Fitter Turner Machinist

Least Count of Vernier Caliper in British System: A vernier calipers is a precision measuring (direct) instrument. Vernier caliper is made of Nickel Chromium Steel . The least count of vernier calipers is 0.001” Calculations: Least Count = 1 M.S.D. - 1 V.S.D.   1 Main Scale Division =   1/40"                                        = 0.025" 25 Division of Vernier Scale = 24 Division of Main Scale                                                =24×0.025" 1 Division of Vernier Scale = ( 24 x 0.025 ) /25        ...

Types and Angle of Punch Punches are two types centre punch & prick punch. The angle of prick punch is 30 ° or 60°. The 30° prick punch is used for marking sharp impression on metal.  The 60° punch is used for marking witness mark. So 60° prick punch is called as Dot punch. Centre Punch marks of angle  90°. Prick Punch  : 30°(Sharp impression)  Dot Punch     : 60°( witness mark)  Centre Punch: 90°(marking 90° angle ) The witness mark should not be too close to one another.  The distance of   one dot mark to another dot is 6 mm.