Sine Bar


Sine bar is a precision angle measuring instrument along with slip gauges. The name suggests that Sine bar work on sine principle. A slip gauge used to build up the height of the sine bar.


The required angle is obtained when the difference in height between the two rollers is equal to the sine of the angle multiplied by the distance between the centers of the rollers.

How to measure with Sine bar ?

sine bar gh

Sine Bar is an indirect method of measurement. Sine Bar is working on Sine principle that is the ratio of length between two roller and height differences.


In the above picture, we are taking a very simple case. Height differences angle H1-H2 is zero, so, after calculation, our result is 180 degrees.

Pros & Corns of sine bar

Some Advantages of sine bar are

  1. It is precise and accurate
  2. Its design is quite simple
  3. Availability of Sine bar is high

Some common Disadvantages are

  1. Inaccuracy increase with an increasing angle.
  2. Handling and fixing positions is create problems sometimes.

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