kind of pen, kind of chisel
錡 centers on a metal tool used for cutting or shaping: a kind of pen or chisel. The two given meanings are specific types of such a tool.
錡 combines the metal radical 金 with the phonetic component 奇. The exact historical development is uncertain, but it likely originally referred to a metal tool or implement.
The metal radical 金 on the left suggests a metal tool. The right side 奇 looks unusual or strange—imagine a peculiar metal pen or chisel that stands out among ordinary tools.
For キ, imagine a key-shaped chisel made of metal: key -> キ, and you use this key-like tool to carve or cut.