Scratch-free boring technique for chain piece

The invention discloses a scratch-free boring technique for a chain piece. According to the scratch-free boring technique for the chain piece, two boring tool bits which are fed synchronously are used for machining two shaft holes of the chain piece at the same time, the two boring tool bits are both provided with a main blade used for machining the corresponding shaft hole, and one of the boring tool bits is further provided with an auxiliary blade used for machining a dustproof hole. The scratch-free boring technique for the chain piece comprises the steps that 1, the chain piece is placed on a clamping device and is clamped and fixed; 2, the directions of the main blades of the two boring tool bits are adjusted to be identical; 3, the two boring tool bits are fed until the main blades stretch out of the shaft holes, fine boring of the shaft holes is completed, then primary tool retracting is conducted to enable the main blades to be still located outside the shaft holes and the auxiliary blade to retract out of the dustproof hole, the two boring tool bits stop rotating, and the main blades and the auxiliary blade do not make contact with the chain piece; 4, the directions of the main blades of the two boring tool bits are adjusted so that the main blades of the two boring tool bits can both face the left side or the right side, the chain piece is loosened by the clamping device, the chain piece is moved horizontally towards the main blades in the length direction of the chain piece so that the main blades can avoid the walls of the shaft holes, then the chain piece is clamped by the clamping device, and the two boring tool bits retract.