Pinewood Derby Car Showcase – October 31, 2014

Today’s cars are owned by Darren Stark.

“I started a collection of pinewood derby cars and now have close to eighty. Sixty-five to seventy of them I personally built with family and friends. The photos below show a few of my favorites.

My son and I go to several races every year and display our cars with Todd Paxson. Todd is a friend of mine whos cars were used to make the movie “Down and Derby”. He is the one who convinced me to display my cars rather than keep them in a box. My son and I get such a kick out of watching people’s reactions to our cars and helping others figure out how they can make their ideas come to life. I hope you like them as much as we do

Editor’s Note: Todd Paxson’s display was featured in
Volume 6, Issue 14.

From Pinewood Derby Times Volume 14, Issue 2

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Maximum Velocity Pinewood Derby Car Plans and Supplies

Creating Accurate Pinewood Derby Axle Slots

By Randy Davis

Most brands of pinewood derby kits come with slots on one side of the block into which the axles are pressed. These pre-made slots generally work well, but there are occasions when the car builder would like to cut new axle slots. These include when:

1. The existing slots are defective.
2. The builder wishes to change the wheelbase by cutting new slots on the opposite side of the block.
3. The builder wishes to build two cars from one block by cutting new slots on the opposite side of the block.

Previously, cutting new slots was a bit tricky. Usually, a hacksaw was equipped with two blades, and then the builder carefully cut new slots by following a pencil line. Obviously, errors were common: cutting a slanted line or cutting too deep were common issues.

But now, a new tool is available to solve these issues and greatly simplify the process of cutting new slots.

DerbyWorx recently introduced the Pro-Body Slotter. Similar to the Pro-Body Tool for drilling accurate axle holes, the Pro-Body Slotter is a cutting guide for cutting axle slots.

Figure 1 – Pro-Body Slotter

The tool fits over a standard pinewood derby block, and is held in place with a set screw (a clamp would interfere with sawing). Index marks on the tool are aligned with a pencil mark on the block which identifies the desired location of the new slot.

Figure 2 – Pro-Body Slotter Parts

Figure 3 – Pro-Body Slotter Parts

As mentioned before, two hacksaw blades are mounted on a hacksaw frame (one blade is mounted with the teeth forward and the other with the teeth reversed. The blades are then placed into the slot in the tool, and the cut is made.

After the first cut is complete, the tool is loosened, moved to the next slot position, reattached, and then the second cut is made.

Figure 4 – Pro-Body Slotter in Use

The index screw will leave two indents in the block, one per slot. These marks are filled with wood filler before sanding and painting. Note that the marks will be located behind the wheels, so they are not obvious.

Here are a few tips for using the Pro-Body Slotter.

1. Use the Pro-Body Slotter on the pinewood derby block before cutting or shaping the block.

2. When placing the tool onto the block, orient the set screw on the side of the block opposite the pencil marks.

3. Keep the set screw on the same side of the block for both cuts.

4. Use even, gentle forward and back sawing strokes.

5. Make sure to stop when the saw blades reach the bottom of the tool.

6. For an extended wheelbase, position the slots at 5/8 inch (actually I prefer 11/16 inch) from each end of the block.

7. After cutting the slots, use a Pro-Axle Guide to insert a spare axle into each slot position, then twist and pull it out with a pair of pliers.

8. When painting, either mask off the axle slots, insert a spare set of axles into the axle slots, or better yet, use a Paint Stand.(1)

Using the Pro-Body Slotter makes creating accurate axle slots a simple process. The Pro-Body Slotter is available from many on-line vendors including Maximum Velocity. You can find the tool Here. A video from DerbyWorx on using the Pro-Body Slotter is available Here.

(1) The Paint Stand is available from Maximum Velocity Here.

From Pinewood Derby Times Volume 14, Issue 2

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Maximum Velocity Pinewood Derby Car Plans and Supplies

Pinewood Derby Car Showcase – October 16, 2014

Let’s kick off the new season with some very unique cars that were submitted at the end of last season.

’56 Ford Pickups – Lyle and Ben Leis

2009 was the last year for my son to compete in the Pinewood Derby. He has done well in the past with a variety of cars, but for his last year, he wanted to build a pickup truck. We bought a ’56 Ford Step side die cast car to copy and scratch built from there. Since we only had two weeks to get them completed, it was an ambitious project.

In the past, I have built several exhibition cars while my son built more conventional cars. Using the profile of the die cast car, we started with a sketch of the top and side view of the car using the Boy Scout wheelbase and overall dimensional requirements. Since this project required a hollow body and woodcarving skills, we each built a truck with me working step by step ahead of my son while he followed/copied my work on his truck. The original Pinewood block was cut down to 3/8 inch thick and thin pine stock was added to form the bed and truck cab. The panels were carved and sanded to final shape followed by many coats of primer with sanding between. Since the colors are transparent, a silver base coat was used under the transparent top coats. The hollow lead tanks in the rear of the beds are formed from stick on wheel weights and final weight adjustment was made using lead shot. A wood screw between the truck bed and the cab secures the cab to the chassis.

Although the truck didn’t do well in the race due to aerodynamic considerations, for the first time my son has taken an interest in woodcarving, so I consider it a huge success. His truck also won a trophy for the Most Unique design, although the judges were probably not aware of the hollow cab and woodcarving required for the build.

The first photo shows the cab off and the second shows the underside of the cab and how it was scratch built from pieces of pine before final shaping and painting. My son’s truck is blue and mine is red.

Monster High – Damon and Addison Krall

This Monster High-heeled Shoe car was built for fun for my daughter Addison to beat all the boys at her brother’s derby on race day. The speedy razor wheels gave this car a nice boost. The unique design got
lots of attention.

Landspeeder – Dennis Bjorn

While sorting through my adult son’s Legos I found the instructions for a Lego version of Luke Skywalker’s Landspeeder. After consulting with Obi Wan and Luke we decided my speeder could only have one seat, so it wouldn’t interfere with the cars in the other lanes. Obi Wan found a guy that could machine the three-spoke wheels.

From Pinewood Derby Times Volume 14, Issue 1

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Maximum Velocity Pinewood Derby Car Plans and Supplies

Revisiting the Balance Point

By Randy Davis

In my first few pinewood derbies I had no concept of setting a balance point (also known as COG or CG). I knew that the car needed to weigh five ounces, so I added weight to the middle of the car and raced. We had mixed results (most everyone else didn’t know what they were doing either). But there was one family who had very fast cars. From that Dad, I learned about rear-weighting (and about using a quality graphite). So after that we started rear-weighting the cars.

When I wrote the first few editions of our “Speed to the Finish” booklet (for free distribution at our local club – not for sale) I didn’t even mention a balance point. But in the first edition that went on sale, I gave a range of 3/4 to 1-1/4 inches as the target balance point.

Although I don’t believe my booklet really set the standard, somehow a 1-1/4 inch balance point became the de facto oral standard for the balance point. Even today, I regularly get calls from folks who state that they “set the balance point of their car to 1-1/4 inches, which is the recommended position”.

Is/was a 1-1/4 inch balance point the best position? Has anything changed to cause us to rethink the best balance point? Let’s take a deeper look.

The balance point of a pinewood derby car can be easily located as follows: (1) set a balance stand (or a ruler on its long edge) on a table and (2) lay the car (with wheels and axles in place) on the device as shown in Figure 1. Move the car forward or backward until it balances on the ruler. The balance point is the distance from the
center of the rear axle to the point at which the car balances.

Figure 1 – Locating the COG

The balance point directly affects the stability of the car. If a car has a balance point that is too aggressive for the track, the car will generally be very fast on the hill, but will become unstable on the flat portion of the track and will exhibit a rapid left-right motion known as the “death rattle”. To correct the instability, either Rail- Riding(1) alignment must be implemented (or increased), or the balance point must be moved forward.

Likely, the 1-1/4 inch balance point standard came from repeated posting of this number on web sites and in speed tip booklets. At the time when this number became a standard (the year 2000 or earlier) most tracks were made of wood and were not as smooth and precise as modern tracks. So the 1-1/4 number was aggressive enough to provide good performance, but conservative enough to provide stability on the vast majority of tracks. Another factor to consider is that tungsten was not readily available for car weighting until about 2003, so making a car with a more aggressive balance point was a challenge for most car builders. So, all things considered, at the time the 1-1/4 inch balance point was a good target number for the vast majority of car builders.

But then, as always, technology changed and pinewood derby racing reaped some of the benefits. First, aluminum tracks came on the market, followed quickly by tungsten weight. Now, cars could be more easily rear-weighted, and smooth tracks were available to improve stability. Finally, the Rail-Riding alignment method was introduced to the pinewood derby community, which provided increased stability for cars running with aggressive balance points.

So, we are now at a time when the 1-1/4 inch standard is a bit dated. When people ask, I now give the target balance point numbers listed below. Please recognize that these numbers are for people that generally do not have tracks to test on and have one shot at racing. Certainly, you can be more aggressive if you have access to a track, and time to fine tune the car.

Wood Track, no alignment consideration: 1-1/4 inches
Wood Track, Rail-Riding: 1 inch
Aluminum track, no alignment consideration: 7/8 inch
Aluminum track, Rail-Riding: 3/4 inch

There are other factors that affect these target numbers. For example, tracks of 50 feet or longer, and very rough tracks require a less aggressive balance point. But if the track is reasonably smooth and of a standard length, these target balance point numbers work well for the majority of car builders.

Certainly there are a lot of factors that affect the positioning of the balance point. However, I hope that this article provides some food for thought, and helps reset the standard for setting the balance point. But I am sure that I will keep getting calls from folks stating that they “set the balance point of their car to 1-1/4 inches, which is the recommended position”.

(1) Rail-Riding is an alignment technique that generally improves performance. In November, there will be a complete article on Rail-Riding.

From Pinewood Derby Times Volume 14, Issue 1

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Maximum Velocity Pinewood Derby Car Plans and Supplies

Pinewood Derby Car Showcase – October 3, 2014

Today’s showcase cars are from Chad Thorvilson.

I have been involved in the Cub Scouts since my son, Ryan, first started in 2000. The second year of the pinewood derby I made a new four lane Formica track for the pack. He is now in Boy Scouts, and he and I still help run the track. We have always enjoyed making cars and other projects in the shop. We no longer race, but we still make cars every year. The last few years I have been making trick cars.

This white and red car has a trigger on the bottom that releases the sides and roof. A small wedge is put on the track and when the car crosses it the sides and roof pop off.

The light blue speckled car leaves the cab behind as the tires and frame go down the track.

This blue car has a piece of radio antenna that I pull out to hold the competition back.

The red and blue car has a nose attached to a radio antenna. I pull out the nose and tell the boys that I will beat them by this much.

I also have a car with a small motor geared to the tire to make it run very slow (not shown).

Here is my fan powered car and string/motor car.

We have also made some nice cars. We were finalists in the Lowes/Dremel contest one year and grand prize winners the last year they had the contest.

We look forward every year to the pinewood derby and working in the shop together. I get excited when the first Pinewood Derby Times arrives in my inbox.

From Pinewood Derby Times Volume 8, Issue 7

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Maximum Velocity Pinewood Derby Car Plans and Supplies