Boring Head helps in the process of enlarging a hole that has already been drilled (or cast), by means of a single-point cutting tool. Boring head is used to achieve greater accuracy of the diameter of a hole. hnical Details: Robust Construction to withstand stresses Least Count: 0.02mm (Standard Model) Least Count: 0.01mm (High Accuracy Model) With Extra Boring Tools Range: 20-80mm, 50-150