The caliper, the instruction for use of which allows for fairly accurate measurements, has a simple design. Using it is also quite simple. With it you can determine the internal and external dimensions of the parts. The master can find out how deep the holes and all kinds of protrusions are.
Diagram of the device calipers.
Features of the use of calipers
The caliper is a high-precision instrument of measurement technology. The data obtained during the measurements will have an accuracy in the range of 0.1-0.01 mm. If you are faced with the need to determine the external and internal dimensions, then you should use the bottom located wide, as well as auxiliary pointed sponges. The latter of the above are also used to mark the surface of parts.
Four kinds of measurement with a caliper.
The depth of the holes and the dimensions of the protrusions can be determined by means of a depth gauge, which acts as an integral part of the tool described. The design of the caliper may be different, for example, vernier, arrow or electronic. The last two options have a second name - the dial and digital calipers, respectively. They all have the same design, and their difference lies only in the type of reading device.
The aforementioned circumstances indicate that the principles of using vernier, arrow or digital types of calipers are exactly the same, but there is a difference, and it consists only in the presentation of information by the device. For this reason, it is advisable to consider an example of one of the tools, for example, nonius.Back to table of contents
Preparation before measurement
Before using the caliper, it must be cleaned of grease and dust particles, paying attention to the surfaces that will be involved in the measurements. Next, the tool is required to analyze the accuracy. If the work is performed by means of a vernier device, it will be easy to do - for this it is only necessary to combine the main (wide) caliper sponges, which are located below. At the same time, the marks at the level “0” of both scales should coincide. At the same time, the 19th mark of the scale should coincide with the 10th - on the nonius. Under these conditions, the device can be considered intact and fully ready for measurement.
The use guide regulates the rules for the analysis of analog and digital calipers as well, and the instrument sponges must also be mated with each other.
In the case of the dial of the hand instrument, the pointer should be on the zero mark.
Whereas on the screen of the electronic device should appear the designation "0".Back to table of contents
Care must be taken when working, as the measuring bases of the jaws of the device have dangerous edges. To determine the external size of the element should be firmly clamped between the main, located below the jaws. The tool must be held in the right hand, four fingers should clasp the barbell, while the thumb should be placed on the frame. The frame should be moved with your thumb, and after reaching the desired step between the jaws that mate with the measured base, it is fixed by means of a clip.
Before counting the final result, you should make sure that the sponges have taken the correct position, there should be no distortions, and when you move the element between them, you should feel the force.Back to table of contents
Determination of internal parameters and depth
Internal parameters are determined by means of pointed cavities, for which they will need to be brought into a conjugate state and positioned in the element being measured. After this auxiliary sponge can be diluted. Before reading the data, it is necessary to analyze the observance of the above conditions.
In order to determine the depth, it will be necessary to place a depth gauge located at the end of the device in the hole. After that, you can begin to push the main jaws until the depth gauge comes into contact with the surface. Once this happens, you can see what the readings are. This technology will also allow to analyze the dimensions of the projections. It is worth considering that not every instrument has a depth gauge.
Stages of measurement:
- preparation of the device, including its cleaning and accuracy analysis;
- setting the device value to zero or the maximum possible for the measurement;
- measurement process;
- read data.
The most difficult to read information from nonius instruments. In order to do this, the device must be held in front of your eyes; if you slightly move the caliper to the side, you will not avoid errors. It does not matter which parameter was analyzed, the reading is performed according to one principle.
The base of the instrument scale has a certain bevel, which is necessary for its effective alignment with the main scale, according to the relative positioning of these graduations, and it is possible to determine the parameters of the element. Initially, it is necessary to estimate the number of whole millimeters, which corresponds to the division value of the main scale located to the left of the zero mark of the device. Then you should determine the number of fractions of a millimeter. The scale is a stroke that coincides with the mark of the main scale. If there are several such strokes, then it is necessary to use the value closest to zero of the nonius.