Chapter 7: Machine Shop Estimation – Drilling Operations
7.1 Introduction to Drilling Operations Drilling is a fundamental machining process used to create round holes in a workpiece. It is one of the most widely used processes in manufacturing and plays a critical role in operations like fitting, assembly, and fabrication. Estimating the time, cost, and resources for drilling operations is essential for efficient planning and production control in a machine shop. 7.2 Fundamentals of Drilling Drilling is the process of cutting a hole into a solid material using a rotating cutting tool called a drill bit. The drilling machine or drill press provides the rotational motion and axial feed required to perform the operation. 7.2.1 Common Drilling Machines Bench Drilling Machine Pillar Type Drilling Machine Radial Drilling Machine Gang Drilling Machine Multiple Spindle Drilling Machine CNC Drilling Machine 7.2.2 Types of Drill Bits Twist drill (most common) Spade drill Step drill Center drill Co...