2. Surface Texture Symbols12
Surface Texture Symbols

3. Explain common terms related to surface quality and surface texture symbols.
Identify and interpret the components of surface texture symbols.
Identify lay symbols used in surface texture symbols.

4. Describe the units used by various values within surface texture symbols.
Explain standard practices for applying surface texture symbols on a print.
Identify special designations related to surface quality that may appear on a print.

5. Surface Texture Terms
Surface texture is the overall roughness, waviness, lay, or flaws of a surface

6. Surface Texture Terms
Roughness height examples

7. Surface Texture Symbols
In the past, finished surfaces were identified with finish marks, as shown here
Surface texture symbols are now used instead

8. Surface Texture Symbol
A—Basic surface texture symbol
B—Material removal is required by machining
C—Indicates a minimum amount that must be removed
D—Material removal is prohibited
E—Horizontal bar to help locate parameters and values

9. Surface Texture Values
(a) Average roughness value (in microinches or micrometers)
(b) Optional production method (i.e., MILL or GRIND)
(c) Roughness cutoff or sampling length
(d) Optional lay symbol

10. Surface Texture Values
(e) Minimum material removal (inches or millimeters)
(f) Roughness parameter other than arithmetic average

11. Lay Symbols Lay symbols are not required
If used, there are seven options

12. Lay Symbols

13. Applying Surface Texture Symbols
Surface texture symbols can be attached to:
Surface “edge views”
Extension lines
Leader line shoulders
Placed in a note

15. What is the difference between surface texture and surface roughness?
Surface texture is the overall roughness, waviness, lay, or flaws of a surface, while surface roughness is the fine irregularities in the surface texture.

16. Which microinch value appearing in a surface texture symbol indicates the finer finish, 8 or 1000?

17. When the  symbol appears in the surface texture symbol, what does it indicate?
It is a lay symbol that means the lay is perpendicular to the edge view line to which the texture symbol is applied.

18. If the value .06 appears under the horizontal bar in a surface texture symbol, what does this mean?
It specifies a roughness cutoff, or sampling length, of .06 inches.

19. List three methods that may be used to place surface texture symbols on a drawing in order to reduce clutter in a view.
Place the symbol on an extension line or leader line to the edge view of the feature or include the symbol in a note.

20. What is surface mismatch?
An uneven blend on a machined surface resulting from multiple passes of a cutter.