Pinewood Derby Time

[HVAC Cruiser]

OK, so its Pinewood Derby Time with the boy scouts The last time I helped make one ( actually made them less painting don't tell) was actually for my daughter then for one of her friends in the girl scouts.her mother was my secretary.

Anyway anyone know any tricks aside from polishing and using graphite on the axles and polishing up the wheels?

added note: at what age do you think its right to start teaching your 7yo boy how to use power tools such as a detail sander?

 

[tx1961whaler]

Re: Pinewood Derby Time

Pinewood Derby Tips
1. The boys and adult should make the car together as a project! It is not the intent that the parent show the Scout the garage door then walk away; nor is it the intent that the boy play video games while the adult cuts and sands. Parents should shape with the power tools and then direct the rest of the action while showing the boy each step in building a car.
2. Have fun! After all, this is what it is all about.
3. Know the rules. Being disqualified can be very embarrassing.
4. Safety first. Let's not lose any fingers.

Design Tips
1. Have your son draw a design on paper then cut it out and use it
as a template. I use the paper with the little squares on it to make it
easier for him. Draw a side and top view on the paper by tracing around the block of wood.
2. Keep the car a full seven inches. It has to do with the physics of velocity and length of travel of the weights.
3. Use the full 2 3/4 inches (outside wheel to outside wheel) that the rules give you. This will allow the
wheels to travel farther before hitting the center strip.
4. Leave a lot of wood in the back to put in the weights.
5. Use the groove closest to the end of the block of wood as the rear axle.
6. Do not make the front of the car pointed. It is hard to set up against the starting dowels.
7. Use your imagination. Be creative. Shape has the least to do with winning. A beaver driving a log or even a pickup truck is more interesting than a wedge and will be just as fast. The aerodynamics of a small block of wood doesn't mean much in thirty feet.
Lubrication
1. Use graphite only. Oil damages the paint and collects dust. I'm
told that the graphite works better than the new white Teflon.
2. Break in the wheels by spinning them with lots of graphite.
3. Right before check-in, fill the wheels wells with graphite and cover
with stickers like a hub cap. You can paint the 1 inch stickers in a
contrasting color. It looks great!
4. Put a small drop of white glue where the axle goes into the car body and put powdered graphite on it there. That causes less friction if the wheel should rub against the car body.
5. Other than the good polishing of the axles, dump the axles and wheels in a ziplock bag with some
graphite and shake them for a few days prior to the race. That way the wheel and the axles are as slick as can be.
It's Time To Go Straight!
1. Put the axle in at a downward (5-10 degrees) angle. This provides two benefits. The first is the only the inside edge of the wheel is in contact with the track. This seems to make the car go straighter with less wobble. The second benefit is that the wheel rides to the outside of the axle and doesn't come in contact with the body. This tip is for experts only. First timers have trouble getting this right.
2. Axles must be in straight front to back. That is square to the body. True the axles, don't trust the slots! If you have one, use a drill press to ensure all axles are straight. One of the front and two of the back should be measured to be the same height.
3. After pressing in the axles, test the car for crooked wheels...roll it on the floor. If the wheels are on
straight, the car should roll 8-10 feet in a fairly straight line. Should the car turn left or right, you need to tinker with the axle placement without removing them from the car body, until it rolls straight.
4. Do not put the axles in at the top of the groove. Put them in at the middle. This lifts the car of the track a bit more and reduces the chance of rubbing on the center strip.
5. Glue the axles in place. Nothing is worse than having the wheel fall off as you cross the finish line.
6. Once you match a wheel and axle together with graphite, keep them together. They wear into each other as a matched set.
Weigh In
1. Get the weight as close to the 5 ounce limit as possible.
Add the last little bit of weight with lead tape from the golf
shop. This can be trimmed with scissors at the last
minute. Remember, the official scale may not weigh the
same as yours.
2. Everyone has an opinion on where to put the weight.
My belief is that the weight needs to be predominantly in
the rear so that gravity can act upon the weight further up
the incline and for a longer period of time A car with more
weight to the rear generally grabs more speed down the slope. Many suggest having the center of gravity at 1 to 1-1/2 inches in front of the rear wheels. But be careful not to put too much in the rear or you'll pop a wheelie.
3. What kind of weight? I think the melted lead is dangerous and unnecessary. Tubular weights can be sunk in the sides; flat weights, like those sold at hobby & council stores can be attached to the car bottom if it is carved in a bit. Incremental weights ( with pre-marked grooves) are easier to snap off
into the size you need. Some folks just use BB's, nuts & bolts, etc., but these must be glued so that they can not move. No movable weights or mercury are allowed.
4. I like the round weights found at the hobby shops and craft stores. This allows us to stick the weights out the back of the car. We paint them and tell everyone that they are jet engines or tail pipes. What they really do is allow us to get the weights as far back as possible.
4. Keep the weight low on the car and in the center (Left/Right of the car). Put the weight just in front or behind the rear wheels for less wheel chatter.

 

[Tubingluvr]

Re: Pinewood Derby Time

what are the axles made of?
My last derby car was years ago when my 22 yr old son was young.
At that time the axles were steel and I worked for a heavy metal stamping factory that made front bumpers for ford trucks and vans.
I had the axles chrome plated in our plating dept and waxed the heck out of them with carnuba wax.

 

[puddle jumper]

Re: Pinewood Derby Time

Silicone lube spray on the axles and wheel alignment wins every time.Plus make sure the car has enough road clearance in case the track has a high spot and rubs on the under side of the car.

The first year my son an I did it we all got our box of parts and block of wood. Well every one got a pine wood ours was spruce. Don,t know why but it was. So my son and I built the car with out a scale. When we entered the race our car was two heavy. So thinking we cheated they drilled our car looking for added weight but could not find any. The look of all of the parent,s I could have just died.

 

[tashasdaddy]

Re: Pinewood Derby Time

my son was with me all the time, he learned at a very early age. at 14 he could operate, a backhoe better than me. he also lead a team of 5 workers as he operated the backhoe. he is now a 33 y/o construction engineer.

 

[HVAC Cruiser]

Re: Pinewood Derby Time

what are the axles made of?
My last derby car was years ago when my 22 yr old son was young.
At that time the axles were steel and I worked for a heavy metal stamping factory that made front bumpers for ford trucks and vans.
I had the axles chrome plated in our plating dept and waxed the heck out of them with carnuba wax.

Hi Tubingluvr- the axles are little steel nails, plating them must have helped a lot, unfortunately I don't have those kind of resources

Thanks tx1961whaler, That's a lot of great info.
You either were reading my mind or between the lines with your 1st tip, I agree with you wholeheartedly . I actually edited and rewrote my initial post, that was my reason for the power tool question. By boy actually said something that upset me a little. He was almost looking to me to Just Build the entire car for him, which I will not do . I believe this project helps teach working for and toward something , not just having it handed to him.

Here is what we have done so far
1) I did re-drill the axle slots on my drill press to square and true them
2)He picked out the design off the internet, printed then cut it out and traced the template on the block of wood
3) I started making the initial shape for him with my belt sander intentionally left it a little rough , showed him how to smooth the surface by had using pieces of sand paper.

questions:
Following the template and I just looked at a bunch that he printed out the axle closet to the end is the front, should I modify the shape enough to flip it around, its almost symmetrical its an easy fix.

I will keep you posted on the progress and post some picks

 

[fishrdan]

Re: Pinewood Derby Time

The best things I picked up that my son and I did on his car were.

- True the axles on a drill press, chuck up an axle and spin it in the drill press while holding a screw driver on the side of the axle, it should feel perfectly smooth, not hopping. If it hops, you need to tweek the axle a bit so it runs true.

- True the axle/nail heads with a fine file to take off any high spots off the head.

- Polish the axles on a drill press, WD40 and progressively higher grit sand paper ending at 2000 grit. Once it's smooth with 2000 grit, hit it with some polishing compound and denim jean material.

- Chuck up a wheel in a "wheel jig" and sand the tread of the perfectly flat and true with progressively finer sand paper and WD40 ending at 2000 grit. You will need a square block of wood to rest the sand paper on so you are sanding the wheel against the block of wood, while the wheel is in the drill press.

- Polish the wheel bores with polishing compound. Chuck up a pipe cleaner in the drill press, slather it with polishing compound, push wheel onto pipe cleaner, turn on drill press and run wheel up-down the pipe cleaner reapplying polishing compound a few times.

- As tx posted, 1 of the front wheels should be "lifted" and the car should be balanced so it rides on 3 wheels. We set one of the front wheels 1/8" higher and it would ride without that wheel touching most of the time.

- Move the axle locations so the wheels are even with the front and back of the car. We clamped a block onto the drill press so all axle holes were at the same heigth,,, well except 1 of the front wheels.

- For weights, drill a couple holes in a board with a Forstner drill bit, grab a couple 1oz and 1/2 oz fishing sinkers, drive a screw driver into the sinkers line hole (for a handle) and then melt the lead into the holes. This makes perfect 1oz and 1/2 oz weights, I think we used 1" and 3/4" Forstner bits. Fine tuning the car's weight can be done with regular sinkers.

- Weight placement was between 2/3 and 3/4 back, right in front of the rear axle. Use the Forstner bit to drill holes for the lead slugs you just made, the slugs will be a touch loose as the slugs shrink when they cool, epoxy them into the body.

- Fine tuning weight can be done with a electronic scale, I picked one up from Harbor Freight for $20 and he dialed the car into just shy of 5 oz, it was like 4.99999999999oz The fine tuning weights should be siliconed into the body,,, just in case the "official" scale is slightly different.

-Gap the wheels, we used a credit card for wheel to body clearance.

I would say we put as much time into the axles/wheels as the rest of the car. I would show him how to do 1, then he would do the other 3. He pretty much did the entire body on his own (under close supervision) as he was using some power tools, mostly hand tools though.

In our pack, the last chance you have to do anything to the car is at weigh-in, so graphite your wheels 1 last time before weight in. Once you finally weigh in, they take the car and store it until race day.

I think it took us 10-15 hours to make the car, but it was worth it. His first year he won 1st place! The pack leader build a "hotrod" car, just for messing around, and after the races were finished the pack leader wanted to race my son's car... I think he raced my sons car 8-10 times, but he never won.

I got the feeling they thought we "cheated", but I knew he did 90% of the work on the car. I guess it's his fault his dad is a woodworking/mechanical nut...

 

[fishrdan]

Re: Pinewood Derby Time

added note: at what age do you think its right to start teaching your 7yo boy how to use power tools such as a detail sander?

My son was 7 when we built the car I posted about and he was using the drill press and vertical belt sander, everything else was hand tools, saws, sanding blocks, etc. Close supervision and specific instructions on how to use the tool is a must. Let them know this is not a toy and not to be used unless I am there and know you are using the tool. Let them know what can happen if the don't use the tool right, drill press and loose clothing will wrap you up, shove a stick into the belt sander and ask them if they see how quickly the stick disappeared,,, that could be your finger , etc. My son used the tools well and if I saw him straying (not paying attention, playing) I would quickly correct him.

 

[4JawChuck]

Re: Pinewood Derby Time

We had a mixed experience with Pine Wood Derby racing.

I went out and bought a 0.1 gram accurate scale so we could be on the money and we built two cars and one truck. The boys did all the building and assy and painting. We spent a lot of time searching the internet for tricks and tips and we had a good time learning, building and playing with them in the basement. We built a test track and used a stop watch to time them to find out what worked and what didn't. We even melted and poured fishing lure lead into the blocks to get the weight low, they thought that was the coolest. Make sure you do this before painting!

If I could offer any tricks I would say go out and buy a couple more kits so you have an assortment of wheels and blocks with precut grooves to choose from before you go crazy cutting and shaping, some of the kits are substandard and either the grooves aren't straight or the wheels are malformed (the kits were only $9). Most of the speed gains are in axle prep and alignment, the "nails" they give you in the kit have a raised edge on the inside...this needs to be filed off and then the axle seat polished and nailhead faced and polished to ensure its perpendicular to the seat. Prelube the axles with moly powder not graphite, its faster...a q-tip is the best way to lube the wheels with moly powder while they are off.

Last thing to consider is the launching peg...anyone rounding the bottom of the car at the front is cheating according to the rules as it launches the car ahead of the others. Don't make a pointy front end, aerodynamics have little effect on the cars...trucks are a little different. Don't camber the wheels too much and make sure it rolls perfectly straight without wheels wobbling, don't glue the wheels on...drilled holes is the best location method. The slots have too much play after the wheels go on and off a few times so we flipped the blocks and drilled holes for the wheels instead. If you use the slots a hot glue gun is great for holding the axles located, make sure you disassemble and lube the wheels before the race and don't let them play with them before the race...smash up derby and throwing them can ruin the alignment (thats why we built a couple cars). Whether to build a three wheel as opposed to four wheel car depends on your track, if it isn't perfect a four wheel car is better for stability and tracking.

On race day the car that won was so much faster than the all the others that I went and weighed it while it was on the stand after the win (I had my own scale tyvm!), it literally left everyone else in the dust off the peg during every race no matter which lane it was in (there is a fast lane btw). A leader quickly approached me and said there was no weighing of cars after the event? Yea right...it was 50 grams heavier than all the others according to my scale. The problem is no one wants to disqualify a kids car if its a "cheater". Overweight is one thing but blatant is another...as you can guess...it was one of the leaders sons car that won.

Might I suggest you get involved with the pre-inspection and ensure a post race weigh in to eliminate cheating. We left with a best looking car and best looking truck award. I was more than a little disappointed that they allowed so much cheating in the car building, one kids car had a professional paint job done in a body shop! WTH? Another had carbide axles with metal heads, yet another had thinned wheels...its kids playing with adults interfering...don't expect fair.

If I was going to do it again I would concentrate on the "show" aspect of the building and leave the cheaters to decide the "fast car", the kids don't care and having a nice looking toy in the end is what its all about. BTW the most popular vehicles were the "theme" cars and trucks, one boys Batmobile was so authentic it was amazing...Dad built the entire thing in a wood shop obviously...not sure what Dad was thinking.

Here's my oldest boys truck, he did all the work! BTW He donated the truck to the local FedEx depot at the airport and they presented him with a nice fat donation check for his pack!

 

[Bob_VT]

Re: Pinewood Derby Time

Pinewood Derby has been here before..... read the old posts on what worked too

http://forums.iboats.com/showthread.php?t=31950&highlight=pinewood

http://forums.iboats.com/showthread.php?t=26210&highlight=pinewood

 

[tx1961whaler]

Re: Pinewood Derby Time

what are the axles made of?
My last derby car was years ago when my 22 yr old son was young.
At that time the axles were steel and I worked for a heavy metal stamping factory that made front bumpers for ford trucks and vans.
I had the axles chrome plated in our plating dept and waxed the heck out of them with carnuba wax.

Just a couple of points, plating is not allowed and only dry lube can be used.

 

[a70eliminator]

Re: Pinewood Derby Time

Ok, here's a tip for you from the fastest car in our pack, the winning car did not sit level on all fours, it teeter tottered on the front left and rear right, I know it sounds crazy but I attribute it to less rotating mass and resistance being only two wheels were touching? All I know is the car was my little brothers car, made all by himself (dad was truck driver and didn't much time) ugly and square but a winning car.

 

[HVAC Cruiser]

Re: Pinewood Derby Time

Thanks to everyone for their input, Worked a real long day yesterday so Liam and I didn't get a chance to work on it last night (dad was real tired and hurting). We are going to pick up on it tonight.

After reading all the tips it seems it comes down to 2 things reduction of rolling resistance, by working the axles and wheels and weight. I have a digital postal scale so we should be able to get it real close to the 5oz

I have been arguing with myself over how much to help, especially now, after reading some of the 2005 & 06 posts on the link Bob put up.
I want this to be his achievement and a learning experience for him. Here is what I've decided, I have already formed the shape for him and left it a little rough, he is going to do all the sanding and painting with my supervision. I will have him assist with the axle & wheel polishing and explain why it is important, I have burnishing tools that I will assist him with using for the final axle polish.

He is a cub scout, Friday is pack night and they are all bringing in their cars and a kits where boy scouts help the younger ones, I am getting him another car for that night we will bring this one to check it on their scale.

Wifey just told me something I don't like though, weigh-in is on the 12th and they then keep the cars till race night on the 15th. My thought is anything can happen to it in those 3 days I'm thinking of packing it in foam

 

[jevery]

Re: Pinewood Derby Time

We just finished ours. Pretty much filled it with weights because we removed so much material, and still had to put one weight under the arch, but got weight up to 4.95. My son's really excited.

 

[tx1961whaler]

Re: Pinewood Derby Time

I run the event for our pack. I make it pretty clear that this is for the boys to do, learn something and have fun doing the event. The way I get around the dad's trying to relive their childhood is to have a Dad Car/Outlaw race as part of the event, after the scout's races. Those cars can be whatever they want to be. Any car grossly out of spec/overweight runs in this, but I have a drill available for the legitimate cars that happen to be a little overweight to get rid of some weight and get the cars checked in for the real race.

 

[HVAC Cruiser]

Re: Pinewood Derby Time

That's a cool looking car jevery Lots of luck to your son

Well we did some work on it last night here is my little guy sanding his heart out on her.
P.S Please no comments on me not finishing the oak work between my dinning room and kitchen, I get enough of that from wifey

I did make one mistake so far, I had cut the shape for him prior to posting here . He had lined up & traced the template exactly as it was, the axle closest to the end of the block was in front on this template .

I did buy him another block of wood to do it over and cut the rough shape with him because I don't know it the rules allow you to fill the axle slots and drill new.
I believe they just follow the standard BSA rule book.

One thing I did notice with the wood blocks is that the one from the BSA store is a lot heavier than the one from the craft store. Both have the official BSA logo on them. The one from the craft store is by Revell if that means anything.

What I am thinking though is that the lighter one will allow us to put more weight in the rear of the car
Any thoughts?

 

[HVAC Cruiser]

Re: Pinewood Derby Time

I don't mean to go off on a tare BUT

So my son and I went to pack night for the cub scouts last night, normally my wife takes him I am usually off on a call or doing billing or something. This was a real eye opener

I have to say I'm a little upset and disappointing. The leaders were 1st giving a class to the boys on the use of tools, one of the highlights during the lesson the one giving the lesson showed how you remove a SCREW with the claw of a HAMMER , said a "C" clamp was a vise grip then another one jokingly made believe they were putting a spring clamp on their NOSE!! and this is not even the half of it
I know their intentions initially were good BUT OMG OSHA would just love these folks
I also found out that they really aren't taking the derby serious, winning or loosing is going to be judged by eye, no trip meters of any sorts.
There will be a weigh-in, have to adhere to the rules and regulations as far as the cars go but that is where it ends.

Not that I'm the greatest thing since scrambled eggs BUT In light of what I witnessed last night I think its time for daddy to get a lot more involved see about becoming and assistant leader or something.
Here is my question to all you scout leaders and such out there, how should I handle this?

 

[HVAC Cruiser]

Re: Pinewood Derby Time

Thanks for all your tips

Ran the Derby Last night, Liams car won the two races that he ran. Each time the car hit foam the stop at the end of the track and bounced backwards halfway back up the track .
They did a Nobody Wins Nobody looses routine,EVERYBODY WINS . The cars only ran 2 races each, it wasn't heats down to elimination rounds and final heats. At the end they only picked 1 car they said was the fastest based on time.
My son was happy he won his races but I'm a little confused, when I used to do this with my step-daughter for girl scouts it was heat after heat down to 1st, 2nd, and 3rd.

I kinda feel that they undid lessons I have been trying to teach him. Initially he had said, he was going to win. With that comment I have been stressing that everybody looses sometimes. You can't win everything in life, sometimes you loose, people loose all the time. I also told him he probably wouldn't win BUT As long as you always do the best you can, try your hardest and learn from experiences that's what matters most.

Maybe I am over thinking it or just being a jerk but I think the everyone wins bit is wrong, if little Johnny or Liam in this case looses then so be it. It can be turned into a try harder for next time.
I feel its better to loose than have wins just handed to them for I think that will just make them poor sportsman & sore looses in the future. I don't want him thinking things will be just handed to him.

Any thoughts?

 

[tx1961whaler]

Re: Pinewood Derby Time

We have winners for the races in our pack. It's based on averaging the results of 3 heats (car is raced once in each of the 3 lanes). All races are computer controlled and timed. All of the kids go home with something, however. Little trophies for 1,2,3; ribbons for the rest.
For the slowest car, we all circle around the child and parent screaming "LOSER! LOSER!", paint them red and expel them immediately from the pack. Can't have those types around. ( PLEASE FORGIVE THE HUMOR --JUST JOKING !!!!)
There are plenty of opportunities to volunteer and get involved. Start out by volunteering to lead different activities, then go for a higher position when everyone gets to know you.
If your son was happy with the way the night went, then mission accomplished. He's a good sport. I wouldn't over think the pinewood derby thing; I don't personally think that any great life lessons are learned here, other than "scroll saws can cut your finger off" and "hand sanding is a pain"

 

[12vMan]

Re: Pinewood Derby Time

LOSER, LOSER! That's funny!

My son has run this for 3 years, and all 3 cars have been 1st place winners. He designs, I do the initial cutting on the band saw, he sands & paints.
When we install the axles & wheels (our axles have always been small shoulder screws) I don't bother truing the holes on the drill press. Instead I just put the car on the treadmill, sand the nibs off the wheels and align it with my finger on the front until I can crank the treadmill up to 10 mph without the car wavering either way. We always use graphite.
This has worked almost too good. I let a few of the secrets out each year, and the cars are never a work of art, but my son's cars are always so much faster it almost seems unfair
When we get to the event my son keeps his car safe in a padded shoe box and is serious about not letting any of the kids touch it until after the races so it doesn't lose alignment or get damaged.
The Scoutmaster said he will present my son with a special trophy this year if he wins again