Dial caliper

A dial caliper (see Fig. 2.9) is easier to read than a vernier caliper, but this ease comes at a price. An acceptable vernier caliper can be purchased for 30 - 50, and it can be found with metric and English measurements on the same tool. A good-quality dial caliper may cost between 75 and 150, and it shows only metric or English measurements. On the dial caliper, the 10th place is read on the numbers of the dial itself, and the 100th place is read on the lines between the numbers. 

The pattern, oriented vertically on the target plane, was sharp and bright so that at least 10 orders of diffraction could be seen with minimal darkening of the room. The size of the pattern was such that visual examination permitted 4 to 6 orders of minima to be pricked into index-card stock held against the target plane and conveniently measured with 10 cm dial calipers readable to 0.001 cm. 

FIGURE 16-33 (a) A dial caliper and (b) a micrometer are precision measuring instruments. 

The dial caliper can accurately measure objects to thousandths of an inch. It takes practice to read this instrument. This is a versatile measuring device because it can measure either outside or inside dimensions. The long jaws at the top measure the outside dimension of an object. On the opposite side are two shorter jaws that are designed to measure inside a hole or a piece of tubing. 

Dial calipers (Fig. 6.7) are a form of vernier caliper where readings of 1mm steps are taken from the vernier beam and subdivisions of this are read direct on a dial graduated in 0.02 mm divisions. 

Hydraulic arbor lockup nuts have become a standard in the industry. Unfortunately, research on these nuts and their effect on tooling has been sparse. A test that we have done and recommend for every application where hydraulic nuts are used is as follows. After confirming arbor and slitter-head tolerance specifications by making a setup that is clean (shimless and without stripper rings), set the overlap to zero, and, with a dial caliper, check and record each male and female size from the outside face of the knives. Be sure to remove by carefully stoning any grinding burr from the knife faces. 

A tape measure can be used to measure distances from about 20 cm up to several meters. Dial calipers are useful for closely measuring extruded products, dimensions of the extruder screws, extrusion tooling, etc. A stopwatch is an indispensable tool for measuring screw speed, line speed, blender calibration, etc. A scale can be used to measure the output of an extruder. A small voltmeter is very useful in making sure that voltage and resistance levels of various components are at their required values. A millivolt source can be used for verifying thermocouple inputs and to check controller response and line continuity. 

Linear Measurement (micrometers, dial calipers, surface plates, optical comparators, scientific rotation)... 

Precision measurement is an important part of any maintenance procedure. Without micrometers, telescopic gauges, dial calipers, edge finders, and other precision measuring tools, the job cannot be done correctly. The areas covered in this chapter are ... 

Another tool that is widely used is the dial caliper. The dial caliper can take inside, outside, and depth measurements. The only drawback is that it is not as accurate as the micrometer (measurements to within. 001"). See Figure 20.9. 

A dial caliper is similar to an inside and outside micrometer, but it can take both Inside and outside measurements with just one device. A dial caliper has two measurement scales the scale on the long flat body is graduated in. 100 of an inch, and the round dial is graduated in. 001 of an inch. See Figures 20.13 and 20.14. 

Using the same pillow-block bearings and drill bits that were used in the previous exercises, measure the objects and compare the measurement that you get with the dial caliper to that of the micrometers. If you did not write down your answers from the previous exercise, then repeat the other exercises along with this one. 

The parts were measured with a level dial caliper in order to quantify the warpage. It should be noted that when comparing the warpage of filled parts to non-filled parts the value itself cannot be compared directly. The purpose of this study is to illustrate the different types of warpage (saddle vs. bowl shaped) of filled and unfilled materials at different fill rates. A comparison of the average dimensions of each group of fiU rates for each material separately is used to compare data. 

Therefore, the measurement procedure for the unfilled parts was different than for the filled parts. The unfilled, bowl shaped parts were measured using a level dial caliper and measurements were taken where the warpage was minimal around the perimeter and where it was maximum at the center. These measurements can be seen in Table 1 along with the difference between the two measurements and the average difference for all three fill rates. 

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