An engine includes a cylinder block including a cylinder hole, a crank shaft as an offset crank, and a connecting rod that connects the piston and the crank shaft. An inclined surface is provided on an entire circumference of a crank-shaft-side opening edge of one end of the cylinder hole. When viewed in the axial direction of the crank shaft, a boundary line between the inclined surface and the cylinder hole extends towards the other end of the cylinder hole as it extends toward an offset side on which the crank shaft is offset from the center axis of the cylinder hole. The offset crank engine has the entire circumference of the crank-shaft-side opening edge of the cylinder hole chamfered without any bad influence on the sliding surface and posture of the piston to avoid interference between the crank-shaft-side opening edge of the cylinder hole and the connecting rod.

A portable helical milling unit has a tool, an eccentric spindle, an outer sleeve, a sleeve housing, and a plurality of transmission mechanisms used to provide power. The eccentric spindle is detachably provided in an output section of the outer sleeve. Each of the eccentric spindle and the outer sleeve has a pre-set eccentricity. The tool is in connection with an eccentricity adjustment mechanism. The outer sleeve is installed in the sleeve housing. The outer sleeve is in connection with a first transmission mechanism and a third transmission mechanism. The eccentric spindle is in connection with a second transmission mechanism. All eccentric spindles have the same shape, can be installed in the outer sleeve and can be quickly replaced, so as to achieve precise and large-range adjustment of the eccentricity, thereby expanding the aperture range of processed holes, and improving processing quality and efficiency.

A method for manufacturing a rotatable tool body with pockets positioned circumferentially between flutes about a cylindrical body to accept removable cutting inserts and to distribute the circular runout in a fashion among all of the insert pockets to minimize impact on any particular insert and to increase tolerances. A rotatable tool body also includes these features and a method for utilizing such a rotatable tool body is disclosed.

An apparatus for cutting annular corrugations in an interior surface of a cylindrical tube having a cutter head comprising a plurality of cutting teeth; a drive shaft coupled to the cutter head for spinning the cutter head; a mandrel coupled to the cutter head, wherein the mandrel defines a longitudinal axis, wherein an axis of rotation of the cutter head is parallel to, but in a position not coaxial with the axis of rotation of the cutter head; an outer eccentric coupled to mandrel, wherein the outer eccentric rotates the mandrel, wherein the axis of rotation orbits around the longitudinal axis.

Disclosed is an assembling and centering structure for a processing tool, the structure having a clamping handle (10), a processing head (20), and a fastening member (30) for connecting and fixing the clamping handle (10) and the processing head (20). An end face accommodation groove (100) of the clamping handle (10) is formed with a concave part (11) and a centering hole (12). The processing head (20) is formed with a convex part (211) and a centering post (222), the convex part (211) matches the concave part (11), and the centering post (222) matches the centering hole (12). Thus, it can be ensured that after assembly, the central axis of rotation of the clamping handle (10) is in a straight line with the central axis of rotation of the processing head (20).

Disclosed is an assembling and centering structure for a processing tool, the structure having a clamping handle (10), a processing head (20), and a fastening member (30) for connecting and fixing the clamping handle (10) and the processing head (20). An end face accommodation groove (100) of the clamping handle (10) is formed with a concave part (11) and a centering hole (12). The processing head (20) is formed with a convex part (211) and a centering post (222), the convex part (211) matches the concave part (11), and the centering post (222) matches the centering hole (12). Thus, it can be ensured that after assembly, the central axis of rotation of the clamping handle (10) is in a straight line with the central axis of rotation of the processing head (20).

An orbital drilling device includes, on the same frame: a motor rotating a cutting tool on itself; a first, interior, eccentric, receiving the motor, mounted so as to be able to rotate; a second, exterior, eccentric, receiving the first eccentric, mounted so as to be able to rotate; a reference body, secured to the frame, receiving the second eccentric, mounted so as to be able to rotate; a first unit for driving the first eccentric; a second unit for driving the second eccentric, simultaneously with the rotation of the first eccentric; and a controller configured to reproduce any path of the cutting tool in the zone by continuous control of the angular offset between the first eccentric and the second eccentric.

A cutting tool of the present disclosure may include a holder including a pocket, a shim member, a first screw and an insert. The shim member may include a first hole that opens into an outer side surface and an inner side surface. The pocket may include a second hole corresponding to the first hole. The first screw may be inserted into the first hole and the second hole. A first central axis of the first hole may be located ahead of a second central axis of the second hole in a rotation direction.

An orbital drilling device includes, on the same frame: a motor rotating a cutting tool on itself; a first, interior, eccentric, receiving the motor, mounted so as to be able to rotate; a second, exterior, eccentric, receiving the first eccentric, mounted so as to be able to rotate; a reference body, secured to the frame, receiving the second eccentric, mounted so as to be able to rotate; a first unit for driving the first eccentric; a second unit for driving the second eccentric, simultaneously with the rotation of the first eccentric; and a controller configured to reproduce any path of the cutting tool in the zone by continuous control of the angular offset between the first eccentric and the second eccentric.

A cutting tool has a cutting body with a first insert pocket and an indexable cutting insert removably mounted therein. The first insert pocket has a first seat surface with a plurality of first engagement elements and a first support wall transverse thereto. The cutting insert has upper and lower surfaces and a boundary surface extending therebetween. The lower surface has a plurality of lower engaging elements and the boundary surface has a plurality of alternating first and second peripheral surfaces intersecting the upper surface to form first and second upper cutting edges. In each index position with the lower surface in contact with the first seat surface, the first support wall prevents translation of the cutting insert in a first direction, and the first engagement elements eccentrically contact the lower engaging elements to prevent translation of the cutting insert in a second direction perpendicular to the first direction.