✕DO NOT FORCE THE FIT
- Throwing beds. No rectangle throws a bed joint; laying is the 10" patterns' work (18090/18095).
- Striking mortar joints on walls. A flat blade can slick a flat joint on flatwork, but the concave weather-shedding profile is the jointer's (18170/18182) — a margin trowel dragged down a wall joint leaves a flat smear that sheds water worst.
- Notched-thinset spreading. Tile beds want notched trowels (tile line); the margin trowel mixes and back-butters, then hands off.
- Production mixing. A wheelbarrow of mortar wants a hoe; a bucket of thinset for a floor wants a drill paddle. This is the small-batch instrument, and the boundary is quantity, not competence.
- Prying. Forged one-piece takes abuse better than most, and every pried lid still spends corner squareness the mixing job needed.