Steindorf’s Pinewood Derby Speed Tips
Dec-2010
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BASICS
 Have fun. Use the derby as learning and bonding opportunity.
LEARNING QUESTIONS…
 If you drop Ping-Pong ball and golf ball at the same time,
which hits the ground first?
o They’ll hit about the same, golf ball might hit first due to air
drag on Ping-Pong ball. On the moon they’d hit at the
same time, because there’s no air friction.
 Which would hurt more, a golf ball dropped from waist height onto your foot, or a golf ball dropped from head
height onto your foot? Why?
o The longer the fall, the more energy (faster) the ball/car will have, so higher would hurt more. See the
WEIGHT section below for why this is relevant.
 If you roll Ping-Pong ball and golf ball down derby track, which one will roll the farthest before it stops?
o Golf ball, because it is heavier and has more inertia and therefore wants to keep rolling more.
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Minimize Friction
o Wheel–axle (debur and polish the axle, graphite the axles)
o Wheel–track (align axles so car runs straight; smooth and polish the treads)
o Wheel-car body (cone the inside of the wheel’s hub, hard smooth finish on car body, hubcaps)
o Vibration (smooth spinning wheels; long wheelbase; weight not too far back)
o Air drag (aerodynamic design)
Maximize inertia (object doesn’t want to change its motion, either stay stopped or keep moving, and inertia is
a function of weight). Inertia is what keeps the car going once it hits the level portion of the track.
o Maximize weight
o Weight as far back as possible while maintaining stability (center of gravity about 1” in front of rear
wheels). Since the car is at an angle in the starting block, the further back the weight, the farther it falls
and the more energy it has.
LINKS
Google “pinewood derby” for lots of links.
http://members.aol.com/StanDCmr/lbw_apl.htm (Stan Pope’s book on Derby Car Building – lots of other good
technical data by Stan on this site)
http://members.aol.com/randywoo/pine/ (a good pinewood derby site)
http://www.maximum-velocity.com/ (a retail site. Join their email list for great articles)
http://www.abc-pinewood-derby.com/index.htm (retail site)
TOOLS:
(Needed for Beginner and Advanced craftsmen)
BASIC TOOLS
 Rules for your derby(s)
 Saws, knives, files and
sandpaper for shaping
 Paint
 Weights
 Fine triangular file (Lowes)
 Magnifying glass
 400 and 600 grit wet/dry
sandpaper
 Super fine graphite
 Square (Playing card)
 Power Drill
 #44 drill bit
 Post office scale or Derby
scale
 Scissor
 Glue (I prefer Duco)
 Masking tape
TOOLS FOR MORE ADVANCED WORK
 Dremel tool
 Axle Hole Guide
 Drill Press
 Band Saw
 Metal polishing rouge
 0000 steel wool
 Wheel Mandrel (Michaels,
Hobby Lobby, Scout shop)
 Playing cards (for hubcaps)
 1” hole punch (for hubcaps)
 PVC Cement
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Dec-2010
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HOW TO BUILD A FAST CAR
AXLE SLOTS (perpendicular to the body)
 The slots need to be parallel to each other and perpendicular to the car body to keep the car running
straight.
 Cutting new slots to make a longer wheel base will help with stability.
 Be careful when inserting the nails in the slots to avoid damaging them or causing the nails to go in crooked.
It’s best to pre-drill holes in the slots with a #44 bit for the nails
TIP - It will help reduce friction if on of the front wheel is about 1/8”off the track.
BASIC
Tools: Playing card, drill with #44 bit
(WoodCrafters?), hand saw
 Use a playing card, square or drafting
triangle to check alignment of slots to edge
of car body.
ADVANCED
Pro-Body Axle tool if available.
Band saw and/or drill press with #44 drill bits
 If you have a Pro-Body Axle tool, use it per the
instructions.
or
 Use a band saw or drill press to cut new axle slots half a
 If one edge is more than 1/16” off, either
wheel length from the ends of the body (long wheel base if
carefully cut a new slot using a square as a
allowed). Slots should be the same size and depth as the
guide or at least make a note of it so you
originals.
can adjust the axles.
 Make test cuts first to make sure the equipment is aligned
square.
With the #44 drill bit, carefully drill out the slot from the side to make the nail go in the slot properly and to
prevent splitting the wood.
TIP – One front wheel should be 1/16-1/8” higher (off the floor) so it won’t touch the track
NOTE – Although I have not used it, the Pro-Body axle tool sold on the Maximum Velocity website would be a
good investment, certainly for pack construction clinics. It comes with the needed #44 drill bit and simplifies axle
slot alignment.
CAR BODY (DESIGN)
 Come up with a fun shape, that’s within your skill range.
 Aerodynamics aren’t critical, but you don’t want any create any air brakes (funnels)
 ADD parts to get to the final shape (wood wedges, model parts, LEGOs, etc.)
 Use a coping saw, whittling, files and sanding to get to shape. For advanced shaping, a band saw or scroll
saw is great.
 Plan for a way to adjust the weight of the car(more below)
o Design it to be light and add weight when finished.
o Holes or slots, screw threads, coins
 Allow for the weight of the paint
 Lacquer paints dry faster than enamel paints.
 Use a sanding sealer or primer under the paint for an ultra-smooth finish
 Use the SAME BRAND of paints and primer to ensure compatibility
 Toothpicks in the axel slots will keep them from plugging up with paint
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Dec-2010
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WEIGHT
Points to consider:
 You want the finished car to weigh as much as allowed (5 ounces). BUT, getting it exact isn’t critical as
going over can mean a lot of work to remove weight.
 Consider how and where you can include the weight when you design your car. Drilling 3/8” holes in the car
body is one of the easiest ways to create cavities for weight cylinders.
 Design your car so its weight can be easily modified when the car is done… coins, bolt with nuts and
washers, or a cavity or drill a hole in the car that you can fill with fishing shot and seal with candle wax.
(More on weights below)
 Paint and finishing have weight.
 It’s easier to add weight when done than remove it.
 Generally, the center of gravity should be about 1” in front of the rear axle slot. 1.5” for racing on a track with
a long flat run. Check by balancing the car on a pencil.
 You want the center of gravity back to increase the effective distance the car falls. It starts tipped at an
angle, but finishes level. The distance it falls relates to the force pushing it. Think about dropping a brick on
your foot from 1” versus from 5 feet. Which would hurt more?
 However, weight forward is more important for stability on the flat portion. You don’t want the car to be
bouncing side to side on the guide rail. The analogy here is throwing an arrow tip first versus tail first. The
light end is going to be more influenced by drag and want to follow the heavy end.
STABILITY EXPERIMENT – If you get a chance, time your car several times down the track running forward and
backward. Compare the times. Watch the car from the behind the starting gate looking for wobbling. Which way
works better with your track, weight forward or backward?
IDEAS FOR WEIGHTS:
Derby car weights (scout shop or Michaels Pine Car weights), coins, bolts and nuts, fishing weights, tire balance
weights (ask tire store for their trashed ones). The pre-made zinc weights require a hack saw to cut (difficult).
Lead fishing weights can easily be hammered into desired shapes.
Hard core weights – custom lead weight:
SAFETY FIRST – melting lead should be done by an adult and outside. Wear gloves and safety glasses. Lead
stays hot long after it looks cool.
Make a plaster mold of the shape you want. Simpler is better.
Weigh your car and pieces of lead to get to about 4.5-4.8 ounces (allows room to fine tune weight)
Using a channel lock or other large pliers, hold a tire weight by the steel center clip (wear gloves).
With a propane torch heat the end of the lead and drip it into the mold until the mold is full.
You can use a wooden stick to scrape the dirt off the pool of molten lead. Note that the mold will have rounded
edges due to the surface tension. Filing to shape is not recommended due to generation of lead dust.
Let it completely cool, remove from the mold and attach to the car.
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Dec-2010
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AXLES (nails)
The objective is to have an ultra-smooth surface for the wheel
to spin on.
 Removing the flashing is a must. A fine triangular file works
great.
 There is flashing under the head (2) on the side (3 bars)
and at the tip.
 Polish as much as possible. Try to get a mirror finish.
Plan on at least an hour to make good axles.
Tip - Do not insert a nail into any wheel until all the flashing
has been filed off. You do not want to score the inside of the wheel.
BASIC
Tools:
drill (preferably reversible),
magnifying glass
fine triangular file (hobby file),
400 and 600 grit emory paper
1200 Grit paper (optional)
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Using the magnifying glass, locate the 3 areas
of flashing on the nail: on the sides of the tip,
the bars on the shaft, and inside the nail head.
File the flashing off the sides of the nail near
the tip. Check with the magnifying glass.
Insert the nail into the drill.
Without running the drill, gently file off the bar
on the side of the nail using a rocking motion.
Now, spin the nail with the drill and press an
edge of triangular file into base of the head.
Press the flat of the file alternately against the
shaft and against the head to remove the
flashing. Reverse the drill and repeat.
Polishing
Cut several ½” wide strips of 400 and 600 grit
wet/dry sandpaper and fold them in half-length
wise to ¼” strips. Put a few of them in a bowl of
water.
Polish the shaft and inside of the head with the
strips while spinning the axles in the drill at its
highest speed. Use 400 grit then 600 grit.
Inspect with the magnifying glass.
Final polish1200 grit wet/dry sandpaper (cut in
strips and dipped in water as above)
ADVANCED
Reversible drill;
fine triangular file;
400 and 600 grit wet/dry sand paper;
dremel tool; vice or clamp to hold the dremel tool;
magnifying glass or loupe;
polishing wheel for dremel;
½” wide strips of cloth & polishing rouge (home
improvement store)
Graphite
Storage bag or film canister
Remove the flashing as in the BASIC steps.
Tip –make the nail head somewhat conical when filing to
minimize the area contacting the wheel.
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Cut ½” strips of 400 and 600 paper. Fold them in half
to ¼” and put some in water.
Mount the dremel on a vice or stand.
Mount the axle in the dremel tool.
Use wet 400 then wet 600 paper to polish the axle
shaft and head (inside and outside!)
Rub some metal rouge, a paste of pumice or Comet
onto a strip of cloth and continue polishing with the
cloth. The cloth will turn black as you go.
You should be able to get a mirror finish on your
axles.
Further polish the axle with a cloth dusted with
graphite.
Store the axles in a plastic bag or film canister to keep
them clean.
UNPROVEN IDEA:
File some circumferential notches in the axle to reduce the
surface area contact with the hub. Be careful to leave
enough surface to keep the wheel from wobbling.
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Dec-2010
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WHEELS
 Wheels are the biggest source of variability in the kit. It is very hard to compensate for bad wheels.
Therefore, the least documented secret to success for fast cars is to buy extra wheel kits and use the 4
fastest wheels.
 Wheel styles and axle diameters have changed over the years, so be careful if you are mixing and matching
from kits over several years. Skinny axles will lead to wheel vibration which will slow down your car.
 Note that turning a wheel on a lathe can improve its performance, but it won’t make a bad wheel into a good
one. So, rather than buy wheels that have been turned on a lathe, the better approach is to buy extra wheels
and pick the best 4.
Testing wheels:
The objective is to find the best 4 wheels to use.
BASIC
Tools:
Deburred and polished axle
Watch or timer
ADVANCED
Deburred and polished axle;
car body with axle slot;
micrometer
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Mount the wheel on an axle.
Hold the tip of the axle firmly and spin the wheel lightly and
then fairly hard. Be consistent with how hard you spin it.
 Time how long it takes for the wheel to stop spinning.
 Repeat this for all wheels ranking their performance. Recheck wheels if needed.
Good Characteristics:
 Wheel spins smoothly at all speeds with little visible wobble
or vibration.
 Spins a long time.
Bad Characteristics:
 Wheel makes an audible buzz with bad vibration.
 Visible wobble.
 Wheel bounces from side to side a lot.
 Stops spinning quickly.

Your fingers tend to dampen out vibration.
A better test is to spin the wheels while
mounted to a car body. Hold the body on
a table edge to keep it even more rigid.
Test the wheels as in the BASIC
instructions and use the 4 that run the
smoothest and longest.
TIP - If you are using wheels from different
years, check the diameter of the axles. There
are two axles 0.087 and 0.092” thick. Use the
largest axles if they will fit in your wheel, but
don’t force them in.
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Dec-2010
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Finishing Wheels
Objective is to smooth the tread, inside hub and outside outer edge of the wheels to reduce friction.
Tip – practice on a bad wheel
BASIC
Tools:
Drill
fine file,
fine steel wool,
400 grit emory paper,
3/16” bit
 Mount the wheel in the drill by putting the hub
in the chuck.
 Carefully file off the outside outer edge (has
little ridges) running the drill at a moderate
speed. Too fast will melt the wheel.
 You can also shape the tread of the wheel to
make it slightly concave, but this isn’t critical.
 Smooth the tread with fine steel wool then wet
400 grit sandpaper.
 File or sand the inside outer edge of the wheel.
 File or sand the inside of the hub where it will
bump against the car body.
 Remove the wheel from the drill.
Smoothing the inside of the hub
 Hold the drill bit in your right hand. Slide the
wheel onto the bit.
 Spin the wheel toward you by hand. Twist the
bit back and forth as the wheel spins.
 Take the wheel off and put it back on from the
other side. Spin it toward you again.
 An alternative is to polish the inside with a pipe
cleaner in a drill.
ADVANCED
Wheel mandrel (Michaels),
drill,
plastic rouge,
polishing cloth,
air can
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Insert the wheel on the mandrel and mount in the drill.
Smooth the wheel corners and tread using a file, steel
wool and wet 400 grit sandpaper.
Polish the wheel tread with rouge for plastic on a
cloth.
Smooth the inside of the hub as in the BASIC
instructions
Tip: Make 1” hubcaps for your wheels using a 1” diameter
adhesive label with a ¼” label stuck adhesive-to-adhesive
for the nail head to ride on. Hubcaps can keep your
wheels from rubbing on the car body if you don’t push the
axel in too far. There is friction on the nail head than the
car body, so polish the nail head.
Sturdier hubcaps can be made from playing cards and a
1” punch.
PVC cement around the perimeter of the hubcap works
well to stick it to the wheels. Be careful not to get any glue
on the axle.
Remember to put the polished axle before gluing on a
hubcap.
LUBRICATION (graphite)
 DO use super fine graphite or graphite/moly, such as Hob-E-Lube from Michaels). Graphite can be found at
lock/key cutting area of home improvement stores.
 Do NOT use the white graphite/Teflon lubricate (scout shop)
 Do NOT re-lubricate just before a race. Graphite needs to be worked in for best results. Once done, leave
the car alone.
 Lubrication is best done with the wheels on the car. But as this is messy, you can lubricate the wheels
beforehand and store them in a bag until you’re ready to put on the car.
 Keep axles and wheels mated once they’ve been lubricated.
 Silicone lubricant (GUNK brand or NyOil II found on Maximum Velocity’s website) is said to work well, but I
don’t have any experience with it and some rules may not allow it. Note – the Maximum Velocity website
suggests that pure graphite (their Tube-O-Lube) works better than graphite/moly and as well as the NyOil.
HOW:
 Blow all dust off the wheels and finished axles.
 Hold the axle vertically, so the wheel is resting on the nail head.
 Sprinkle a little graphite in the hub. Slowly rotate the wheel so the graphite gets down in the wheel.
 Now hold the axle horizontally and spin the wheel in the direction it will be spinning in the race.
 To really work in the graphite, spin the wheel with the buffing wheel on a dremel tool for about a minute.
 A couple doses of graphite and spinning and you wheel will be ready to race.
 DO NOT re-lubricate just before the race, unless you are going to really work it in by spinning again.
Steindorf’s Pinewood Derby Speed Tips
Dec-2010
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ALIGNMENT:
You do not want your car to veer to one side. This will cause it to “ride the rail” and will significantly hurt
performance.
Check your alignment early in the car building process in case you have to re-cut your slots. Then check it again
when the car is nearly finished.
Once the slots have been set and the wheels done, carefully insert the wheels into the slots. Make sure the
wheels aren’t tight against the body of the car. Put the slowest wheel in the slot that is off the ground.
The simplest alignment test is to gently roll the car on a flat surface and see how it does. You can also put it on a
board and lift one end. Roll the car forward and backwards. If it consistently pulls to one side you have a wheel
or alignment problem.
Sometimes you can simply look at the wheels and see which one is crooked.
If not, remove one wheel at a time, starting with the front wheels, and roll the car with 3 wheels. If there is just
one bad wheel, the problem is usually pretty obvious. To check the back wheels, you’ll have to add weight to the
front to keep the car on the front wheels.
Once you figure out which wheel is steering the car, you need to straighten out the slot. The trick is to make little
1/8” x 1.5” shims out of wax paper. Carefully hold the shim in place in the axle slot (front or back) such that it will
force the axle into the right direction. You might need to take the drill with the #44 bit and gently cant the slot to
help straighten things out.
Once your car runs fairly straight, glue the axles in place. I prefer to use Duco cement rather than white glue as it
grips the axle better. I also mask the slot so as to not ruin the paint job with the glue.
For a more detailed method of analyzing wheel alignment issues see:
http://www.florian.org/Kids/Scouting/PineAlign/PineAlign.html
This analysis is also outlined in Stan Pope’s web book. http://members.aol.com/StanDCmr/lbw_apl.htm
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Dec-2010
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