Basic Drafting Skills
Alphabet of Lines
003.03 Identify line symbols
Alphabet of Lines-Introduction
o lines and line symbols used on drawings
o drawings are easier to read
o good contrast among different line symbols
o generally two line widths: thick or thin
o all lines are uniform, sharp and black
003.03 identify line symbols
0
13
7.00
3
2
1
10
8
6
A
1.25
15
7
A
4
9
14
HEX BOLT
11
5
1. Phantom
5. Leader
2. Section
6. Hidden
9. Extension
12. Section
3. Hidden
7. Center
10. Break
SECTION A-A
4. Cutting/Viewing
8. Visible/Object
11. Visible/Object
13. Extension
14. Break
15. Dimension
12
Alphabet of Lines
Visible/Object Lines
o used to show edges of an object
o are thick and dark
003.03 identify line symbols
0
13
7.00
1
10
3
2
8
6
A
1.25
15
7
A
4
9
14
HEX BOLT
11
5
SECTION A-A
12
Identify the Number(s) of Object/Visible Line Symbol
Alphabet of Lines
Hidden Lines
o used to show edge that can not be
seen in a plane
o thin and dashed
003.03 identify line symbols
0
13
7.00
1
10
3
2
8
6
A
1.25
15
7
A
4
9
14
HEX BOLT
11
5
SECTION A-A
12
Identify the Number(s) of Hidden Line Symbol
Alphabet of Lines
Center Lines
o used to show centers of round objects
(arc & circles)
o thin, long and short dashes
003.03 identify line symbols
0
13
7.00
1
10
3
2
8
6
A
1.25
15
7
A
4
9
14
HEX BOLT
11
5
SECTION A-A
12
Identify the Number(s) of Center Line Symbol
Alphabet of Lines-Summary
The alphabet of lines are thick and
thin line symbols used on drawings
that form a kind of graphic alphabet.
Each line and line symbol has a
special meaning.
003.03 identify line symbols
0