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Pinewood derby ideas?

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Forum topic by MashMaster posted 979 days ago 1628 views 0 times favorited 18 replies Add to Favorites Watch
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MashMaster

92 posts in 1284 days


979 days ago

My son is going to be entering his first pinewood derby this year. Does anyone have any hints/ideas for a fast car? I want to let him do as much as possible but he is only 7 so I’ll need to do some of the cutting.

-- - Dave ; Austin, TX


18 replies so far

View DS's profile

DS

2131 posts in 1045 days


#1 posted 979 days ago

  • Buy extra boxes of wheels and pins and test all of them. Pick only the best ones from the lot. Many are not true or round due to poor manufacturing.
  • Never insert a pin into the wheel before deburring it first. Otherwise you will scar the inner surface of the wheel and add friction.
  • Be sure you get as close to the 5 oz. weight as possible. Even a small amount underweight will severly reduce a cars speed.
  • HAVE FUN! The Cub Scout program is first and foremost about having fun. Fun building a car with Dad, fun racing the car with other scouts. Too serious, or too much competition will take some fun out of it for the boys, so don’t lose sight of that. (Winning, of course is fun too)

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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Gary

7082 posts in 2057 days


#2 posted 979 days ago

My son does this with my grandsons. Seems the biggest thing is to polish the axels and placement of the weight

-- Gary, DeKalb Texas only 4 miles from the mill

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brtech

664 posts in 1547 days


#3 posted 979 days ago

First Rule of Pinewood Derby – have fun.
Second Rule of Pinewood Derby – It’s the Cub’s project, not yours

On the “get close to 5 oz” issue, remember that all scales are not created equally. Plan on having some form of addable weight, start light, don’t go over. Find out what the weight in rules are like. Sometimes you only get one weigh-in, but usually, they let you play around a bit.

The pins/axels are the weak link, good advice above. Graphite lube helps a bit.

Make sure the car tracks absolutely straight.

Not sure weight distribution helps all that much, but some do.

While the race is a race, the kids seem to get a good kick out of appearance. In my experience, the finish is more important than the shape, but YMMV.

This has some more info:
http://home.simplyweb.net/bosworth/speed.htm

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Pdub

891 posts in 1804 days


#4 posted 979 days ago

My son was more concerned about the looks than the speed and last year my daughter wanted it to look like a corvette, so thats what we tried for. They were both in AWANA. Its through the church for those not familiar with it. We could always run with the pack but never ahead of the pack, so I can’t help with fast. Good luck and have FUN!!!!!!

-- Paul, North Dakota, USAF Ret.

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lysdexic

4785 posts in 1247 days


#5 posted 979 days ago

This year will be our last year. I live in Mooresville NC, the home of NASCAR. Many of the dads work for the race shops. The cars in my pack are incredibly tuned.

This book, Pinewood Derby Secrets, is a classic and will help you tremendously.

For alignment – google rail riding. It is consistent and works. I love the woodworking aspect but when it comes to the wheels and axles I buy polished. After the race, take them off replace them with the crappy ones and re-use the “race set” next year. Seriously, weve got guys who put their wheels on CNC lathe machines. We can’t compete with that. You can buy trued wheels and polished axels then spend more time on design, shaping, painting, and cool flame decals :)

KNow your packs rules before investing to much time. Start early.

The most important design and execution variables (IMO)
wheel and axle friction
alignment
center of gravity
After these it doesn’t matter that much

It is because of the pinewood derby that I am here. I had a smoldering interest in wood working for a long time. BUt when I went over the Den leaders workshop to work on my son’s car it ignited an interest that brings me here today. I’ve gone from pinewood derby car to lapping a type 11 Stanley 4 1/2. Who’d thunk it.

Best of luck and let me know if a can help.

-- It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe. - Muhammad Ali

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lysdexic

4785 posts in 1247 days


#6 posted 979 days ago

The fun vs winning is a difficult topic. If my son wants even a chance to win I have to most of the construction. I know it is your sons car but make sure it will at least get down the track We had a boy whose car couldn’t make it to the finish line. You could tell it was tough for him to walk out and retrieve it every time.

Fortunately we have a Parents and Sibling race the night before that goes up to 10 oz. My son builds his younger sisters car with minimal assist. I spend WAY too much time on mine.

-- It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe. - Muhammad Ali

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MashMaster

92 posts in 1284 days


#7 posted 979 days ago

Thanks for all the advice, I saw how to make the axles thinner and more polished I’ll do that for my son and left him draw the body template out, sand, and paint it. I’m sure we won’t be the fastest but he will have a lot of input and effort for it. Looks like I need to research the rail riding technique.

I bet in Nascar country the competition is pretty impressive.

-- - Dave ; Austin, TX

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JSilverman

87 posts in 1238 days


#8 posted 978 days ago

first be sure you know your pack rules. I am a packmaster (for the last 4 years) and we do not allow “tuned” wheels at all- it would lead to immediate disqualification of a car. That is the “official” cub scout rule. Other packs do it differently. Graphite on the axels is fine.

making sure the car tracks straight is key IMHO; so is the proper weight of the car (I personally prefer most, but not all, of the weight on the rear wheels). After that not much else matters in such a short race- let your son have fun shaping and decorating- remember do not change the width of the car at the axels or it wont fit the track properly.

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MashMaster

92 posts in 1284 days


#9 posted 978 days ago

Is it cool to polish the axels and remove burrs from the nails and wheels? What constitutes “tuned” wheels.

-- - Dave ; Austin, TX

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lysdexic

4785 posts in 1247 days


#10 posted 978 days ago

Great question.

Depends on your pack. JS probably knows better but our pack does not allow wheels that are not the Official BSA wheels and the can not be lighteded or narrowed. On the official BSA wheels there is a mold nest to the tread that can not be altered. Thus, sanded down to change the dimension.

I do not have a lathe and my drill press is suspect as far as run-out. Thus, a buy wheels that are trued perfectly round. The stock wheels can be out of round. Furthermore, the axle hole sould be polished and the hub beveled.

The book a linked to about goes thru all this. I’d give you mine but I already promised to pass it on to a co-worker.

-- It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe. - Muhammad Ali

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lysdexic

4785 posts in 1247 days


#11 posted 978 days ago

IMO, you must polish and de-burr the axles.

-- It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe. - Muhammad Ali

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lysdexic

4785 posts in 1247 days


#12 posted 978 days ago

The gist of rail riding: Even if you get your car tracking perfectly you will not know or can you control the condition of the track. Rail riding is a technique of CONTROLLED misalignment to anticipate some drag but minimize it. It is not far off from perfect alignment.

-- It isn't the mountains ahead to climb that wear you out; it's the pebble in your shoe. - Muhammad Ali

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PinwoodDerbyDen

1 post in 978 days


#13 posted 978 days ago

Check out the PinewoodDerbyDen.Com web site, we have a lot of tips & links and are here to help.

View JSilverman's profile

JSilverman

87 posts in 1238 days


#14 posted 978 days ago

In our pack you must use the wheels that come in the official kit (which we distribute to all the boys). Axels can be polished and graphite used; both of those seem to help. But no modifications can be done to the plastic wheels. As I said earlier different packs have different rules but our district wide races use the same restrictions as our pack

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Dark_Lightning

1688 posts in 1733 days


#15 posted 975 days ago

http://www.derbytalk.com/

Lots of good stuff, covering everything from fast to paint to weird. Ethics of helping, etc., is also covered.

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