Cub Scouts Pinewood Derby 2012 thread

[mikester]

We have one of these about every year so I will be the guilty one and start this year's thread.

Our Cub Scout Pack's derby is next Saturday. I have run it the last couple of years and this year instituted a Dads/Siblings class. Same rules as the rest of the Cubs this year but I may go 'unlimited' next year for that race. Differentiating makes check in a little challenging as you have to keep the different cars apart.

Our rules are pretty basic. no more than 5.0 oz, use what is in the kit. Meet the dimension requirements. 4 flat on the track, profile of the wheels must not be modified but light polishing is allowed. If you want to go to the district race you have to use groves for the axles provided in the block. If you do not it is okay to drill new axle holes. In the event that you win and you have drilled axles guides then the 2nd place car goes to the district (assuming it is legal).

That drilled axle thing personally I think is a bit of 'luck' because our fastest car last year was standard. The closest competitor was drilled. Then next was standard. We only have a few folks who choose to do that. I did not do it this year to my car. We built two for my son which we are finishing up tonight and tomorrow I hope. I built one for myself and one for my 4 year old to race with.

We use tungsten weights toward the back end of the car but trying to balance the car just forward of the rear wheel. I do polish the wheels with graphite and debur and polish the axles. Also if they need straightening I do that. Get it to 5.1oz and then back it off a bit...

I let the boy do as much of the work as possible. He uses my scroll saw pretty good - next year he'll be able to do most of the work himself I think. He's approaching the ability to use the dremel tool too but I'm a little wary of that one (all supervised of course). He's not too good at the finishing part. Again, I direct and help there but that tends to cause a little frustration. So I usually back off a bit. Pinewood gets the worst of me sometimes...

Here is this year's entry for me. Pictures of his are coming too as we finish them up.



My wheels will go on there tonight.

[ckelly78z]

Make sure on the wheel nails that you grind back the nail heads slightly so only the very center of the head is actually touching the wheel. I put the sharp end of the nail in a drill chuck and sanded lightly with emory paper, and then spin the nail inside the wheel after hitting it heavily with powdered graphite (takes the burrs off and lubricates).

Weight placed at the front of the car will get it off the line quickly, but weight in the rear of the car will make it faster at the bottom of the track......not sure which actually gets there first, but my sons car passed every car there in the last 5'-10'.

I told him that he was responsible for the body and paint, while I showed him some tricks for the weight and wheels.

[mikester]

Also, I always build a car myself to keep my hands off my son's car. It usually works, this year he asked me to help him a little more and I obliged. I'm not a super competitive guy and I don't even really care much about going the fastest. I like to make a good looking car and always strive for speed but I have never been the fastest car. We did a track tuning night on Friday, we have a pretty long aluminum track. It's extruded to key together in lanes. Since I have taken over the Pinewood mantle for the two packs (and likely the district this year) I decided this year we need to realign the track as some of the lanes appeared to be slipping and the joints between track panels weren't lining up cleanly. Me and a few other dads spent friday night on the track. Of course we brought a few cars from last year and this year (one of the benefits of volunteering for track duty is testing your car). My son's car from last year was a little slower than we expected but this years car was definitely faster. Since Friday we have done a little more to it as well so the expectation is that it will be faster. I do make the nail heads a little cone shaped but not too much as I believe in taking off as little metal as possible. If you do too much the wheels tend to wobble. I do end up with a low ridge around where the head and the nail meet. I've also seen guys file a groove or depression in the nail to reduce the friction area. This is actually a little against our rules but we don't remove an axle to check for it.

Our track record was unofficially set on Friday at 3.089 seconds. Our track is about 40ft.

[red-beard]

BTW, it's 2013

[VaSteve]

For weights, what are you all using? I bought some lead fishing weights and thought I would just melt them with a propane torch. It didn't go so well. They just don't melt nicely. I remember doing it as a kid and it just poured in like those videos of a steel mill. WTH?

[red-beard]

I don't think they're lead anymore. Wheel weights are lead. Or, you could use solder from home depot.

[VaSteve]

Ah. Didn't think of that. Many wheel weights aren't lead any more either.

[mikester]

Yes, 2013...

Anyway. Lead = Bad. First of all it is kind of toxic and when melted down is bad. I did the same thing when I was younger though so how bad can it be really? I mean I turned out great? How much better could I have turned out?

I'm not sure if the stuff in today's fishing weights is actually lead. I used fishing weights last year and I'm sure they are fine. I like the ones that pinch onto the line. They come in a variety of sizes so if you are getting to the right weight you have a lot to choose from to get there.

This year though I sprung for some tungsten weights; tungsten is more dense than lead and not toxic. They come in nice shapes that you can easily place in the car and since the weights are small they can be placed strategically using a drill instead of hollowing out a huge chunk of the car.

I hope my wife doesn't audit my pinewood spending...

[gsxrken]

We had our last Pinewood last year, and I already lament that its over for my sons and I. It's imperative that you let them do the work, ask them for their ideas, let them use your tools, and spend time with them. It was one of the few projects that father and son can work on; so often on the cars or the house projects, it's too critical that the cut doesn't overrun the mark, that the screwdriver doesn't slip and gouge something, or that this or that has to just-so. Or so it seems at the time. I saved their cars and they are priceless. Enjoy it while you can.

[VaSteve]

I have you beat I'm spending. I bought a bandsaw last year. I cut last years car and this years car on it. That's it. Plus, the blade twists, I néed to find the owners manual.

[Cajundaddy]

Pinewood Derby was fun when I was a kid. My dad was an aerospace engineer and our cars were always competitive. One time All City winner.

The winning cars were aerodynamic with weight low and just forward of the rear axle. Nose and tail of the car were beveled up so it would not drag where the inclined track section met the level track section. Wheels & axles were carefully chosen and de-burred, nail axles were carefully polished. My Dad made a jig so when we mounted the axle slots to the car body they would be absolutely true. Then when we mounted the wheels/nail axles they were re-checked for true. Graphite powder was added to the axles prior to each run. Yea we might have been a wee bit competitive.

[mikester]

I'm lucky at the moment, my oldest is only in his second year in scouts. My youngest hasn't started yet but LOVES it already. I built cars with both of them this year and last. The 4 year old's doesn't get much real attention to detail but he loves it none-the less. My oldest wanted his car to be pretty sweet this year. Last year's - I thought - was great. He did a Finn McMissle car and it looks pretty good to me. I helped him lay out the design on the block and we cut it out together on the scroll saw. He sanded it and when he was ready to paint I handed him the brush. We did some paper cutouts for the details like his face and windows and head lights and what not. Glues those on and then he put ALL the numbers on it. We graphited it up and were ready to race. It was middle of the pack as far a speed was concerned.

He didn't have the patience to pay attention to the details required to make it 'fast' but other dads did it for their kids or maybe their kids did have the patience. How am I to know for certain. So this year I decided I would help him with those details more but leave as much of the car up to him to do and let him know that I'd be happy to help him at his request but it was his car.

There isn't much way to prevent over-zealous Dad's (including myself) from working on their kids cars but this year he was able to pay more attention to the details and was willing to work a little harder and said he did want to be faster and wanted me to push him. I don't really want to push him - I just want him to enjoy it. Last year he was really upset afterwards and our winner was most certainly a Dad-built car. Now, my oldest's car probably looks like a 'Dad-built' car. It isn't, I instructed him and I helped him but I didn't build it. We did. Tomorrow or Wednesday we'll need to get those wheels on though...

[Hydrocket]

This was fun when I was a young lad. However, it was quite obvious that MANY of the cars were not made by the kids, and were made by their fathers.

I suspect this still occurs....

[eskimo]

This was our first year doing this.. my son is 9 and I just stood back and watched.
The car was very consistent... although not fast. Next year...

[Cajundaddy]

The way we did these builds was a team effort utilizing the strengths of each team member.

Year 1- I was in charge of body and paint (with dad supervision and guidance). Dad was in charge of wheel and axle prep and mounting while I supervised. The car looked good and was very fast.

Year 2- I did all body and paint solo, prep and polished wheels/axles (with supervision). Dad carefully mounted the wheels and fine tuned the lead weight. Car was less attractive and fast- All-City winner.

Year 3- I was less interested in this game now. Built the car quickly, entirely on my own. It was butt-ugly and not as quick but still top 5 in the pack I think. My brothers were now getting the dad engineering input and their cars looked great and were very fast.

[Icemaster]

Mind if I plagiarize your design?

[HardDrive]

I recall my dad taking one of my mothers large metal kitchen spoons, pouring in some lead shot, and melting it with a torch. He then poured it into a couple holes he had bored into the bottom of my car. Worked like a champ. Mom didn't appreciate losing the spoon.

[mikester]

Originally Posted by Icemaster

Mind if I plagiarize your design?

My design? Sure - have fun. If you want I'll make some drawings with my contour tool.

[VaSteve]

I looked, the weights contain lead. I guess they are not all lead. What a pain.

At our pack, we watch this movie called "Down and Derby" about a group of guys and their sons competing in the pinewood derby. The kids like it, but it has so many plot holes, it's rediculous. I can't bring it up though so as not to ruin the fun. Anyone else seen it?

[mikester]

One of the Troops that runs out of the same place as our Pack hosts a showing the night before our Derby.

I own a copy. I can't tell you how hard it is not to go out and buy my own two or three lane track (not that I don't have access to the track we use since I'm basically the custodian of the track as it stands now).