed:

Light sanding and polishing of axles (the nails) to remove mold bumps
Removing mold marks from wheels with fine sandpaper
Replacement wheels for color/style are allowed, but they MUST be official BSA wheels
Polishing wheels
Coned hubs are allowed
New axle holes and differing wheelbases
The BSA logo and wheel beading must be visible.

Not allowed:

No wheel bearings, washers, bushings, or hubcaps
No grooved or machined axles
No thinning, rounding, or reducing wheel weight
No third-party wheels or axles (BSA only
No motors, springs, or other mechanics to propel the car
Wheels modified beyond what a Scout can reasonably do WILL NOT BE ALLOWED TO RACE.

Step 6: Axle Placement and Clearance

New axle holes and different wheelbases are allowed
Wheels must be at least 1 5/8 inches apart
The car must have at least 3/8 inch clearance underneath to clear the track
The car must be free-rolling with no springs or moving devices

Step 7: Paint and Decorate

Paint and decorate however you like, just stay within size limits.

Helpful tips:

Paint before installing wheels and axles
Let paint fully dry
Stickers and decals are fine
Decorations cannot extend past the front starting edge

Step 8: Lubrication

Only dry lubricants are allowed.

Allowed:

Graphite or similar dry lubricant

Not allowed:

Oil or liquid lubricants
Anything that could drip or get on the track

All lubricant must stay on the car.

Step 9: Final Check Before Race Day

Before bringing your car to check-in, confirm:

Weight is 5.0 oz or less
Car rolls freely
All four wheels touch and roll
Front edge is flat
Nothing extends past the starting post
All parts are official BSA parts

If it passes inspection, it races.

Most Important Reminder

This is not about perfection or winning.

It’s about:

Learning new skills
Building confidence
Spending time together
Having fun as a Pack

Do your best, help when needed, and enjoy race day.

First Step - Check the Pinewood Derby Car Parts

The block

1. Inspect the pinewood derby block for cracks and chips. The block should be replaced if you find cracks near the axle slots or chips on the slots. You should also replace the block if there are any cracks that won't be removed when you shape your car.

2. Check for a warped block. Place the block on a flat surface such as a kitchen counter. Push down on each corner of the block in turn with your finger. The block should not rock. Turn the block on its side and test the corners again.

3. Check that the axle grooves are perpendicular to the block side. Place a credit card on the bottom of the block. Line the long edge of the credit card with the side of the block then compare the short edge of the credit card with the axle slot. The credit card edge should line up with the axle slot. Check the other slot. If either slot isn't perpendicular with the edge of the block, your car won't roll straight. Either get another block or drill axle holes (if your rules allow).

The Axles

1. Inspect the axles for defects. Reject any that are bad.

2. Axles should be straight. Mount each axle in a drill and spin it. If the head wobbles, the axle should be replaced or you can use our nail press to straighten the axle.

3. Pinewood derby axles have burrs and crimp marks that should be removed then the axle should be polished to give your car more speed.

4. Use a jeweler's file to remove the crimp marks and burrs.

Do this by mounting the axle in a drill then spin it while holding the file on the axle. First, place the file on the crimp marks until they are flush with the axle shaft. Then move the file to the inside of the axle head and remove the two burrs. Next, tilt the file a few degrees and press the file against the axle head to give the head a slight taper.

This will reduce the contact area between the axle head and wheel giving you more speed.

5. Polish the axles. You will need 400 grit and 1200 grit sandpaper and a polishing paste. See our full instructions for polishing the axles.

The Wheels

Mount each wheel on one of the axles that you prepared in the above step then spin the wheel. Reject it if the wheel noticeably wobbles from side to side or if it only spins for a few seconds. Roll each wheel on a flat, dry, clean surface. The wheel should roll in a straight line and not wobble. Reject any that follow a curved path or that wobble.

You can make the wheels faster by sanding the tread area to remove high marks and other imperfections and by removing the step from the outer hub (removing the hub step is illegal in pinewood derby races).

You are now ready to start working on your car block.

Design your Pinewood Derby Car

The first step is to have fun thinking up a car design. Don’t limit your child's imagination, but keep in mind that the more complicated the design, the harder it will be to shape your car. Just make sure you stay inside the size requirements and clearance.

An easy design is to cut your car in a wedge shape

Before cutting your car, try different designs on paper until you have one that you like then trace the design on the block. First, make several outlines of the side of the block on a piece of paper and make marks where the axles will go. Now you can draw your car designs inside the tracing. You will notice that the axle slots have different spacings from the end of the block. The axle closest to the end of the block should be the rear axle.

A few general design guidelines:

If you plan on inserting weights in your car (most cars will need additional weight), design your car with enough wood in the back to accommodate the weights or design your car so that the weights can be attached to the outside of the block.

Leave at least 1/4" of wood on both sides of the axle slots to prevent cracking when inserting the axles.

The front of the car should not come to a sharp point. Leave at least a 1/2" flat area on the front for the starting pin to rest against.

Curves look nice but they are harder to cut. If you only have basic tools, it is better to use only straight lines.

Here are a few sample designs to get you started.

Download and print Here are more ideas

When you've decided on a design that you like, cut the design from the paper. Place the design on the side of the block (make sure that the axle marks on the design line up with the axle slots in the block) then trace around the design. Move the design to the other side of the block and trace it again.

Cut your Pinewood Derby Block

There are several ways to cut the block of wood. The easiest is to use a band saw. If you don't know anyone with a band saw, you might be able to bring your block into a hardware store and ask them if they will cut it for you on one of their demonstration saws.

The following procedure is if you will be using a hand saw. We recommend securing the block of wood in a vise or to a bench with clamps. This is not only safer, but it will be faster and easier for the saw to go through the wood. For a single, basic cut, any handsaw will do. For more intricate cuts, use a coping saw which can cut curves. When cutting the block, hold the saw so that it cuts straight through the block and the cut follows the trace marks on both sides of the block.

Shaping your Block

After your block is cut, you can further shape it and round the corners by using a wood rasp. A rasp is a great tool for shaping your car. Once again, be sure to wear protective gloves and a face mask so you do not inhale sawdust.

To smooth your car, you can use a metal file and different grades of sandpaper. Start with a course grade of sandpaper - around 80 grit - and finish up with a fine grade of 160.

Adding weights to your Pinewood Derby Car

The heaver your pinewood derby car is, the faster it will go so you want your car to weigh right up to the 5 oz limit. You can use just about any metal object for weights. You can glue the weights to the outside of the car or drill holes and insert the weights inside the car. It is best to add the weights near the back of the car for an extra speed boost. The height of the weight will not make a difference to your car's speed. If you drill holes in the car for weights, you can use wood putty to seal the holes. Wood putty will require several hours to dry. If you are in a hurry, you can use a hot glue gun or super glue.

You can put weights under your car as long as there is still at least 3/8" clearance between the bottom of the weight and the track.

If you don't have an accurate scale, we will have scales available to members of the Pack on cutting days. If you plan on gluing parts to you car, be sure to weigh the parts with the car.

Painting your Pinewood Derby Car

You are now ready for the final touches: painting, decals, and decorating. First, make sure that the car feels smooth to the touch. Sand it if it doesn't. Painting can get messy.

Try to not paint the area around the axle slot as shown in the picture. This area will be coated with graphite later.

After the last coat of paint dries, you can add decals, racing stripes or paint designs on the car. You can also glue on pieces of toys, like toy soldiers, car parts and so on. It's a good idea to use a final clear coat of paint if you are using racing stripes or decals. Paint the clear after the extra items have been added to the car.

Adding Wheels and Axles

You are now ready to add wheels and axles to your pinewood derby car. First, you should lubricate the car and wheels with graphite.

First we want to reduce the friction between the wheel hub and the car block. Sand the area around each axle slot with 400 to 1000 grit sand paper until smooth. Pour a small amount of graphite on a clean sheet of paper. Grind the end of a pencil eraser in the graphite (you can also use a Q-tip). Then apply the graphite to the car body by grinding the eraser into the area around each axle slot as show above. Add until the area is saturated with graphite.

Next are the wheels. Add more graphite to the sheet of paper if needed then rub the wheel hub into the graphite until you have a shiny ring of graphite around the wheel hub.

Rub the Q-tip in the graphite then rub on the wheel outer bore until the area around the bore is shiny.

Next you want to work as much graphite into the wheel bore as possible.

1. Clean the wheel bore (hole). Run a clean pipe cleaner through the hole several times. Do this for each wheel. When done,

Sprinkle some graphite on the pipe cleaner and run it through each wheel several times adding graphite often.

2. Stack the wheels on top of each other.

3. Plug the bottom wheel hole with your finger then pour a few puffs of graphite into the top hole.

4. Plug the top wheel hole with your thumb then shake the wheels several times.

5. Pour any loose graphite out of the wheel holes.

6. Insert an axle part way into a wheel. Pour a few puffs of graphite into the other end of the wheel.

Slowly push the axle up through the hole while shaking and turning the wheel to work as much graphite as possible between the wheel and axle.

7. After the axle has been pushed all the way through the wheel, work more graphite between the wheel and axle by pouring more graphite between the wheel and axle, moving the axle up and down and spinning and taping the wheel..

8. Mount the wheels on the car. The axles should be inserted as high in the slot as possible and should go straight in perpendicular to the block. Push the axle in until there is a credit card thickness gap between the wheel and block.

When all four wheels are on the car, push the car forward on a flat surface. It should roll within two inches of straight for a three foot run. If the car doesn't roll straight, one of the wheels is pulling the car to the side. Remove one of the front wheels. Roll the car again. If it rolls straight then you know that the removed wheel is causing the problem.

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How to Make Pinewoood Derby Cars