# Trig: Sine Bar Applications 225

This class explains how to use the sine bar for machining and inspection purposes and explains step-by-step examples for using trig ratios and the sine bar to find missing information.

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## Class Details

Class Name:
Trig: Sine Bar Applications 225
Description:
This class explains how to use the sine bar for machining and inspection purposes and explains step-by-step examples for using trig ratios and the sine bar to find missing information.
Version:
1.0
Difficulty:
Intermediate
Number of Lessons:
14
Additional Language:
Spanish, Chinese
Related 2.0 Class:
Trigonometry: Sine Bar Applications 221

## Class Outline

• Objectives
• Sine, Cosine, and Tangent
• What Is the Sine Bar?
• The Purpose of the Sine Bar
• Setting the Sine Bar Angle: An Example
• Determining Gage Block Size
• Determining the Sine Bar Angle
• Determining the Gage Pin Height
• Checking Dimensions: Sample Part
• Sample Inspection: Right Triangle #1
• Sample Inspection: Right Triangle #2
• Sample Inspection: Right Triangle #3
• Sample Inspection: Solution
• Summary

## Objectives

• Identify the three most common trig ratios.
• Describe the sine bar.
• Describe common applications for a sine bar.
• Explain how to set up a sine bar angle.
• Determine the gage block size for a specific sine bar angle.
• Determine the measurement of the sine bar angle using a gage block height.
• Explain how a gage pin helps you measure distances and edges on a part.
• Find the information in the shop print to help you begin measuring a part on a sine bar.
• Use a trig ratio to find missing information in the sample problem.
• Solve for the total part height in the sample problem.

## Certifications

MSSC
• MSSC Quality Practices and Measurement

## Glossary

Vocabulary Term Definition
cosine In a right triangle, the ratio of the length of the side adjacent to the angle divided by the hypotenuse.
gage block A hardened steel block that is manufactured with highly accurate dimensions. Gage blocks are available in a set of standardized lengths.
gage pin A cylindrical pin often used with the sine bar, which helps determine a range of precise measurements. A gage pin provides an easily accessible surface and a known height from which you can measure all distances and edges.
height gage A type of measuring instrument with a precision finished base, a beam that is at a right angle to the base, and an indicator.
hypotenuse The longest side of a right triangle. The hypotenuse is always opposite the 90° angle in a right triangle.
reference angle The measured, or known angle in a right triangle other than the 90° angle.
right triangle A triangle containing one angle that measures exactly 90 degrees.
sine In a right triangle, the ratio of the length of the side opposite the angle divided by the hypotenuse.
sine bar A steel bar with a matching cylinder on each end that is used for setting up work at various angles for the machining or inspection of parts. A sine bar is ground and lapped to a high accuracy.
surface plate A hard, flat surface, usually made of granite, which is used as a base for inspecting parts.
tangent In a right triangle, the ratio of the length of the side opposite the angle divided by the adjacent side.
transversal line A line that intersects two or more lines at different points.
trigonometric ratio A ratio that describes a relationship between a side and angle of a right triangle.
vertical angles Two angles that share the same vertex and are positioned directly opposite one another. Vertical angles are formed whenever two lines intersect.