The electronic digital calipers with a movable plastic bar can reduce the chance of scratching . The tipical use of them is used to measure the outer edges, inner edges and depth of the objects. Here are the tips for the digital calipers to mesure the outer edges, inner edges and depth of the objects.
Measuring the Outer Edges
Befor measuring the outer edges of the objects, first , you need to look at the vernier calipers carefully. Then look at the bump on the bottom edge and you will see that It is a grip for your thumb. Slide it back towards the tail end of the calipers and the jaws open. If you are measuring the outer edge of an object. That is the head of an ushabti figure, you would open the jaws of the calipers and slide them carefully over the head of the ushabti. Read the sliding scales along either top or bottom or read the dial to see the size of the head. At the same time, you must be sure that your calipers are straight for even a slight angle throws off your measurements.It is extremely important for you to remember this is highly precise work and readings must be taken very, very carefully to assure proper dimension and accurate drawings. You also need to remember that it takes much more time to correct your work and find a mistake than to take the time to do it right for the first time!
Measuring the Inner Edges
Those blade on the top edge of the dial calipers like edges sticking out the top. Those are to take measurements of the inside of holes like on the opening of a jar. Firstly, put them inside the opening and carefully spread them using the thumb grip. They will widen simultaneously as the jaws open. You must be careful when you are taking your reading from the widest diameter (distance across). Please do bear in mind that handmade objects will have variance unlike those made by machines of our time. Thus, you need to take several readings and make notes.
Measuring the Depth
Firstly, you need to look at the tail end of the dial calipers and you will see that little thing sticking out the bottom. As you move the thumb grip, simultaneously as the jaws open and the blades spread, that rod will move out the bottom. That is a depth gauge which you can put into a vessel and measure it's depth. Open the calipers until you hit bottom and take your reading.