SPI – VDI3400 surface roughness conversion | Minimum Drafting Angles

VDI 3400

ISO, VDI,ASA

ISO/TC 213

SPI

Polishing Grade

Drafting Angles

Charmilles

Ra=CLA=AA

Rz

RMS

PA

PC

ABS

CH

µm

µinch

µm

Tipo

µm

µinch

0.025

1

N1

A1

0.022-0.043

0.5-1

Grade #3 Diamond

0. 05

2

N2

A2

-0.08

1-2

Grade #6 Diamond

0

0. l

4

N3

A3

-0.3

2-7

Grade #15 Diamond

1

0. 11

4.48

2

0. 12

5.04

3

0. 14

5.6

4

0. 16

6.4

5

0. 18

7.2

6

0. 2

8

Bl

0.3-0.324

7-9. 75

600 Grit paper

7

0. 22

0. 25

8.8

10

N4

B2

-0. 422

9. 75-12

400 Grit paper

8

9

0. 28

0. 32

11.2

12.8

B3

-0.52

Dez-15

320 Grit paper

10

11

0. 35

14

16

l. 5

Cl

0.52-0.65

15-20.5

600 Stone

12

0.4

N5

0

1

0.5

13

0. 45

18

20

C2

-0.89

20.5-26

400 Stone

14

0. 5

15

0. 56

22.4

25.4

2.4

0.5

1

0.5

16

0.63

C3

-1.125

26-32

320 Stone

17

0.7

28

32

18

0.8

N6

Dl

1. 125-1.385

26-32

Dry Blast Glass Bead

0.5

1

0.5

19

0.9

36

40

20

1

D2

32-

Dry Blast # 240 Oxide

21

1.12

44.8

50.4

4. 7

0.5

1

0.5

22

1.26

23

1.4

56

64

24

1.62

6.5

N7

0 .5

1.5

1

25

1.8

72

80

26

2

27

2.2

88

100

10 .5

1

2

1.5

28

2.5

29

2.8

112

128

30

3.2

12.5

N8

D3

Dry Blast # 24 Oxide

1.5

2

2

31

3.5

140

160

32

4

33

4.5

180

17.5

2

3

2.5

34

5

200

224

35

5.6

36

6.3

252

280

24

N9

2.5

4

3

37

7

38

8

320

360

39

9

34

3

5

4

40

10

400

448

41

11.2

42

12.6

504

560

48

N10

4

6

5

43

14

44

16

640

760

45

18

69

5

7

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China -Europe Surface Roughness Conversion Chart

mm)(China-micro.m) 0.025 0.05 0.1 0.2 0.4 0.8 1.6 3.2 6.3 12.5 25 50
(minch)(Europe-micro.inch) 1 2 4 8 16 32 63 125 250 500 1000 2000
N-Grade N1 N2 N3 N4 N5 N6 N7 N8 N9 N10 N11 N12
Finish Ground Finishes Smooth Turned Medium Turned Rough Machined

Chinese-American Surface Roughness Conversion Chart

Chinese Roughness(µm) Ra American Roughness(µm )Ra American Roughness( µinch),Ra
6.3 8.00 320
6.30 250
3.2 5.00 200
4.00 160
3.20 125
1.6 2.50 100
2.00 80
1.60 63
0.8 1.25 50
1.00 40
0.80 32
0.4 0.63 25
0.50 20
0.40 16