Derive Formulas of Screw Gauge


To derive a formula of pitch of a screw:
   The distance covered by the screw when its head makes a complete rotation = 1 × pitch of the screw.
   The distance covered by the screw when its head makes 10 complete rotations = 10 × pitch of the screw
   The distance covered by the screw when its head makes 'n' complete rotations (x) = n × pitch of the screw
  Pitch of the screw = The distance covered by the screw (x) /No. of complete rotations
made by the head (n).
     


To derive a formula for the least count of a screw gauge:
    The distance covered by the screw when its head makes a complete rotation
    = 1 × pitch of the screw
    The distance covered by the screw when its head makes 1/10 of a complete rotation
    = 1/10 × pitch of the screw.
    Out of N divisions of the head scale, if only one division crosses the index line then the head of the screw makes 1/N of a complete rotation.
    The distance covered by the screw when its head makes 1/N of a complete rotation
    = 1/N × pitch of the screw
    This distance is the smallest distance that can be measured accurately, by the screw gauge when the head contains N divisions on it. So this can be considered as the least count of the screw gauge.
                


   Generally the L.C. of a screw gauge will be 0.01 mm or 0.001 cm. So it is also known as micrometer screw gauge.

No comments:

Post a Comment

EVERGREEN POSTS