Trim cutters AKA - Quarter Round Cutters are commonly used to create precise mitre corners for things such as dowels, smoke seals, picture frames, weather seals and other similar applications. They remove the need to use a mitre box, where the stock must be held as you saw it, or a miter saw, which is an expensive piece of equipment when cutting Quarter round.
Quarter round a convex molding with a cross-section in the form of a quarter circle. A variation is a base shoe, a quarter of an ellipse.Most quarter round is of small gauge and relatively flexible. It is typically used as a decorative build-up element in mantels and other architectural features, and at the lower edge of baseboard to hide any gaps between it and a floor. Base shoe is used similarly in flooring applications. Quarter round is produced in hardwood, softwood, engineered wood, and extruded plastic.