Sine Bar Tool

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Sine Bar Basics

A sine bar uses trigonometry to create highly precise angles. The distance between the centers of the cylinders (the length) is the hypotenuse of a right triangle.

Fundamental Formula
Height = Length × Sin(Angle)
Angle = Asin(Height / Length)
Best Practices
  • Angles above 45° are less accurate with a sine bar; use a sine plate or other method if possible.
  • Always ensure gauge blocks are wrung together properly for accuracy.
  • Verify the bar is resting on a clean, flat surface (surface plate).
Note: Most sine bars are precisely 5.0000" or 10.0000" between centers.