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Construction Of Drilling machine and Application Of Drilling Machine

Introduction To Drilling Machine

Drilling is  an  operation of making a  circular hole  by  removing a  volume of metal from the  job by cutting tool called drill. A drill  is a rotary end-cutting tool with one or more  cutting lips  and  usually one or more  flutes for the  passage of chips  and  the  admission of cutting fluid. A drilling machine is a machine tool designed for drilling holes  in metals. It is one of the  most important and   versatile machine tools  in  a  workshop. Besides drilling round  holes, many other operations can   also  be  performed on  the   drilling machine such   as  counter- boring, countersinking, honing, reaming, lapping, sanding etc

Basic purposes Of Use of drilling machines

Drilling machines are generally or mainly used to originate through or blind straight cylindrical holes in solid rigid bodies and/or enlarge (coaxially) existing (premachined) holes :

Of different diameter ranging from about 1 mm to 40 mm
• Of varying length depending upon the requirement and the diameter of the drill
• In different materials excepting very hard or very soft materials like rubber, polythene etc.


Construction Of Drilling machine
Drilling Machine Diagram
In drilling machine the drill is rotated and fed along its axis  of rotation in the  stationary workpiece. Different parts of a drilling machine are shown in  Fig.   and  are  discussed below: 

 (i) The  head containing  electric motor,V-pulleys and  V-belt  which transmit  rotary motion to  the  drill  spindle at a  number of speeds. 

(ii)  Spindle is  made up  of alloy  steel. It rotates as  well  as  moves  up  and  down  in  a  sleeve. A pinion engages a  rack fixed  onto  the sleeve  to provide vertical up  and  down  motion of the spindle and  hence the  drill  so that the same can  be fed into  the  workpiece or withdrawn from  it while drilling. Spindle speed or the drill  speed is changed with the  help  of V-belt  and  V-step-pulleys. Larger drilling machines are having gear boxes  for the  said  purpose. 

(iii)  Drill  chuck is held  at the  end  of the  drill  spindle and  in  turn it holds  the  drill  bit.  

(iv) Adjustable work  piece  table is supported on the  column of the  drilling machine. It can  be moved  both  vertically and  horizontally. Tables are  generally having slots  so  that the  vise  or  the workpiece can  be  securely held  on  it. 

(v)  Base  table is a heavy casting and  it supports the  drill  press structure. The  base  supports the  column, which in turn, supports the  table, head etc. 

(vi) Column is a vertical round or box section which  rests on the  base  and  supports the  head and the  table. The  round column may  have rack teeth cut on it so that the  table can  be raised or lowered depending upon  the  workpiece requirements. This  machine consists of following parts.

1.   Base
2.   Pillar
3.   Main drive
4.   Drill  spindle
5.   Feed  handle
6.   Work  table

How Drilling Machines are Classified ?

Different parameters  are   being   considered for  different types of drilling machines to determine their size.  The  size  of a portable drilling machine is decided by the  maximum diameter of the  drill  that it can  hold.  The  sensitive and  upright drilling machines are specified by the  diameter of the  largest workpiece which  can  be centered under the  drill machine spindle. A radial drilling machine is specified by the  length of the  arm and the diameter ofthe column. To specify  a drilling machine completely, following other parameters may  also  be  needed:
1.   Table diameter
2.   Number of spindle speeds and  feeds  available
3.   Maximum spindle travel
4.   Morse  taper number of the  drill  spindle
5.   Power input
6.   Net  weight of the  machine
7.   Floor   space required, etc.

Application Of Drilling Machine:
The wide range of applications of drilling machines include :

• Origination and / or enlargement of existing straight through or stepped holes of different diameter and depth in wide range of work materials – this is the general or common use of drilling machines

• Making rectangular section slots by using slot drills having 3 or four flutes and 1800  cone angle
• Boring, after drilling, for accuracy and finish or prior to reaming
• Counterboring, countersinking, chamfering or combination using suitable tools. 

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