Pinewood Derby 2022

[LCHIEN]

I have two grandsons and both are entering.

Polishing wheel axles.

unpolished typical axle from the kit on the left, after deburring and polishing through 5 grits on the right

[LCHIEN]

Precision tilt jig for cambering PWD wheels 2.5°

https://www.sawdustzone.org/forum/di...ision-tilt-jig

[LCHIEN]

progress

[Jim Frye]

Ah, the memories. I remember polishing the axles and then burnishing the wheels and axles with graphite using a drill with the rubber disk sander minus the sand paper to spin the wheels. Didn't know anything about the camber back then and the axles were nails. Back then the CW was nose weight bias. I was the age of your grandsons then. The competition was well established 65 years ago and it's still going.

[dbhost]

Love the progress!

[LCHIEN]

Younger Grandson's car. Something he built of Lego he wanted to transfer the design to the car.
Made a bunch of scaled precision LEGO shaped pieces





Some on-the-fly changes were made.



Get up close to the allowed 5 Oz. three half oz fishing weights, a 1/4 oz weight and a #6 x 1/2" screw. (0.03 oz)





Some wheel lube is still needed and testing. Got out the old test track and a previous car for comparison.

[LCHIEN]

Had to slot some nail heads so we could position/rotate the axles for best fine adjustment of steering.

I'm not too steady free-handing a Dremel and a nail for this so I came up with the following setup.

If you didn't know the Dremel tools have a threaded nose to mount it to things (it is under a removable trim ring) allowing me to fix the disc in a fixed location.

I used the drill press to precisely hold and lower the nail head with steady orientation onto a spinning cutting abrasive wheel (Don't turn on the drill press!!!!)




Voila!



Tooting my own horn, I felt pretty clever. Worked like a champ!

[LCHIEN]

Got everything pretty much completed, painted, weight corrected and tested and tuned a bit.

Avoided last year's mini disasters by doing in the correct order... paint, drill axel holes, weigh instead of painting last which threw off the weight and lost the precision axle holes. But it required more back and forth coordination from the hardware teams and the painting/decoration teams.

Those of you from Texas will know Whataburger. This is the Whatacar. The one on the right is Tiger Attack which is LEGO styled but OMG, no pips allowed he said. (which saved a lot of work!).



Here's a gallery of pictures of the completed cars and boys.

And a short (9 seconds) video clip P1200720.AVI you will have to download to see.

[leehljp]

Someone did an excellent job with the Whataburger scheme! (BTW - Whataburgers are across LA into MS, AL in larger city areas and even one opening soon in the shopping center near me in Southaven MS (Memphis area, which already has a couple.)

"no pips allowed he said."

I'm not sure what does that means?

[dbhost]

Love both of them. I am sure those boys will cherish the memory for the rest of their lives.

[LCHIEN]

Someone did an excellent job with the Whataburger scheme! (BTW - Whataburgers are across LA into MS, AL in larger city areas and even one opening soon in the shopping center near me in Southaven MS (Memphis area, which already has a couple.)



I'm not sure what does that means?

You know LEGO has the pips on top that make them interlock. I'd call them with the "T*t" word but that is perhaps politically incorrect.

He didn't want the pips showing.

[Black walnut]

What do you mean you don't have screw slot files! Great looking cars. Hope they do well. I have had dremels for decades and never knew about the threads, thanks for the educational tip. Oh yeah I don't have screw slot files either.

[capncarl]

I like how you rigged up your own milling machine, creative. Agree, the boys will remember this forever.
Just a thought, do they allow the participants to 3D print the bodywork yet?
Some supply stores (like Hf) sell inexpensive machine vices with indexable x and y axis that are real handy for small shop milling jobs like this and making slots in metal and wood. Just Chuck up small cutter in the drill chuck and you are in business.
good work

[LCHIEN]

What do you mean you don't have screw slot files! Great looking cars. Hope they do well. I have had dremels for decades and never knew about the threads, thanks for the educational tip. Oh yeah I don't have screw slot files either.

The threads on the front of the Dremel tool is a 3/4"-10TPI, hidden under a trim ring; I just used a normal metal working tap like the one below. On the Dremel tool its used for the router-like base attachment.
21/32" recommended drill is what I just looked up; probably 5/8" is fine for wood-I think that is what I used since I don't think I have a 21/32 drill.

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

I wasn't sure if you were pulling my leg about screw slot files. I had to look them up. They do exist.

I think my idea worked pretty well.

[LCHIEN]

I am hoping for a super fast car. In consult with the older grandson, we did all the legal things (except buying the $30 lathed wheels) we could DIY that made engineering sense to me (explaining why it worked to him so he could defend it if needed). Some father-son team has won the last two years with the kids car and they will be back this year. They are the car to beat.