Half-Round Concave Cutter — 3/8″ Radius, 3/4″ Width, Pro-Line (1-1/4″ Bore)

Forms a 3/8″ radius bullnose on stair nosing, cabinet edges, handrail components and shelf fronts — the mating half to the half-round convex cutter, which cuts the corresponding flute. Every Freeborn concave cutter carries a .030″ flare, which relieves the cut at the shoulders and lets the bullnose leave the cutter cleanly instead of burnishing at the tangent points. Radius and width move together as the geometry requires: this cutter’s 3/8″ radius spans a 3/4″ width, giving a full half-round on nominal 3/4″ stock — the common case for stair treads and shelf edges. The Pro-Line body runs a 1-1/4″ bore at 4″ diameter on three wings, counterclockwise, in carbide or T-Alloy. The Mini-Pro equivalent is MC-64-006 on a 3/4″ bore at 2-15/16″.