The Lingjiatan drill is deliberately lopsided, with both bit ends offset from center. This off-center rotation sweeps a wider arc, carving flared cavities matching the trumpet-bell earring profile perfectly! Using abrasive mineral sand slurry at 1-3 mm depth per hour in jade, craftsmen achieved astonishing 0.5 mm walls through precise control. 🔬
Lopsided drill bit produced flared cavities for trumpet-bell earrings
Site mentioned
📍 Lingjiatan
Key facts
- The Lingjiatan drill is deliberately lopsided, with both bit ends offset from the center of the shaft
- Off-center rotation creates a flared cone-shaped cavity, matching the trumpet-bell earring profile exactly
- Cutting action delivered by an abrasive slurry of hard mineral sand and water
- Smaller offset bit produces a larger flared cavity because off-center rotation sweeps a wider arc
- Drilling rate of 1-3 mm of depth per hour in hard jade provided real-time control over wall thickness
- Minor drilling irregularities were smoothed away in subsequent polishing stages
- 0.5 mm walls achieved through a precisely controlled, mechanically assisted process rather than reckless grinding
Sources
file.ahm.cn:444
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