Related Resources: mechanical-tolerances

Gauge Blocks Tolerances Specifications Table BS 4311

Tolerances, Engineering Design & Limits & Fits

Accuracy Specifications table for Gage Blocks by BS 4311: Part 1: 1993 (UK) standard at 20˚C.

Nominal length
(mm)

Grade K

Grade 0

Tolerance on
length 1 (µinches)

Parallelism
(µinches)

Flatness
(µinches)

Tolerance on
length1 (µinches)

Parallelism
(µinches)

Flatness
(µinches)

over 0

up to 0.4

±5

2

2

±5

4

4

over 10

up to 25

±6

2

2

±6

4

4

over 25

up to 50

±8

3

2

±8

4

4

over 50

up to 75

±10

3

2

±10

5

4

over 75

up to 100

±12

3

2

±12

5

4

 

Nominal length
(mm)

Grade 1

Grade 2

Tolerance on
length1 (µinches)

Parallelism
(µinches)

Flatness
(µinches)

Tolerance on
length1 (µinches)

Parallelism
(µinches)

Flatness
(µinches)

over 0

up to 0.4

±10

6

6

±20

12

10

over 10

up to 25

±12

6

6

±25

12

10

over 25

up to 50

±15

7

6

±30

12

10

over 50

up to 75

±20

7

6

±40

14

10

over 75

up to 100

±25

8

6

±50

14

10

SI Units Table

Nominal length (mm)

Grade K

Grade 0

Tolerance on
length1 (0.01µm)

Parallelism
(0.01µm)

Flatness
(0.01µm)

Tolerance on
length1 (0.01µm)

Parallelism
(0.01µm)

Flatness
(0.01µm)

over 0

up to 10

±12

5

5

±12

10

10

over 10

up to 25

±15

5

5

±15

10

10

over 25

up to 50

±20

6

5

±20

10

10

over 50

up to 75

±25

6

5

±25

12

10

over 75

up to 100

±30

7

5

±30

12

10

 

Nominal length (mm)

Grade 1

Grade 2

Tolerance on
length1 (0.01µm)

Parallelism
(0.01µm)

Flatness
(0.01µm)

Tolerance on
length1 (0.01µm)

Parallelism
(0.01µm)

Flatness
(0.01µm)

over 0

up to 10

±25

16

15

±50

30

25

over 10

up to 25

±30

16

15

±60

30

25

over 25

up to 50

±40

18

15

±80

30

25

over 50

up to 75

±50

18

15

±100

35

25

over 75

up to 100

±60

20

15

±120

35

25

1 At the center point

Related Resources: