Mechanical tools

                                         MECHANICAL TOOLS

      An item or implement used for a specific purpose. A Tool  can be a physical object such as a mechanical tools.    

         

          FILES

          Filing is a method for removing excess material from a work-piece  by using a file which act as a cutting tool. files are available in many shapes and sizes.

PARTS OF A FILE 

• TIP OR POINT   : The end opposite to tang.
• FACE OR SIDE  : The broad part of the file with teeth.
• EDGE                  : The thin part of the file with a single row of parallel teeth.
• HEEL                   : The portion of the broad part without teeth.
• SHOULDER        : The curved part of file which fits into the handle.
• HANDLE             : The part fitted into tang for holding the file.
• FERRULE           :  A protective metal ring to prevent cracking of the handle.

MATERIALS USED 

             Generally files are made of high carbon or high grade cast steel. The body portion is hardened and tempered. The tang is however.not hardened.

TYPES OF FILES USED

1. FLAT FILES 
2. HAND FILES

Flat files : These files are of a rectangular cross section. the edges along the width of these files are parallel up-to two-thirds of the length, and then they are taper towards the point. the faces are double cut and edges single cut. These files are used for general purpose work. They are useful for filing and finishing external and internal surfaces.

Hand files : These files are similar to the flat files in there cross-section. The edges along the width are parallel throughout the length. The faces double cut. One edge is single cut whereas the other is safe edge. because of the safe edge, they are useful for filing surface which are at right angles to surface already finished. Flat files are general purpose files. they are available in all grades. Hand files are particularly useful for filing at right angles to a finished surface.

     

          CHISEL

           The cold chisel is a hand cutting tool used by fitters for chipping and cutting off operations.

Chipping is an operation of removing excess metal with the help of chisel and hammer. Chipped surface being rough, they should be finished by filing.

PARTS OF CHISEL

• Head 
• Body 
• Point or cutting edge

         

MATERIAL USED

          Chisels are made from high carbon steel or chrome vanadium steel. The cross-section of chisel is usually hexagonal or octagonal. the cutting edge is hardened  and tempered.

COMMON TYPES OF CHISELS 

• Flat chisel
• cross-cut chisel
• half round nose chisel 
• diamond point chisel

Flat chisels : They are used to remove metal from large flat surfaces and chip excess metal of weld    joints and castings.

Cross-cut or cap chisels : These are used for cutting key-ways, grooves and slots. 

Half round nose chisels : They are used for cutting curved grooves ( oil grooves ).

     HAMMER

      An engineer's hammer is hand tool used for striking purposes while 

• punching
• bending
• chipping
• straightening
• forging 
• riveting.

MAJOR PARTS OF A HAMMER

   

 The major parts of a hammer are a head and a handle.

 The head is made of drop-forged carbon steel, while the wooden handle must be capable of       absorbing the shock.

• Face
• peen
• cheek
• eye-hole 

The face is the striking portion. slight convexity is given to it to digging of the edges.

The peen is the other end of the head. It is used for shaping and forming work like riveting and bending. the peen is of different shapes like the

• ball peen
• cross peen
• straight peen 

An engineer's hammers are specified by their weights and shape of the peen. their weight varies from 125 gms to 1.5 kg.

The weight of an engineer's hammer, marking purposes, is 250 gms.

The ball peen hammers are used forgeneral works in machine shop.