Відео

Nice work - congratulations!

Thank you for the kind words. I'm glad you found the video helpful. Good luck helping your team of grandsons - sounds fun!

Keeping the rear axle close to the rear of the car is best. This keeps the balance point as far as possible to the rear, which means the car starts off with as much potential energy as possible.

I don't have as much experience with Super Glue as epoxy, but Super Glue should work, especially medium thick Super Glue like www.amazon.com/FastCap-80113-Professional-Medium-Adhesive/dp/B000WUI0PA, which is designed for woodworking.

I made two videos that are similar. I posted answers to your questions with the other video: ua-cam.com/video/fOamVOSvimk/v-deo.html

These are all very good questions. I'll try to take them one-by-one. 1. AXLE POSITION: If you must keep 4.5 inches between axles, put the excess wood in the car's front. Do not shorten the car. Another option is to use the axle slots provided with the block of wood. If you do, be sure to drill them out as shown in the video (12:11) and glue the nails in their final position. 2. GLUE HOLES: When you place the nails into the holes, you should see the nails at the bottom of the glue holes. When the nails are in their final positions, drop a little glue down the nail hole. 3. WEIGHT PLACEMENT: The balance point -- NOT the weights -- should be 3/4" to 1" in front of the rear axle. The weights will usually be located somewhere behind or over the rear axle. The precise weight location is not critical. They don't need to be stacked on top of the balance point. It is the balance point location (not weight location) that is important. The video's final photo (14:50) shows where I put the weights on my demo car. They were attached with epoxy. 4. BOTTOM CLEARANCE: I do not recommend attaching weights to the bottom of the car. Not only do they get in the way, they also can fall off. 5. BALANCE POINT: There is no trick here - just balance the car on any vertical straight edge placed across the bottom of the car to determine the balance location. If you don't have a ruler, a thick piece of cardboard (cut from an Amazon box, for example) would probably work. Hope this helps. Feel free to post any follow-up questions. Good luck!

@@EngWorkshop Thank you, John. I feel like you are my lifeline in this venture. I am still a bit confused on the balance point, In order to find the balance point I should have the car with it's wheels and axles on but no weight? Once I find the balance point I make sure the weight goes behind and up to that balance point? Sorry, I am such a novice on these things, I appreciate your time and help.

To adjust the balance point, put the wheels and axles on loosely and stick the weights with tape somewhere over the rear axle. It's hard to see in the video (5:46), but the axles are barely in the holes for this step, and the tape is hidden underneath the weights. Move the car forward or backward over a straight edge until it balances - this is the balance point. If the balance point is not where you want it (3/4" to 1" in front of the rear axle), move the weights toward the front or rear of the car until the car balances at the desired point. This will take a little trial-and-error.

@@EngWorkshop Hi John, I've been waiting for weights and things to arrive from Amazon I loosely put the car together as you mentioned (wheels and axles barely on) with weights and the balance point is 1" in front of the rear axle and my left front tire is up (yay). I still have to paint, glue axles but as it stands right now we are weighing 4.9. I wish I could send you a picture. I had to cut the car out with a coping saw - it was very rough going. The wood was gouged in a few spots on top so I used pine derby putty, let it dry and sanded it. I may have to do it again in one spot. Once that cures and is sanded we'll be ready to paint. I just can't thank you enough. God bless you!

Sounds like you are on the right track (pun intended)! Glad to help. Good luck!

The drill bit size is #44. This is a machinist size and is slightly smaller than a common 3/32" bit. You can find #44 bits on Amazon or any online Pinewood Derby supply store.

We used 2-part, 5-minute epoxy. Others in our pack have used hot glue, but the bond with hot glue is weaker, and the weights occasionally fell off during the race.

In the comments below the video, I added links to the supplies and special tools. Hope it helps!

Some packs actually have an award for the slowest car. Our pack called it the "Best Gas Mileage" award. I think it would be a much harder task to design a car to win such an award.

We have never baked our cars. Baking makes the wood lighter so that it might be easier to achieve the correct balance point when adding weights. But with a proper body shape that is not too heavy in the front, there should be no trouble achieving the optimum balance point without baking. I would worry that baking could crack or warp the wood, although I have never tried it.

Indeed, the car in this video was made by me for demonstration purposes. As a former Cub Scout leader, I recognize that Scouts have an extremely wide range of abilities, even at the same age. A few Scouts can do the build steps by themselves, but most seek help from a parent. I made the video as a resource for both DIY Scouts and helper parents in response to questions that I received from both groups.

Because the weight of the car presses down on the axle, the downward side of the axle presses on the inside bore of the tire. Having the ridges facing upward means the downward side of the axle is the smooth side, theoretically reducing friction. The improvement is probably small, but every little bit helps.

That is correct, but there is a caveat. If the car is balanced on a very thin ruler, then the car may never stop wobbling, even if it is on the balance point. We use a metal ruler that is about 1/16 inch thick so there is a flat (but narrow) edge on which the car can rest.

The axle ridges are not related to steering, so it's no problem if you don't have them. They just cause extra friction, so you're better off not having them. Instead, steering is accomplished by positioning one of the front axle holes higher than the others (10:04) and slightly bending the other front axle (8:51). The car's direction is changed by turning the bent axle slightly (10:44). This method is used in the video. The ridges have nothing to do with the bend, but you still need to make a mark on the axle head so you know which way the axle is bent, because the bend is so slight. Hope this helps.

I completely agree with your statement about the Pinewood Derby's importance as a collaborative activity between parent and child. We made the video in response to questions I fielded from parents and Scouts when I was a Den Leader. We hope the video will serve as a resource for parents and Scouts alike.

Assuming the car dimensions are the same, I think all the design considerations would be the same, except that you can have a little more total weight.

Congratulations! Well done!

If the axle slots must be used, it is a good idea to drill them out and glue in the nails, as shown near the end of our video. Otherwise, we have found it is easy for the slots to be damaged during axle installation, or the nails to fall out during the race. Much of the video's process could be adapted for your son's Pack. For example, the principles of weight distribution still hold. And if the axle slots are drilled out, you probably can use the same method of wheel alignment. Either way, thanks for watching and good luck!

I drilled new holes on the other side, then cut with a saw just enough to make it look like I used the slot, then filled them with putty. Just in case they got picky. After I cut the car body design the original slots were gone.

The design shown in the video is 3/8 inch in height.

While we are lucky to have a home workshop with a band saw and drill press, neither is a necessity. The car in the video was made with only the "basic" tools shown in the opening. But making the fastest car does require some tools, and the definition of "basic" may be relative, as you imply. Fortunately, the most important step requires no tools: planning the best weight distribution for a given car design. I'm sure you are far from "useless" in helping your child. Good luck and, above all, have fun!😀

UA-cam "Easy pinewood derby wins using science". Trust me.

I'm a father. I come from three generations of single mothers. I completely understand your anger and frustration. I also have never had anyone to show me how to do things like this. Then the pack leader shows up and says, "OK, everybody! Time to build a pinewood derby racecar!" like we're all supposed to just magically know how to it's done. It's incredibly frustrating and it makes you feel like such a loser.

It's basic in the sense of woodworking tools. Props to you for helping your kid in their pinewood derby.

Only an engineer would think this was basic...haha

Whether using a drill press or hand drill, you need to use a #44 drill bit, which is slightly larger than 5/64" and slightly smaller than 3/32". You can buy #44 drill bits from online Pinewood Derby supply stores or Amazon.

I meant 6 yo

Well done! Congratulations!

Well done and congratulations to your daughter! I wish I could have seen the car.

The differences in design are 1. instead of the left wheel raised, we had the right wheel raised. 2. Also we could not find the rectangular weights so we went with the cylindrical weights and superglued them together to create a rod like structure and placed them at the end. @@EngWorkshop

Thanks for sharing the photo. As you figured out, it doesn't matter which side has the raised wheel. I just had to pick a side for purposes of the video. And your cylindrical weights look better (less utilitarian) than the rectangular ones.

can you share the photo of your car?@@NP-ge6um

You're welcome, and congratulations!

Good job, and congratulations! As you probably discovered, weight position is still the most important factor even if you can't change the wheel positions. Wishing you continued improvement!

I have purchased weights from www.maximum-velocity.com, but they are also available on Amazon.

Well done! Congratulations!

We bought the drilling guide from www.pinewoodpro.com. Similar guides can be found at other Pinewood Derby supply sites, such as www.maximum-velocity.com and www.abc-pinewood-derby.com. If you use a drilling guide to lift one of the axle holes, you may find the hole is lifted by more than the 1/16" we recommend in the video. That is OK, but it might increase the risk of the car jumping off an uneven track. If you want to drill holes at exactly the positions shown in the video, you may have to experiment a little with index card shims placed between the drilling guide and wood block.

When I inserted footage showing the band saw and drill press, I probably should have made it clearer that this video's car was actually made using only the hand tools I showed at the beginning. Although helpful, a band saw and drill press are not required to make a winning car.

@@EngWorkshop You made that clear. I heard it clearly the first time I watched the video.

Thank you for the kind comment. As mentioned in the video's description, we made a second video showing a step-by-step example of how to implement these tips.

Thanks for the sympathies, but they're not necessary, actually. Making the sample car itself took less than a couple hours, which was insignificant compared to video production. Past cars of similar design and construction all won their races, so we're pretty sure the sample car would have done the same.

Fastest car was #512, second row, fourth car from the left. It was my car for our Pack's parent race one year. Over the years, I have participated in the parent race using cars of similar design and construction, so I'm not certain why one car would run faster than the others. I wonder if slight differences in track setup might be the cause.

This is true, in theory. We have seen some car designs that implement this principle. How much difference this makes is unclear. The spring-loaded starting pin found on most PWD tracks releases the cars much more quickly than they accelerate.

Thank you for the kind words. I don't like rambling videos either!

Were you given a reason why a thin car wouldn't work?

@@EngWorkshop no we were not given one. It were strongly advised to make it thicker. we ended up making it a little thicker and we won 2nd place out of the entire grade so it ended up working really well! great video it was awesome for people with no wood experience!

You're welcome!

I think the proper gap between the wheel and body is important. As shown in section 8 (wheel installation), the gap should be 1/32 inch. The video shows how to make a spacer to help achieve the proper gap.