How to Burnish Pinewood Derby Axles with Graphite + Moly
Burnishing is the final mechanical step before assembly. This process embeds a thin, uniform layer of Derby Dust® Graphite + Moly into the microscopic pores of the metal, creating a long-lasting, low-friction surface. Proper burnishing improves speed and consistency through every heat.
Tools and Materials
- Low-RPM drill or pin vise (200–400 RPM recommended)
- Derby Dust® Graphite + Moly Dry Lube
- Clean 100% cotton T-shirt scrap or cotton butcher’s string (no synthetic fibers)
- Soft cloth for cleanup
- Safety glasses
1. Mounting
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Insert the axle head-out into the drill chuck, only ½" exposed.
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Set drill to LOW speed (under 300 RPM) or use a pin vise.
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The drill must be secured upright or clamped — never handheld against your body.
2. T-Shirt Burnish Method (Recommended for Beginners)
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Use a 2" × 6" strip of clean 100% cotton T-shirt.
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Pinch both ends of the strip well behind the spinning shaft (6–8 inches away).
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Rest the cloth lightly over the shaft — do not loop it around.
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Let the axle spin under the cloth’s tension.
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Apply light pressure and move the cloth side-to-side, never wrapping or trapping the cloth around the axle.
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Release immediately if resistance is felt — the cloth should glide freely.
⚠️ Never pinch or twist directly around the shaft; always keep an open “V” of cloth so it can release if caught.
3. Cotton Butcher’s String Method (Advanced)
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Cut a 12–14" length of string.
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Dust with Derby Dust® Graphite + Moly.
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Lay it gently across the spinning axle and hold each end loosely — no wraps, no knots.
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Allow only one light crossing contact point on the shaft.
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Keep your hands a full 6 inches away from the rotating section.
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If the string catches, simply let go — it will sling free harmlessly.
4. Safety Checklist
✅ Keep sleeves, jewelry, and long hair secured.
✅ Use eye protection.
✅ Stop immediately if vibration or grab occurs.
✅ Never burnish bent or cambered axles — straighten, polish, burnish, then bend.
Final Steps
- Remove the axle from the drill and set aside without touching the burnished surface.
- Only after burnishing should any alignment bends be made using your preferred camber or rail-rider setup.
- Store finished axles in a clean, dry tube or bag until installation to prevent contamination.
Finish Indicators (After 3000-Grit Polish + Burnish)
| Axle Material | Visual Finish | Tactile Feel | Notes |
|---|---|---|---|
| Raw Steel | Gunmetal-gray satin | Slightly waxy, very slick | Graphite layer visibly fills grain of metal |
| Zinc-Plated | Uniform dull silver | Dry-slick, low grab | Graphite bonded into pores of zinc |
| Nickel-Plated | Mirror silver with faint gray hue | Ultra-slick, zero drag | Thin bonded moly film over graphite micro-layer |
Burnishing locks the lubricant into the microscopic structure of the metal. Done correctly, this film can survive many heats without re-lubing, maintaining smooth wheel float and repeatable times.
