The vernier caliper is one instrument of measurement dopted of one scale and a cursor that slides in itself and it was concebed to take linear dimensions by contact.
The most popular type in the metal-mechanic offices is the one dopted of vernier, but, usually, all kinds alows to take external, internal, depth and rebound meausres.
To comprehend the science of the measurement with caliper, we suggest you to read and to interact with the simulators in the pages:
Some caliper models are four-dimensionals, this means that it can be used in four different ways in the measurement. See some examples of best practices:
evidently, it is necessary to adpat this procedure to each kind of measurement, for example, it is possible to move the caliper before the reading in depht or rebound measures, or to internal or external measures. The first step is to open the instrument a little bit less that the hole to be meausured and the 6th step is to close the instrument before removing it from the hole.
best practices of external measurement with vernier caliper
external measurement -
object very far from scale
Gently, close the caliper and press the faces of the backrests fixed and movable against the paralel faces, or diameter, of the distance you intend to measure, figure 1.
Alow the caliper to align with the object that is beeing measured. This is possible holding them together without tightening.
Place the object close to the main scale, no touch in there, figure 2
best practices of internal measurement with vernier caliper
internal measurement - object very far from cursor
Gently, open the caliper and press the faces of the ears fixed and movable against the paralel faces, or the hole that you intend to measure, figure 3.
Alow the caliper to align with the hole or rip that is beeing measured. this is possible holding them together without tightening.
Place the object the most close possible of the cursor, conterexample figure 4.
depth measurement with vernier caliper
Hold the top of the main scale of the caliper in the surface of the piece, open it and, gently, press the top of the rod of depth against the end of the hole or rip that you intend to measure, figure 5.
Alow that the rod remais in paralel with the hole or rip that is beeing measured. This is possible holding them together without tightening.
best practices of internal measurement with vernier caliper - drill hole
measure of drill hole - rod measuring part of the cone
Take care to don't lose the refference, use the side of the rod of depth with no slot, figure 6.
If you use the side with slot, the top of the rod will go until take place in the cone of the drill point, adding a few more tenths of millimeter to the measure, figure 7.
best practices of internal measurement with vernier caliper- drill hole
measure of blind hole -
rod measuring burr
To measure the depth of one blind hole, use the side of the rod with the burr, figure 8. This practice avoid round measurement of the botton.
measurement of rebounds with vernier caliper
Some caliper companies have added one caractheristic very interesting, that alows the measurement of rebounds. The top of the cursor and of the main scale are coplanar. This way, it can be used much greater accuracy than that obtained when using the depth rod, figure 10.