Preparing a work piece as per given drawing involving measuring drilling, reaming and tapping operation from a given Mild steel (MS) plate.

  1. Objectives:
  • To know the functions of different drilling, reaming and tapping
  • To acquaint with the procedures of drilling, reaming and tapping
  • To develop the confidence in drilling, reaming and tapping
  1. Theory:

Drilling machine is one of the simplest, moderate and accurate machine tool used in production shop and tool room. It consists of a spindle which imparts rotary motion to the drilling tool, a mechanism for feeding the tool into the work, a table on which the work rests. It is considered as a single purpose machine tool since its chief function is to make holes.

reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides. There are also non-precision reamers which are used for more basic enlargement of holes or for removing burrs. The process of enlarging the hole is called reaming. There are many different types of reamer and they may be designed for use as a hand tool or in a machine tool, such as a milling machine or drill press.

Taps and dies are tools used to create screw threads, which is called threading. Many are cutting tools; others are forming tools. A tap is used to cut or form the female portion of the mating pair (e.g., a nut). A die is used to cut or form the male portion of the mating pair (e.g., a bolt). The process of cutting or forming threads using a tap is called tapping, whereas the process using a die is called threading. 

  • Drawing of the Job: 
        Drilling, reaming and tapping                             operation
Fig: Drilling Machine

 

Different parts of a straight & taper shank drill

 

Reamer

 

Tap

 

  • List of Machine and Tools used: 

Machine-Drilling machine with all its accessories like table vice, drill sleeve, chuck, chuck key etc.

The following fitting and drilling tools are used:

  1. Marking and measuring tools:
    1. Steel rule
    2. Try-Square
    3. Scriber
    4. Odd leg caliper
    5. Centre Punches
    6. Calipers
  • Cutting tools:
  1. Drill bit
  2. Reamer
  3. Tap tool
  • Striking tools:
  • Ball Peen Hammer.

 Raw Material: Mild Steel flat piece of size 65mm x 50mm x 6mm.

Working Procedure:

Preparatory:-

  1. Collect and check the raw material for shape and dimensions. Ensure that it is not under size.
  2. Collect drilling, reaming and tapping tools and equipments.
  3. Check the specifications of the drilling, reaming and tapping tools.
  4. Acquaint with the working knowledge of the drilling, reaming and tapping operation.

 Operation:-

  • After completion of sawing and filing operation, measure the dimension of workpiece.
  • Again apply wet chalk on the flat face and let it get dried.
  • Mark position of the holes to be drilled with the help of scale, try square and scriber.
  • Make permanent marks by means of hammer and centre punch.
  • Fix the required drill bit to the spindle of the drilling machine.
  • Fix the job on the vice fitted on the table of the drilling machine.
  • Adjust the position of the hole to be drilled with the drill fitted already to the chuck of the drilling machine.
  • Make the desired holes by drilling operation.
  • Use reaming tool manually to enlarge the drill hole.
  • Then use tapping tool to do the internal thread inside all these holes.

 Observation Table:

  •  Drilling Operation:-

 

Rough job dimensions Drill hole diameter Remarks
Specified Observations
Drilling Tapping Drilling Tapping
           
           
           
           

 Discussion:

Safety Precautions:

Drilling Operation

  1. Check that the drill is properly fixed to machine. We always use higher speed for smaller diameter of drill and vice versa.
  2. See that the drill bit in drilling spindle is running true or concentrically.
  3. Do not hold the work by hand during drilling.
  4. Keep his head back to avoid injury from any moving part of the drilling machine.
  5. Check proper resting of job before drilling.

Reaming operation:

  1. During machining reaming tool should be kept straight.
  2. Use brush to clean the chips, which may have sharp edges.
  3. Use correct hole size (drill bit) otherwise job will not be properly done

Tapping operation:

  1. Handle the tap with care commonly taps are brittle in nature.
  2. Lubricate the tap during operation although there is less heat generation still it will reduce friction and improve machinability.
  3. Break the continuous chip to avoid injury during machining.
  4. Use correct hole size otherwise job will not be properly done.

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