make fire by rubbing sticks
鑽 centers on the act of creating fire through friction, specifically by rubbing sticks together. The meaning is narrow and concrete, describing an ancient fire-starting technique.
鑽 combines 金 (metal) with 贊, which likely contributes the sound. The character originally referred to a metal tool used for drilling or boring, and by extension the act of making fire by friction with such a tool.
The left side 金 suggests a metal tool, and the right side 贊 looks like a complex mechanism. Picture a metal drill-like stick being rubbed vigorously against wood to create fire.
For サン, imagine the sun (サン) being born from the friction of rubbing sticks: the sun's fire is created by 鑽.
diligent study; devoting oneself to one's studies
hand drilling (to start a fire); hand drill; rubbing sticks to make a fire
to apply oneself (to one's studies, research, etc.); to devote oneself to study; to pursue one's studies with dedication
self-improvement
boring; drilling
to start a fire (with wood-wood friction or by striking metal against stone)
boring; punching
punched tape; (perforated) paper tape
boring machine; punching machine; perforator