Monday, 12 April 2021

Reed type mechanical comparators

The reed type mechanical comparator is a device used for measuring the objects dimensions. The reed type mechanism is a friction less device for magnifying small motions of the spindle which is connected horizontal to the fixed block.

It consists of a

  • Fixed block
  • Floating block
  • Spindle
  • Pointer
  • Gauging head case
  • Reed
  • Dial indicator


The fixed block of reed type comparator is rigidly fixed to the head case of gauging Floating block which is carries the gauging spindle and is connected horizontally to the fixed block by reeds.

Reed type mechanical comparators
Reed type mechanical comparators

A vertical reed is attached to each block with the upper ends joined together. A linear motion of the spindle moves the free block by reeds.

A linear motion of the spindle is moves with a free block vertically case the vertical reeds on the floating block to tumble past the vertical reed on the fixed block.

However, as these vertical reeds are joined at their upper end, instead of slipping, the movement causes both reeds to swing through an arc and as much wider arc.

Reed type mechanism

The calibration of scale can be done by using a gauge block, which indicates any deviation present on the scale from an initial setting. In reed type mechanism, the range of mechanical amplification is 100 and it is multiplied by the optical lens systems which is available in the range from 500 to 1000.