Pinewood Derby

[CSEMARTIN]

It's my kid's first pinewood derby.

Do any of you guys have any tips?

[jhgtyre]

It's my kid's first pinewood derby.

Do any of you guys have any tips?

Yeah, help him out! My dad let me build my own. It was, well, sad to say the least. Are the cars supposed to pull to one side like that?

Have fun. I know your kid will.

-ld

[ajg308]

Rub toothpaste on the nails/axles before you install them. My little brother did this with a very plain car and won 3 derbies in a row. Dunno what it does, but it works. Wish I knew that trick.

[CSEMARTIN]

It's my kid's first pinewood derby.

Do any of you guys have any tips?

Yeah, help him out! My dad let me build my own. It was, well, sad to say the least. Are the cars supposed to pull to one side like that?

Have fun. I know your kid will.

-ld

My dad built mine and it got disqualified! He did it his way alright. No rulebook for him.

I got to watch that year.

[Jim Norman]

Don't build the car for him, help him build it.

Follow the rules, but read them carefully.

Polish is good, graphite is probably still against the rules.

Jim

[ajg308]

Don't build the car for him, help him build it.

Follow the rules, but read them carefully.

Polish is good, graphite is probably still against the rules.

Jim

I'm telling you man, toothpaste!

[JimmyZip]

Rub toothpaste on the nails/axles before you install them. My little brother did this with a very plain car and won 3 derbies in a row. Dunno what it does, but it works. Wish I knew that trick.

The abrasive in the toothpaste is very fine and will polish the axles making for very smooth running. I used to use it for polishing acrylic sculpture. Smells and works great.

[nashvillebill]

My only pine wood derby experience would not help very much. I carved and I painted this complex psychedelic looking multi colored work of art (to an 11 year old in 1973) and I was so proud. One of the wheels came in the first heat. The kid down the street spray painted his unsanded blank block, stuck the wheels on it and took first place. I am still a little bitter.

[chefcs5]

low profile. lead weights and graphite powder

[IC_Cyclone]

My experience with pinewood derby...coming from multiple wins as a cub scout and webelo and my son having won a couple times:

It's (mostly) about the kids. That said, the kids, especially the first year when their skill level is low, are mostly concerned about how the car looks. My dad let me, and I let my son, have complete control over how the car looked. Some kids show up with cars that they obvoiusly never touched. The adult needs to rough out the shape with the power tools, and then the rasping, sanding, paint, stickers, glue-on army men...it's the kids car. How it looks has nearly zero effect on performance. The only item in regard to the shape is the leading edge. Most tracks starting device consists of a bar that drops away at the front of the car. The higher the contact point on the car, the sooner the car begins to move. So a low "nose" can be a disadvantage.

OK, so the the scout worked on it, the car looks like a child built it, and he has pride in his car.

No reason not to win, too. Have your son mostly observe these steps first year, learn what to do and why. By Webelos he should be doing most of the work.

Weight, axles and alignment are everything. Get it up to maximum weight. If you have a precision scale use it and volunteer to be the weighmaster for the race. That way you'll know you can be at the maxuimum allowable weight at weigh in. If a different, less accurate scale is used at the race, you may end up having to drill away weight or be at a disadvantage to heavier cars.

Axles and wheels: Put an axle in a wheel and note the contact area between each. You'll want to minimize the contact (friction) by having the axle contact the wheel only at the innermost and outermost points on the wheel. Put the axles in a drill chuck. Use a file to reduce the axle diameter, and therefore the contact area between these points. Still spinning the axle in the drill, use progerssively finer papers and polish to smooth the axles. Be sure to smooth and polish the inside face of the axle hub where it contacts the outer face of the wheel. This can be rough and have some sharp flashing that needs to be removed. Purchase a bolt the diameter of the hub, two washers and a nut. Use these to clamp the wheel in the drill so you can spin it. Use progessively finer papers to smooth and polish the wheels. We also drilled out holes in the wheels to reduce rotational mass as the wheel begins to turn. Probably overkill. Different wheels and axles will perfom better and worse than others. We usually used 2 kits and prepared all 8 wheels and axles and tested each with a "calibrated" spin to see which 4 spun the longest and used those. The "calibrated" spin is analogous to the "125 PF knuckle" tap for falling steel. The wheels should spin and spin and spin and spin for what seems like an impossibly long time, coming to a long smooth stop. A abrupt "braking" type stop means too much friction. And graphite was legal in our pack...its what everyone used. Only dry lubricants were allowed. Check your rules carefully.

Finally, the car must run perfectly straight or it will scrub off significant speed rubbing against the track edges (or center rail depending on the track style). There are jigs that are sold, but we found that the best method is trial and error just rolling the car on a level hard surface until it tracks straight and true. Some set up their cars to run on three wheels (one wheel just hangs in the air) to reduce friction. We never did this, just too hard to get set up and keep aligned through multiple runs.

Have a great time with you son. Be careful though. This is one of those activities that involves competition, cool equipment, and mechanical tinkering.

Apparently some people are predisposed to getting caught up in activites like that.

PM me with questions if you have any...

Edited December 19, 2009 by IC_Cyclone

[jar]

A friend of mine is a scoutmaster and one thing his pack does that I thought was cool was: After all the kids are done, they have a race for cars built by the parents. This gives the parents a chance to exercise their competitiveness without affecting the kids, and it keeps more of the parents from taking too strong a role in 'helping'.

[GentlemanJim]

Cyclone has all the good info

Two sons in scouts ...countless pinewoods among other vehicles

Most important thing is to have fun together!!

Trust me...they grow up VERY fast

Jim

[Greg Bell]

My dad was never much of a handy man, but he helped build my car. It didn't roll worth a damn but it looked good. Thanks! this thread brought back a nice little memory.

[CSEMARTIN]

Thanks a lot guys for all the help.

We have a meeting in the morning to go over things. This will be all about the boy. I'm going to do my best to let him do as much as he can, but he's seven, and unfortunately, has my patience level.

It's weird how fast time flies. I'm 37 and it seems like it was just yesterday that I was the cubscout.

[bofe954]

Can you tilt the wheels? I was thinking about these the other day and wondering if you could tilt the wheels, kind of like a racing wheelchair. Maybe it would make a smaller contact patch where the wheel hits the board and add some stability.

Post a pic.

[mpolans]

Powdered graphite on the axles. On the inside face of the wheels (looking at the axle hole) we took a dremel and shaved the area around the axle hole to minimize the amount of plastic that might contact the body of the car.

Incidentally, one of my designs had a catamaran-like shape with a hollow in the very front of the car. I was told I had to fill this space up with putty or I'd be disqualified as the hollow allowed the car to start about an inch ahead of everyone else (wasn't my intention, I just thought it looked cool).

We drilled holes into the car body and used bullets for weights, then sealed the holes with candle wax.

Some places are starting to have a parent class in addition to the kids in order to let the parents have some fun without taking over their kids' cars.

[alellis]

Could somebody post a set of rules.

al

[marmax]

This site has a lot of info on it with lots of designs. Have fun and let your scout do the work. Just help him be safe..

http://www.scoutorama.com/derby/

[Get'em Duck]

make the front a little heavier then the rear..... but don't get too carried away.

As everyone said above let the kids build it it wil be more fun for all.

And graphite on the axles works wonders.

Best of luck post pics when it's all over

[mpeltier]

When my son was in scouts we built one together. We sanded, and polished and weighted, and adjusted till it was what we thought was perfect and unbeatable. The shape was like a 1954 ferrari race car. coolest looking car there, and thats the only award we won. All the winners had cars that were cut to the slimmest wedge shape and nothing more. They did not look like much but were fast.

[J-Ho]

Screw disqualification!!!!! I say mount a handful of model rocket engines on it. Go out with a little style.

[sarnburg]

Screw disqualification!!!!! I say mount a handful of model rocket engines on it. Go out with a little style.

We tried that set the track on fire during practice run.

If you have access to a lathe turn the wheels so they are true round. We also turned the wheels down so that there was a narrow contact strip in center that touched the track. Use a flat surface to make sure your wheels run true and and level, we used a piece of glass on the pool table. The write up above on axles is great we did not go that far just used a buffing wheel and polished them to a mirror finish. Double check the axle grooves we had several that were not cut perpendicular to each other.

[Matt Cheely]

As stated above, it's all in the wheels. Alignment and polish the heck out of the "axles". Other than that, let him do anything he wants to the rest of the car.

[CSEMARTIN]

Rematch this Saturday. We got our asses kicked last year. This year we're getting some payback.

[GentlemanJim]

ROFLMAO

Makes me smile that you are still having the time of your life

GET EM!

Jim