chain, wire, (watch) spring
鎍 centers on flexible metal connectors: a chain, a wire, or a coiled spring. All three meanings share the idea of a long, bendable metal object used to link or store tension.
鎍 combines 金 (metal) with 索, which likely contributes the sound and the idea of a rope or cord, suggesting a metal rope or chain.
The left side 金 is metal, and the right side 索 looks like a twisted rope. Picture a metal rope: a chain or wire, or a coiled spring ready to release.
For サク, imagine a sack full of metal chains: sack -> サク, and the heavy chains clink inside.