Spear & Jackson CSP4 No. 4 Smoothing Plane The Spear & Jackson CSP4 smoothing plane is ideal for cabinet work and general joinery. Its cast-iron body makes it extremely durable and you can expect precision every time thanks to its precision milled base and faces. Features: No. 4 Smoothing Plane. Ideal for cabinetwork and general joinery Cast iron body Precision milled base and faces 50mm wide high carbon steel blade Brass adjusting screw Base: Ductile Cast iron painted Gloss Black with ground sides and bottom Specification: Base Length: 248.0 ± 2mm Base Width and Depth: 63 x 42 ± 1mm