The ornamental design for a boringmachine, as shown and described.
FIG. 1 is a front view of a boring machine according to the design of the present invention;
FIG. 2 is a back view of the boring machine;
FIG. 3 is a top plan view of the boring machine;
FIG. 4 is a bottom view of the boring machine;
FIG. 5 is a left side view of the boring machine; and,
FIG. 6 is a right side view of the boring machine.
The broken line depiction of the boring machine is included for the purpose of illustrating portions of the boring machine and forms no part of the claimed design.