When using this method, the first value should be the limit first arrived at when machining. ![]() In this case, only the maximum and minimum values allowed for the dimension are shown, stacked vertically, instead of including any separate tolerance values. The target size is 0.500" and a part measuring anywhere between 0.499" and 0.500" would pass inspection, but notice that the tolerance is unilateral since deviation is allowed only in the negative direction in this cas Unilateral tolerances _ notation is an alternative method of showing the tolerance range of a dimension. In the Open Content License, v1._ allow deviation in one direction only. Material may be distributed only subject to the terms and conditions set forth With the exception of the caliper simulation, all text and Hwang, Department of Physics, National Taiwan Normal Univ., and is used by The Java applet to simulate the vernier caliper was written by Fu-Kwan Values, for which we would have to estimate the value. Note that there is a small difference between the simulation and a realĬaliper: in the simulation the distance between the jaws is always an even When you click on the Show button the distance between "grab" the jaw of the caliper with the left button of the mouse and move it to There is also a piece of metal sticking out from the right side of the caliper, which is a depth gauge.Ĭalipers commonly use a vernier scale. In the above photograph, you can see that on the top of the caliper are two "prongs" which can be used to measure an interior dimension. The Object is almost exactly 75 mm (2.95 in) The Object will be placedīetween the "jaws" of the caliper. AĬaliper measures a length, and in the following figure we show a caliper being Now we shall use a simulation of a Vernier Caliper. This "reading error" of ± 0.02 is probably the correctĮrror of precision to specify for all measurements done with this Might report this reading as 756.73 ± 0.02. Somewhat below the corresponding line of the scale. In fact, the 7 line on the vernier appears to be a little bitĪbove the corresponding line on the scale. The scale, the 7 line matches fairly closely. Looking for divisions on the vernier that match a division on The pointer points to a value that is obviously greater than 756.5 and also Here is a final example, with the vernier at yet another position. This means that ourįirst guess was correct: the reading is 756.5. Up exactly with one of the lines on the scale, the 5 line. If you look you will see that only one line on the vernier lines Here the "pointer" lines up at approximately 756.5 on the The pointer, the line marked 0, may not line up exactly with one of the lines ![]() If we do another reading with the vernier at a different position, On the vernier are 90% of the distance between the divisions on the Line on the vernier lines up at 756 on the scale, but the 10 line on the ![]() If you look closely you will see that the distance between theĭivisions on the vernier are not the same as the divisions on the scale. Measured position is almost exactly 756 in whatever units the scale is ![]() The "pointer" is the line on the vernier labelled "0". This could be part of a barometer which reads atmospheric pressure. In theįigure to the right, the Vernier moves up and down to measure a position on the A Vernier allows a precise reading of some value.
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