Authentic Easy Wood Tools Ci1-R4 Square Carbide Replacement Cutter with 4" Radius for Full and Pro Size Roughers Lathe Woodturning Tools Ci1-R4 Authentic Easy Wood Tools 100% manufactured in the USA by the leader in carbide insert lathe woodturnings technology Ci1-R4cutter designed to fit full and pro size roughers; .580" square by .100" thick, 8-32 screw The perfect grade of carbide produces the best combination of sharpness and durability Optimal grinding process produces the flattest and truest cutting surfaces The right geometry or cutting angle is ground to the produce an edge the cuts cleanly and safely.