The choice of scale in which the drawing, an important task of each design engineer will be executed. At implementation of drawings of small details or assembly units the natural scale 1:1 at which the drawing of a detail is carried out with sizes of a real object is preferable. Often apply scales of increase or reduction to convenience of reading of the drawing.
1. Attentively study the main inscription of the drawing. Scale has to be specified in the right bottom corner of the main inscription in the corresponding column. In mechanical engineering, instrument making increase scales, for example 2:1, 4:1, etc. are often applied. It is necessary in order that drawings of small details with all put sizes, cuts and sections, could be read with ease the engineer, the master or the worker.
2. On construction plans reduction scales, for example 1:200, 1:400 are used. Often the designer is obliged to apply certain scales to drawings of certain types of buildings or buildings. Scale also has to be specified in the main inscription or in the field of the drawing.
3. If you cannot find scale on the drawing, try to define it independently. For this purpose you need to know what object is represented on the drawing and its overall dimensions. If on the drawing the sizes are not put down, but near at hand you have a detail, it is possible to measure it by means of a caliper, a ruler or a roulette.
4. Find that type of a detail on which overall dimensions are put on the drawing. Apply a ruler or a roulette to the dimensional line of one of overall dimensions and measure its length. On the drawing it looks as a piece with shooters on the ends and numerical value of the size in the middle.
5. Compare the received result to numerical value of the size. For this purpose divide result into numerical value. For example, you received value of 16 mm, and on the dimensional line 8 are written. Having divided values, you receive number 2, it also will be the increase scale as the measured piece appeared more value of the size twice.
6. If you cannot find scale on the construction plan, try to find out the sizes of the designed or already available building. Approximately it is possible to determine the actual sizes of the building, having estimated the number of floors in it, height of ceilings, etc. Then also measure height of the building represented on the drawing, and compare values. Surely consider that the sizes on drawings are affixed in millimeters.