A lathe loading clamp for supporting bars includes a main body provided with a shaft for coupling to a rotating assembly, which is substantially tapered at one of its ends, and a cavity at the opposite end. The cavity accommodates, with a predefined axial play, a bush, made of material that is at least partially polymeric, which has an axial channel having a diameter that is substantially complementary to the diameter of the bar to be supported. The axial channel (6), in the configuration for use, accommodates a portion of a bar.

A production method for a ring-shaped part is provided with: an inner cutting step for reciprocating a first cutting blade in the radial direction D4 from a state of contact with the center of the thickness of one end 91a of a rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the inner circumferential R1-side of the cylindrical blank 91; an outer cutting step before, after or simultaneously with the inner cutting step for reciprocating a second cutting blade in the radial direction D4 from a state of contact with the center of the thickness of the one end 91a of the rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the outer circumferential R2-side of the cylindrical blank 91; and a separation step after the inner cutting step and the outer cutting step for cutting the portion 92 of the cylindrical blank 91, the inner circumferential R1-side and the outer circumferential R2-side of which have been cut, from the remainder 93 of the cylindrical blank 91 to obtain a ring-shaped part 94 with a roughly circular cross-section.

A cryogenically cooled boring tool design reduces the effect of cryogen coolant on a workpiece caused by coolant leakage and coolant exhaust. A tool body has a cartridge for holding a cutting tool insert and a coolant supply path through the tool body and the cartridge for supplying cryogenic coolant to the tool insert. A feed transfer tube connects the coolant supply path in the tool body to the coolant supply path in the cartridge. Insulating tubes line portions of the coolant supply paths in the tool body and the cartridge. The shrinkage rates of the feed transfer tube and the insulating tubes cause the press fit of the insulating tubes to tighten the seal between the insulating tubes and the feed transfer tube when cryogenic coolant flows through the supply path. The exhaust ports on the tool for boiled-off cryogen remains outside of a workpiece bore.

A production method for a ring-shaped part is provided with: an inner cutting step for reciprocating a first cutting blade in the radial direction D4 from a state of contact with the center of the thickness of one end 91a of a rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the inner circumferential R1-side of the cylindrical blank 91; an outer cutting step before, after or simultaneously with the inner cutting step for reciprocating a second cutting blade in the radial direction D4 from a state of contact with the center of the thickness of the one end 91a of the rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the outer circumferential R2-side of the cylindrical blank 91; and a separation step after the inner cutting step and the outer cutting step for cutting the portion 92 of the cylindrical blank 91, the inner circumferential R1-side and the outer circumferential R2-side of which have been cut, from the remainder 93 of the cylindrical blank 91 to obtain a ring-shaped part 94 with a roughly circular cross-section.

A cryogenically cooled boring tool design reduces the effect of cryogen coolant on a workpiece caused by coolant leakage and coolant exhaust. A tool body has a cartridge for holding a cutting tool insert and a coolant supply path through the tool body and the cartridge for supplying cryogenic coolant to the tool insert. A feed transfer tube connects the coolant supply path in the tool body to the coolant supply path in the cartridge. Insulating tubes line portions of the coolant supply paths in the tool body and the cartridge. The shrinkage rates of the feed transfer tube and the insulating tubes cause the press fit of the insulating tubes to tighten the seal between the insulating tubes and the feed transfer tube when cryogenic coolant flows through the supply path. The exhaust ports on the tool for boiled-off cryogen remains outside of a workpiece bore.