For accurate angular measurement, a sine bar is used in combination with slip gauge blocks. A sine bar may be used to face locate any work to a certain angle or to measure angles very precisely. High chromium steel that resists corrosion in used to make sine bars, which are then stabilized, precisely honed, and hardened.
These two cylinders’ axes are parallel to one another and to the top surface of the sine bar at an equal distance from each other. Well, in this reading, I’ll be exploring what sine bar is, its application, principles, its diagram, types, & how it works.
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Contents
What Is Sine Bar?
A sine bar is made up of two precision ground cylinders attached at the ends of a hardened, precision ground body. The top of the bar is parallel to a line that passes through the centers of the two rollers, and the distance between the cylinder centers is accurately regulated.
When in operation, the distance between the two rollers forms the hypotenuse of a triangle, and it is selected to be a whole number for convenience in subsequent computations. The top edge of a sine bar will be parallel to a level surface when it is positioned on it.
The top edge of the bar will tilt by the same amount if one roller is elevated by a specified distance—typically using gauge blocks—forming an angle that can be computed using the sine rule.
- The hypotenuse is always the same length—in the instances, it is 100 mm or 10 inches.
- The measurement between one roller’s bottom and the surface of the table yields the height.
- The sine rule, a mathematical trigonometric function, is used to compute the angle.
- Tables that provide the dimensions needed to achieve an angle between 0 and 90 degrees, incremented by one minute, may be found in several engineering and metalworking reference books.
Application Of Sine Bar
- To check for unknown angles on heavy components.
- For checking the angles of taper key.
- Some specially designed sine bars are used to mount the workpiece to perform conical-shaped machining for the workpiece.
- The sine-bar is used to set or determine the workpiece at a given angle.
- For checking the measurement of unknown angles in the workpiece.
- To check the flatness of the surface.
Sine Bar Principles
A spirit level or dial gauge, together with gauge blocks, are used to measure angles with a sine bar. Measuring the horizontal surface on which a spirit level or dial gauge is positioned is the goal of a measurement. For instance, a wedge is set on a horizontal table to determine its angle.
Over the wedge’s inclination, the sine bar is positioned. The sine bar’s upper surface is angled in the same direction as the wedge at this point. The top edge of a sine bar will be parallel to a level surface when it is positioned on it.
The top edge of the bar will tilt by the same amount if one roller is elevated by a specified distance—typically using gauge blocks—forming an angle that can be computed using the sine rule. It is possible to set up any angle ϴ by using the standard length of side AB, and calculating the height of side BC using BC = AB * sin(ϴ).
The top surface is made horizontal using gauge blocks. The ratio of the height of the gauge blocks utilized and the separation between the cylinder centers is the sine of the wedge’s angle of inclination.
- The use of sine bars involves the use of trigonometry.
- Slip gauges, a sine bar, and a surface plate are utilized to precisely construct an angle.
- By using the standard length of side AB and computing the height of side BC using BC = AB * sin(σ), any angle σ may be set up. σ = asin(BC/AB) gives the angle σ.
- A standard sine bar configuration on a surface plate with slip gauge blocks of the necessary height BC to provide the correct angle σ is shown in Figure 1.
Diagram Of Sine Bar
Types Of Sine Bar
The most basic kind is a steel bar that has been lapped, with an exact cylinder attached to each end. The cylinders’ axes are parallel to each other and to the bar’s top surface.
These are the 3 major types of sine bar listed, Compound sine table, Sine table, Sine center
1. Compound Sine Table
Compound sine table is for precise grinding of many angles, sine tables are perfect, high-quality steel that has been hardened and ground to 55 HRC 1 2 HRC is used to make them, the massive workpieces’ compound angles are measured using it, two sine tables are stacked one on top of the other at right angle in this instance.
To achieve the necessary alignment, the tables may be twisted, an angle may be adjusted to precision of 1/5 of a degree.
2. Sine Table
A sine table is a big broad sine bar used to hold workpieces during operations is called a sine table. It usually has a locking mechanism to secure it in place after placement. A bigger kind of sine bar, called a sine plate, is sometimes furnished with a locking mechnism to secure it in position after it has been positioned.
It uses the same concepts as sine bars, producing right triangles to calculate angles, to hold workpieces at precise angles for precision machining and measurement.
3. Sine Center
A sine centers is a unique kind of sine bar are used for conical shapes with male and female components. An angle more than sixty degrees cannot be measured by it a unique kind of sine bar called a sine center is used particularly to calculate the angles of conical objects with both male and female components.
It can measure angles up to 60 degrees and is made to fit these unusual forms, unlike a regular sine bar. When used in combination with slip gauges, it offers accurate measurements of angles.
How Sine Center Works
- To adjust the proper angle, place these gage blocks under the sine device’s gage block roll. If your gadget has a locking mechanism, tighten it before continuing.
- The center distance of the device (C), the desired angle (A), and whether the angle is in degrees, minutes, seconds, or decimal degrees must all be determined before you can set an angle on any kind of sine device, including sine bars, sine plates, and other sine tools.
- After that, enter the data in the relevant fields below.
- Whether the angle is expressed in decimal degrees or degrees-minutes-seconds, the separator should include a decimal point.
- After selecting the ‘Calculate’ option, build a stack of gage blocks (G) to match the size that isgive back.
- When entering the center distance for a 5 inch sine plate, for example, the gage block stack will likewise be in inches because the units of the stack and the center distance will match.
- The top edge of a sine bar will be parallel to a level surface when it is positioned on it.
- The top edge of the bar will tilt by the same amount if one roller is elevated by a specified distance—typically using gauge blocks—
- Forming an angle that can be computed using the sine rule.