Drilling

Introduction

Drilling

Drilling is the operation of generating a hole or enlarging an already existing hole. Usually the second operation is known as boring. Drilling is one of the most important metal cutting operations. It is performed on a drilling machine, lathe or milling machine by using a two lipped or sometimes a multi teeth cutting tool called “drill”. As the drilling machine exerts vertical pressure to originate a hole, it is loosely called a drill press.

Types of Drilling Machines

Drilling machines are made in many different types of sizes, each designed to handle a specific type of job to the best advantage. The different types of drilling machines are:

v Hand drilling machine

v Portable drilling machine

v Sensitive drilling machine

v Bench drilling machine

v Vertical column drilling machine

                     (or)

Upright drilling machine

              (or)

Pillar drilling machine

v Radial drilling machine

§  Plain

§  Semi universal

§  Universal

v Gang drilling machine

v Multi spindle drilling machine

v Deep hole drilling machine

v Horizontal boring machine

v Jig boring machineHand Drilling Machine   

1. Hand Drilling Machine

Hand Drilling Machine

By this machine holes are drilled by rotating the drill by head. It is used for drilling small holes in wood, plastic,soft metals and sheet metal. The machine can be carried to any place easily. Its capacity is 6mm.

2.Portable Drilling Machine

Portable Drilling Machine

   By this machine drilling is done by holing it in hands but drill is rotated by electric power. Therefore, bigger diameter holes even in steel can be drilled. It is mostly used for drilling holes in some jobs which are not possible to do in other machines. For example, assembly work. Its capacity is up to 10mm.

3. Sensitive Drilling Machine

Sensitive Drilling Machine

   This is a small but sturdy machine designed by very small diameter at high speed. It is usually mounted on a bench. Its capacity is up to 6mm. Its spindle can rotate up to 20000 RPM and above.

4. Bench Drilling Machine

Bench Drilling Machine

This is a precision drilling machine commonly used in tool rooms. It is mounted on a bench. Its capacity is 13mm.

5. Pillar Drilling Machine

Pillar Drilling Machine

This is known by several names like upright drilling machine, vertical drilling machine etc., This is a large and heavier machine compared to bench drill and it is mounted on floor. It is designed to handle medium jobs in tool rooms. Its capacity is up to 25mm. Also it is provided with auto feed.

6. Radial Drilling Machine

Radial Drilling machine

   This is a heavy duty drilling machine used for drilling on medium to large and heavy jobs. This machine consists of a round vertical column which is mounted on a large desk. A radial arm sli9des up and down on the round column and can also be swiveled to any angle is 360⁰ around the column and clamped in that position. The radial arm carries the drilling head with a motor. The drilling head can slide along the radial arm and can be fixed in any position. Thus the three movements combined any hole can be located in any position. In addition to this some machines have provision to drill holes at an angle also.

7. Gang Drilling Machine

Gang Drilling Machine

    This machine has two or more independent spindles. Each arm separated head in a line with a common table. Each spindle has its own drive and it can be run at speeds and feeds independent of the other spindles. It is mostly used for production work.

8. Multi Spindle Drilling Machine

Multi Spindle drilling Machine.

This is strictly a mass production drilling machine intended for the rapid production of many holes of varying diameters on a single work piece. All the spindles run with a single motor and operate at the same time.

9. Deep Hole Drilling Machine

Deep Hole Drilling Machine

     This is a special drilling machine for drilling deep holes in gun barrels, crank shafts, long shafts etc., on this section the work piece supported at several points and rotated. The drill is fed in to the work. Provision is made to pump sufficient amounts of coolant to the cutting edges. In some machines both the drill and work are rotated. The machine may be horizontal or vertical. In some machines step feed is applied, that means the drill is withdrawn automatically each time when it moves into the work equal to its diameter for clearing the chip from the work.

10.Horizontal Drilling Machine

Horizontal Drilling Machine

    Horizontal boring mill is the common name for the horizontal boring drilling and milling machine. Machines of this class can do drilling, boring, reaming, turning, threading, facing, milling and other operations on work pieces that are too bulky, irregular an unsymmetrical or too heavy to be rotated. The spindle of this machine is in horizontal direction and bed is parallel to the spindle axis.

11. Jig Boring Machine

Jig Boring Machine

      Jig boring machine or jig borer as it is usually called. This is a high precision machine tool. It is used for locating and machining holes with higher accuracy of one micron. Although the single point boring bar is the important tool used on this machine. Drills, reamers and counter bores are also used. A jig borer has the essential elements of a vertical spindle milling machine, but is lower to the floor and much more rigid and accurate construction. It is kept in air conditioned rooms to help using the full accuracy of the machine.