ITI Bangla

        Types of Marking Punch Punches are used in order to make certain dimensional features of the layout permanent. There are two types of punches. They are centre punch and prick punch made of high carbon steel , hardened and ground. Centre Punch : The angle of the point is 90° in a centre punch. The punch mark made by this is wide and not very deep. This punch is used for locating centre of the holes . The wide punch mark gives a good seating for starting the drill. (Fig 1a ) Prick Punch/Dot punch : The angle of the prick punch is 30° or 60°. (Fig 1b) The 30° point punch is used for making light punch marks needed to position dividers. The divider point will get a proper seating in the punch mark. The 60° punch is used for marking witness marks and called as dot punch. ( Fig 2)

    Hacksaw Frame and Blade                                                                Hacksaw : a hacksaw frame is used along with blade to cut of different sections and  is specified by the type and  maximum length of the blade that  can be fixed . Example.   Adjustable hacksaw frame-tubular-250-300 or 8"-12" Types of hacksaw fram  SOLID FRAME : Solid frame only a  blade of the particular standard   length can be fitted to this frame.  eg. 300mm for 250mm.   Adjustable frame (flat type) :   Different standard length of blades can be fitted to this frame.  example:  250 mm and 300mm.   Adjustable frame (Tubular type) : this  is  the most common used type.  It gives a batter grip and control,  while swaing.   Parts of a hacksaw frame  1) Handle 2) Frame 3) Tubular frame with holes for length adjustment  4) Retaining pins  5) Fixed blade-holder  6) Adjustable blade-holder  7) wing nut  A hacksaw blade is made of either Low alloy steel(LA) or High speed  steel (HSS) and

                      Try Square  The try square is used to Check the squareness.  The Blade is fixed to the stock at 90 Degree.  *Try Square is specified by length of the Blade *The accuracy of Square  square is about 0.002mm per 10 mm length . * Try Square is made of hardend Steel .  The try square is used to- 1) Check the squareness of machines  2) Check the flat Ness. & 3) mark line at 90 Degree.

  Reamer Which Tool is used for enlarging by finishing previously drilled holes to accurate size - Reamer Which taper shank is used for machine reamer to hold on machine spindle - M.T  Hand Reamer is used to the ream holes manually using - Tap wrench. The angle between the edges and the reamer axis is called - hELIX ANGLE. WHICH REAMER IS USED FOR REAMING MORSE TAPER HOL E - SOCKET. A Taper pin reamer is made with a taper of - 1 in 50. Which Flute reamer is suitable for reaming holes with key way grooves - Helical flutes reamer.   The cutting portion of reamer is made of - H.S.S. The Shank portion of reamer is made of - Carbon steel 

                                                       HACKSAW                                      A hacksaw blade is made of - Low alloy steel or high alloy steel. What is the standard length of hacksaw - 250mm to 300mm What is the pitch of the blade - the distance between adjacent teeth is known as the pitch . How many types of pitch of Hacksaw -   Coarse 1.8                                          -  Medium 1.4-1.0                                          - Fine 0.8mm Type of set -----------------------------------  Pitch Wave set --                                            0.8mm Wave and Staggered --                         1.0mm Staggered set --                                    Over 1.0mm The selection of the blade depends - On the shape and hardness of the material to be cut . For Bronze, Brass, Soft steel, Cast iron, Heavy angles used - 1.8mm pitch. For Tool Steel , High carbon steel , Hss Used - 1.4mm Pitch. Brass tubing

                                               (COMPUND OF METAL ) 1 ) Brass = Cu 70% + Zn 30 % 2 ) Munz Metal = Cu 60% + Zn 40%  3)  Dutch Metal = Cu 80% + Zn 20% 4) Bronze Metal = Cu 90% + Sn 10% 5) Monel Metal; = Cu 70% + Ni 30% 6) Roolled gold = Cu 90% + Al 10% 7) Bell Metal = Cu 80% + Sn 20% 8) German Silver = Cu + Zn + Ni 9) Delta Metal = Cu60% + Zn 38% + Fe 2% 10 ) GUN Metal = Cu 10% + Sn 1% + Zn 1% + Pb88% 11 ) Stainless steel = Fe 75% + Cr15% + Ni10% + C 12 ) Nickel steel = Fe 95% + Ni 5% 13 ) Nichrome + Ni+ Cr + Mn + Fe 14 ) Solder = Pb 50% + Sn 50% 15 ) Mangnalium = Al 95% + Mg 5% 16 ) Duralumin = Al 64% + Cu 3% + Mg2% +Mn1%