halberd
槊 refers to a type of long polearm, specifically a halberd. It is a weapon combining a spearhead with an axe-like blade.
槊 combines 木 (wood) with 朔, which likely contributes the sound. The character originally referred to a long wooden shafted weapon.
The top 朔 suggests a crescent moon shape, and the bottom 木 is wood. Imagine a wooden pole topped with a crescent-shaped blade: a halberd.
For サク, picture a soldier using a halberd to cut open a sack of supplies: sack -> サク, and the blade slices through.