Pinewood Derby Book
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SPEED PACKAGE - In the photo above, we show the Speed Package with all the polishing and graphiting materials and tools you will need for a professional lubrication job. To see a discussion of all the Speed Package items, go to the bottom of this page but first read the FRICTION CONTROL section below.
FREE GRAB BAG - And, we supply all the incidental items you will need in the free Grab Bag. To see all the individual items you get in the grab bag click here on Free Grab Bag.
FRICTION CONTROL— You should first read this introduction to friction control and then click on the different products at the bottom of this page to see descriptions of how each product contributes to the overall Speed Package.
Of all the 12 parameters that affect the speed of a pinewood derby car, the coefficient of wheel/axle friction is the most important, but also the most difficult to control. Notice the extensive research topics shown in Chapter 9 - Friction and Lubrication in the big green book. Basically what was uncovered in the research program was that the lowest coefficient of friction results when a monomolecular graphite film can be applied uniformly to the inside of the wheel bore hole and also to the surface of the axle.
Think of the graphite flakes as playing cards. When exposed to air the oxygen molecules in the air coat the flat part of the flakes like you might coat the playing cards with talcum powder. Then the cards are rather slippery and slide over one another more readily. Similarly the oxygen molecules aren't very strongly attached to the flat sides of the thin graphite flakes. They tend to help the flakes slide on each other by acting like tiny roller bearings. But when you examine the edges of the graphite flakes you see some pretty strong electric fields because the regular uniform symmetry of the surface structure has been broken. These fields collect the oxygen molecules very strongly and make them stack up and prevent them from rolling. Its like the talcum powder gets gooey and sticky right on the very edges of the playing cards. So the question becomes how do you get rid of the edges? Well, if we consider playing cards, consider a 1 or 2 inch diameter axle and a similarly sized bore in a large wheel. Then you would wrap one card around the axle so that you could join the ends smoothly so you didn't have any edges. Do the same to the inside of the bore. Then there are no edges to cause the talcum to get sticky and you would have a low coefficient of friction.
So how do you make graphite flakes coat the wheel bore and axle surface this uniformly? The secret (not any more) is to create a monomolecular film, as thin as a soap bubble, on the wheel bore and axle surface. Just like a soap bubble the film can last quite a while, at least enough for several races. We will now describe the products in the Speed Package and how they help to make a monomolecular lubricating film. None of the 3 powders in the speed package are toxic but just like ordinary fine dust breathing an air suspension containing the powders should be avoided.
Click below for detailed information about the products in the Speed Package.
1. Bore polish
2. Super Z Graphite
3. Axle Polish
4. Lube Block (and Pin Vise)
5. Metal Axle File