![quality measuring instruments pdf quality measuring instruments pdf](https://cdn.automationforum.co/uploads/2018/10/instrumets.png)
Here the distance moved by the spindle per revolution is termed as “pitch.” When we put a wire in between the anvil and spindle, we rotate the spindle till it touches the wire. In the case of the micrometer screw gauge, the least count is the ratio of pitch to the number of divisions on the circular scale. Main scale and vernier scale are displayed on sleeve and thimble respectively. Rotating thimble movement is converted to linear movement of spindle.
![quality measuring instruments pdf quality measuring instruments pdf](https://i1.wp.com/gaugehow.com/wp-content/uploads/2019/03/mitutoyo-lever-dial-gauge-1.png)
Micrometer Screw Gauge: To measure diameter of thin wire or thickness of thin metal sheets with accuracy, micrometer screw gauge is very useful. But due to less cost, manually operated vernier calipers are more popular.Ģ. These reduce the complexity of choosing the coincidence of main scale and vernier scale and calculating the final reading as in manually operated vernier caliper. Nowadays, vernier calipers with digital displays or dial gauges are available. Reading accuracy thus depends on the operator’s skill and eyesight. So when we measure a dimension of an object using a vernier caliper, the formula for final dimension is,įinal Dimension=Main scale reading + (Vernier scale reading x Least count)ĭisadvantage: It is very delicate to choose the vernier scale reading, which is the line on the vernier scale, exactly coinciding to a line on the main scale. It is the ratio of the smallest division on the main scale to the total number of divisions on vernier scale. The term “least count” is used to define the accuracy of a vernier caliper. A manually operated vernier caliper has a main scale (in millimeters or inches) and a sliding vernier scale attached to the movable jaw, as shown in the figure. A screw clamp is provided that can lock the position of the vernier scale, so that the instrument can be moved without disturbing the reading. It is provided with inward jaws and outward jaws to facilitate the measurement. Vernier Caliper: It is an instrument used to measure internal and external dimensions of an object with a great accuracy. Here we will look at the features and use of certain well known precision measuring instruments used for linear measurement.ġ. The special branch of science that deals with such instruments is known as metrology. With a need to make quality products which meet design specified tolerances, a large number of firms, research and development centers, and school and college laboratories use measuring instruments that have high accuracy and precision.
![quality measuring instruments pdf quality measuring instruments pdf](https://www.shaalaa.com/images/university-of-mumbai-be-electrical-measurements-measuring-instruments-semester-3-se-second-year-2010-2011_2:ac69dd17706644c18c3f8877350aa4c1.jpg)
Types of Precision Measuring Instruments Used in Industry