Abstract: A helical blade cutter including multiple linear blades attached to an outer circumferential surface of a round body having an outer surface formed into a cylindrical circumferential surface. The blades tilt to a given helix angle ? from a straight line on the outer circumferential surface parallel to a rotational central axis O. Blade attachment surfaces are formed on the outer circumferential surface of the round body at given intervals in the circumferential direction. The blade attachment surfaces tilt to an angle same as the helix angle ? of the blade while tilting to a rake angle ? in a direction of an elevation angle from a tangent to the outer circumferential surface. The blades are each attached to a blade attachment part through intervention of a chip holder that allows detachment of the blade.

Abstract: A helical blade cutter including multiple linear blades attached to an outer circumferential surface of a round body having an outer surface formed into a cylindrical circumferential surface. The blades tilt to a given helix angle ? from a straight line on the outer circumferential surface parallel to a rotational central axis O. Blade attachment surfaces are formed on the outer circumferential surface of the round body at given intervals in the circumferential direction. The blade attachment surfaces tilt to an angle same as the helix angle ? of the blade while tilting to a rake angle ? in a direction of an elevation angle from a tangent to the outer circumferential surface. The blades are each attached to a blade attachment part through intervention of a chip holder that allows detachment of the blade.

Abstract: The known traveling steel pipe cutting machine of a milling type, which cuts a pipe while traveling in synchronism with a pipe manufacturing speed, is improved so as to facilitate the calculation of positional loci and the control of a milling cutter, to increase a rigidity of the machine and a life of the cutter, and to also make it possible to cut even a pipe having an asymmetric cross-sectional shape under the same set of operating conditions. A plurality of cutter heads each include a milling cutter, and are each supported and linearly fed in biaxial directions by respective guides and feed drive motors. A clamping device is positioned in the proximity of the milling cutters for holding and fixing the pipe. The cutter heads and the clamping device are disposed on a traveling truck.