✕DO NOT FORCE THE FIT
- The tuck. Trimming leaves a margin; a blunt stair tool buries it. The knife spine is the wrong instrument and damages the edge it just cut.
- Face-cutting loop pile at volume. That is a guided loop pile cutter's job — not in this store, and the back-cut method above is the honest knife answer.
- Cutting over installed surfaces that must survive.
- Over finished stairs, installed pad, or hardwood that stays, an open point can reach what is underneath; the captured-throat hook blades (42200 in a utility knife, utility line; 67090, industrial line) exist precisely for that case.
- Complements, not rivals: in the open field or starting a mid-goods cut, the hook is helpless and this open blade is the only tool.