Fitting and instruments, mostly on work benches is

Fitting6.

1IntroductionFitting is the finishing and assembling of parts made inother shops casting, forging, gear making, electric fitting and machining, togetherto make a single required assembly. Some repair maintenance and die punch workis also carried out in fitting shop. Working on components with hand tools andinstruments, mostly on work benches is generally referred to as ‘Fitting work’. The hand operations in fitting shop include marking, filing,sawing, scraping, drilling, tapping, grinding, etc. 6.

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2 Aim The objective of the experimentis to learn the core operations of fitting for a mechatronics engineer andthese are filing, sawing and drilling. Then using this knowledge to file andpolish the workpiece made in casting and forging. Next, drilling hole at thecenter of casting and also making center of forging piece by centering onLathe. Assemble the all parts and ensure that dimension of holes are correct.

 6.3Tools used in Fitting Shop Tools used in fitting and assembling shopare classified as under.1.     Holding tools2.     Measuring tools3.     Marking tools4.

     Cutting tools 5.     Finishing tools6.     Striking tools and 7.     Tightening tools 6.3.1 Holding tools They are used to hold workpiece inplace so that during filling, cutting or other operations the workpieceposition is not disturbed.

 6.3.1.1Bench Vice Work is held firmly between the jaws. Thebody of the vice is made of cast-iron with jaws cap made up of aluminum toprotect finished surface of work. It is most commonly used.   6.

3.1.2V block with clampItis used to hold cylindrical work.

 6.3.1.3C-ClampIt is used to hold work against angle plate,V-block or other surface.

 6.3.1.

4Parallel ClampIt is used to hold small workpiece 6.3.2 Measuring tools Theseare used to measure dimensions of workpiece  6.3.2.1Steel ruleIt is stiff, straight steelstrip having graduations are marked in inches and centimeters. The least countis 1mm. 6.

3.2.1CalipersThese are used with the help of steel rule to check outside andinside measurements.           6.3.2.

2 Vernier CalipersItis used to measure inside, outside diameter and depth. Least count is 0.02mm(mostly).              6.3.2.

3 Outside MicrometerThis isused for measuring small external dimensions accurately.        6.3.2.4 Inside micrometerThis isused for measuring small internal dimensions accurately.              6.

3.2.5 Try Square Try square is used for marking with the help of scriber and testing angles of 90o.    Othermeasuring tools include feeler gauges, radius gauges etc.

  Non –precision instruments Precision instruments Length and diameter measurements ·       Steel rule   ·       Calipers   ·       Dividers     ·       Micrometers   ·       Vernier calipers   ·       Vernier depth gauges   ·       Vernier height gauges   ·       Slip gauges   Angle measurement ·       Protector   ·       Engineers square   ·       Combination Set ·       Bevel protector   ·       Angle gauges      6.3.3 Marking toolsTheyare used to mark dimensions on workpiece. 6.

3.3.1 ScriberA Scriber is a slender steel rod, used to scribe or mark lines onmetal work pieces.

They are called metal worker’s pencil.        6.3.3.2 Odd-leg caliperThis isalso called ‘jenny caliper’ or ‘hermaphrodite’.

This is used for markingparallel lines from a finished edge and also for locating the centre of roundbars. 6.2.

3.3 DividerThisis used for marking and drawing circles and arcs on metal sheet. 6.3.3.3 Dot Punches Thisis used to locate center of holes and to provide a small center mark fordivider point etc.

There are different dot punches: center. drift, letter, andnumber punch   6.3.4 Cutting tools 6.3.4.1Hacksaw The hacksaw is used for cuttingmetal by hand. The number of teeth per inch (TPI) is selected on the basis ofthe work material and thickness being cut.

     6.3.4.2 ChiselsChisels are used forremoving extra metal or for cutting thin sheets.

A flat chisel is a commonchisel used for chipping and cuffing off thin sheet-metal.A cape chisel is narrowshaped tool. It is cased mostly for the chipping grooves and keyways.   6.3.4.

3 Taps and Tap WrenchesTaps are used for cuttinginternal threads after drilling holes. They are used with wrench and the systemis rotated clockwise. For internal threads the drill is kept slightly small.5mm thread so 4.5mm drill.

Hand taps are usually madein sets of three 1.     Rougher2.     Intermediate 3.     Finisher respectively.     6.

3.4.4 Dies and Die-holders Dies are cutting toolsused for making external threads. They are used with die holder.       6.3.4.5 DrillA drill is a tool for makingholes in a metal which are used for assembling purposes.

 6.3.5 Finishing tools 6.3.5.

1 Files Files are widely usedfinishing tools in Workshop. They remove small amounts of material from thesurface of a workpiece. They are used to cut, smooth or fit metal parts. They usuallyhave diagonal teeth. Classification according to shape, cutting andpitch or grade of the teeth.  1.     single cut teeth files: have rows of teeth in one direction                                                    2.

     double cut teeth files. Have second row of teeth cutting diagonally the first.3.

      Parts of File:1.     Point: it is starting end file. File is heldwith two fingers below and thumb above the point2.     Edge: is side of a file which has no teeth3.     Face: it smoothens the job4.    Heel:The heel is next to the handle5.

     Tang: The pointed part is which fit into thehandle.6.     Handle: Opposite to pointTypes of files:1.    Hand file: used to file surface at right angle to an already finishedsurface.2.

    Flat files: It is Rectangular in sectionand tapered for 1/3rd length in width and thickness. Used to fileflat surfaces. It is general purpose file. 3.

    Triangular file: Equilateral triangular in section and taperedfor 1/3rd length on all faces. Used for filing internal corners between 60° and 90°.4.     Roundfile: it iscircular cross section and tapered for 1/3rd length. Used to openout holes and round inside corners.

5.     Square file faces. It is Square in section and tapered for 1/3rd lengthin all faces. Used for filing corners and slots, and cuting keyways.