A caliper is a measuring device for finding very accurate measurements of an item. These devices are common in many fields such as mechanical engineering and electronic design. There are three basic forms of this device – outside, inside and in depth – and each has its own uses and methods. Out of these three basic types of tools, there are several types with specific functions for a purpose.
A caliper is a measuring device that consists of two parts that open and close. The opening area can be taken off the item you are measuring and measure itself, allowing non-standard items to be sized quickly and easily. The micrometer version is essentially a very accurate gauge; it measures things on a very narrow scale and often has a built-in readout of the size of the measured object.
Most micrometer calibrators have their reading directly on the instrument handle. This usually consists of lines that are discovered when the cursor is opened. In addition to these lines, there may be a secondary scale that measures the fractional areas between the lines of the primary scale.
There are three basic ways. An open cursor measures the outside of an object, such as the head of a screw. An internal caliper measures an opening, such as a screw hole, from the inside. A depth gauge will measure the depth of an opening from bottom to top. Outside of these three basic styles, many tasks have their own calipers, including those for measuring threads on a screw and aligning materials inside a milling machine.
There are several methods for making a caliper, but the end result almost always consists of the same collection of parts. The frame contains the handle and upper jaw. The anvil sits in the upper jaw of the caliper and provides a flat, solid surface for the material to rest on. The spindle is the screw that moves up and down the other side of the anvil – it performs the actual measurement. The sleeve is on the bottom of the shaft and has the actual size reading of the caliper opening.
The gauge measurement reading on the sleeve is based on the relative position of the spindle. The spindle is on a screw that allows it to move up and down. As the spindle moves, the rotating screw creates a mechanical change in the spindle. The spindle separates as the screw retracts and condenses as the screw moves out. This means that the spindle always shows the aperture size using its own printed scale.