Vol.15 HOW TO DRAW AND READ DRAWINGS

When working on machining, you always have to use the drawings.
Proper viewing and drawing of drawings is important for conveying information accurately.
This time, we summarized how to draw and read the drawings.

DESCRIPTION AND NAMES OF THE DRAWING LINES

◆ There are the following four types of lines depending on the shape.

Solid Line		Continuous line
Dotted line		The line where a short line is repeated in turn
Chain line		The line where a line of the length of two kinds of length is repeated in turn
Chain double-dashed line		The line where a line of the length of two kinds of length is repeated in turn, such as long, short, short, long, short, short

◆ There are 3 kinds of line thickness.

Thin line
Thick line
Extra thick line

In the same drawing, make the line thickness uniform for each line type.

The ratio of the thickness of the thin line, thick line, and extra-thick line is 1: 2: 4.

THE USERS OF LINE

Use different types of lines depending on the purpose.
The main uses according to the type of line are as follows.

Line description	Name by use	The Uses of Line
Thick solid line	Outline	It is used for represent the shape of the visible part of the object.
Thin solid line	Dimension line Extension line Leader line	It is used for writing dimensions. It is used to draw from a figure to fill in dimensions. It is used for drawing out descriptions and symbols.
Thin dashed line	Hidden outline	It is used for represent the shape of the invisible part of the object.
Thick dashed line	Hidden outline
Thin chain line	Center line Reference line Pitch line	It is used for represent the center of the figure. In particular, it is used to clearly indicate the basis of position determination. A reference line that takes the pitch of repeated figures.
Thin Chain doubledashed line	Imaginary line	It is used to display information that is not actually there for reference.
Thin wave line	Break line	A line representing the boundary when a part of an object is temporarily removed.
Thin chain line with the part which changes of direction	Cutting line	When drawing a sectional view, it is used to show the cutting position in the corresponding figure.
Thin solid line with Draw regularly	Hatching	It is used to distinguish a specific part of a figure from other parts. For example, the cut end of a sectional view is shown.

TRIGONOMETRY

In general, mechanical drawings are drawn by trigonometry.

Location of each drawing by trigonometry

Correct placement drawn with trigonometry

A :Front view
B :Plan view
C :Left-side view
D :Right-side view
E :Bottom view
F :Back side view

Based on the front view View from right side draws on the right View from left side draws on the left View from the top draws above View from the bottom draws below This is the basic!

SYMBOL FOR DIMENSIONING USED IN DRAWING

In drafting, use a dimension symbol to clarify the meaning of the dimension by adding it to the numerical value representing the dimension.
The main dimension auxiliary symbols are as follows.

Description of numetrical value	Symbol	Purpose of use
Diameter		Put it before diameter dimension
Radius		Put it before radius dimension
Diameter of Sphere		Put it before diameter of sphere dimension
Radius of Sphere		Put it before radius of sphere dimension
Sides of Square		Put it before dimension of a side of square
Thickness of material		Put it before thickness of material dimension
45 degs chamfering		Put it before 45 degs chamfering dimension