Table of Contents

Basic and related Drilling machine Operations

Drilling machines are used for not only drilling the hole but also operations related holes can be performed on drilling machine. Some operations are explained here

DRILLING OPERATIONS

1) Drilling.

It is an operation of producing a circular hole in a work piece by forcing a drill against it.

2) Boring.

It is an operation of enlarging a hole that has already been drilled by a single point tool, so as to make it true to required size.

3) Reaming.

It is an operation of slightly enlarging a machined hole to proper size with a smooth finish. The reamer is an accurate tool and is not designed to remove much metal. The reaming allowance is usually 0.2 mm only.

4) Tapping.

It is an operation of producing internal threads in a hole by means of a tool called tap.

5) Counter boring.

It is an operation of enlarging the mouth of a drilled hole to set bolt heads and nuts below the surface so that they may not project out from the surface level.

6) Spot facing.

It is an operation to finish off a small portion of rough surface around a drilled hole to provide smooth seat for bolt head. Spot facing tool is a single blade; ground to give two cutting edges and is guided by a stem which run in a pilot hole.

7) Counter-sinking.

It is an operation to bevel the top of a drilled hole for making a conical seat for a flat head screw. Ordinary flat drill ground to correct angle is used for countersinking holes.