Grand Prix Racing - | How To Make A Fast Pinewood Car |
Removing hub spurs and polishing your axles can cut friction in half when a lubricant is used. Grinding them may not reduce it any further. However, both polishing and grinding require work with a drill, steel wool composite, polishing compound or grinding medium. Gloves come in handy if you do not have a jig to hold abrasive material.
Hub spurs are small triangle-shaped "ribs" that extend from the axle shaft to the underside of the hub.
AWANA: There are four on each AWANA kit axle. Most competitors over look them because they are so small. |
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BSA: No one misses the two large ones on each Boy Scout axle. In some cases, they must be removed before the wheel can even spin! |
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You can remove the spurs when you polish your axles. Use a file with its flat face against the underside of the hub as you spin the axle according to the instructions for polishing.
Polishing is fairly simple to do. Even if you just use steel wool, some benefit can be gained. The paint section of your local hardware store sells pads for polishing metal. Often they have steel wool fibers in them along with other fibers that help make the surface smooth and even. To avoid ridges and burrs, use a metal or jeweler's polishing compound. If you grind your axles to reduce their diameter, you will still need to polish them.
Time saver
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In the procedure below, each axle is turned while grinding. This action causes burrs to develop that make the wheel spin faster in the direction of grinding. If you do not use a polishing compound when you later polish your axles, axles from opposite sides of the car will need to be ground in opposite directions. A reversible drill is needed to achieve this.
You will need a grindstone made of tough material. Those that can be purchased for dremel-type hobby tools make little progress on kit axles. Some Grand Prix competitors use high-speed grinders to thin the axle on opposite sides. The axle must still be polished to remove burrs. Mounting must be done with care so an unground edge of the axle makes contact with the bottom, inner surface of the wheel's bore.
Theory shows that thinner axles are probably better than thicker ones only when the wheel bore is also narrowed. Thin axles can bend undesirably. |
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As long as even pressure is applied along the stem from the hub and out about 3/8 inch from the hub, a good result can be obtained.
If you slope the back of the hub with a small file, don't over do it. Excessive "coning" can act as a cork in the borehole of the wheel and increase friction. On the other hand, a flat back on the hub can be bad if the wheel has roughness in the hub area.
The right side of the car is the right side of the car when the car is facing you front first.
Looking at the axle with the hub end pointed away from you,
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Grand Prix Racing - | How To Make A Fast Pinewood Car |
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