The quarter moon knife is the perfect tool to cut straight lines precisely on thick leather. I ordered mine to be custom made by a local artisan. This knife is a nice alternative to half moon knives. For straight cuts, the long blade can be used to cut then push the knife through the length of the line. For curves, the curved part of the long blade can be used to cut by pressure, like a roller cutter except that it is the leather that will move around the blade while the operator will have to jiggle the blade front and back.
Then the small blade, the one on top of the tool, is useful to make rough cuts. This one is used by pulling the knife like a regular cutter but offer a stronger, more rigid slide on the material.
