|
Lab. Master
FED.* GRADE 0-5 |
Webber AA
FED.* GRADE 1 |
Webber A1
FED.* GRADE 2 |
Webber A |
|||||
|
Length of Block (Inches)
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
|
Through 1"
|
±1
|
1
|
±2
|
2
|
+4 –2
|
4
|
+8 –4
|
5
|
|
2"
|
±1
|
1
|
±4
|
2
|
+8 –4
|
4
|
+16 –8
|
5
|
|
3"
|
±1
|
1
|
±5
|
3
|
+10 –5
|
4
|
+20 –10
|
5
|
|
4"
|
±1
|
1
|
±6
|
3
|
+12 –6
|
4
|
+24 –12
|
5
|
|
5"
|
±7
|
3
|
+14 –7
|
4
|
+28 –14
|
5
|
||
|
6"
|
±8
|
3
|
+16 –8
|
4
|
+32 –16
|
5
|
||
|
7"
|
±9
|
3
|
+18 –9
|
4
|
+36 –18
|
5
|
||
|
8"
|
±10
|
3
|
+20 –10
|
4
|
+40 –20
|
5
|
||
|
10"
|
±12
|
4
|
+24 –12
|
5
|
+48 –24
|
6
|
||
|
12"
|
±14
|
4
|
+28 –14
|
5
|
+56 –28
|
6
|
||
|
16"
|
±18
|
4
|
+36 –18
|
5
|
+72 –36
|
6
|
||
|
20"
|
±20
|
4
|
+40 –20
|
5
|
+80 –40
|
6
|
||
|
Surface Finish Equal to Quartz Flat
|
Surface Finish croblox® .1-.3 Steel .3-.5
|
Surface Finish croblox® .3 Steel .6-.8
|
Surface Finish .8
|
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Metric System: Tolerances expressed in microns (0.001 mm)
|
Lab. Master
FED.* GRADE 0-5 |
Webber AA
FED.* GRADE 1 |
Webber A1
FED.* GRADE 2 |
Webber A |
|||||
|
Length of Block (mm)
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
Tolerance (Length)
|
Flatness & Parallelism
|
|
Through 25 mm
|
±.03
|
.03
|
±.05
|
.05
|
±.10 –.05
|
.10
|
±.20 –.10
|
.12
|
|
25-50 mm
|
±.05
|
.03
|
±.10
|
.05
|
±.20 –.10
|
.10
|
±.40 -.20
|
.12
|
|
50-75 mm
|
±.08
|
.03
|
±.13
|
.07
|
±.25 –.12
|
.10
|
±.45-.22
|
.12
|
|
75-100 mm
|
±.10
|
.03
|
±.15
|
.07
|
±.30 –.15
|
.10
|
±.60-.30
|
.12
|
|
125 mm
|
-
|
-
|
±.18
|
.07
|
±.35 –.18
|
.10
|
±.70-.35
|
.12
|
|
150 mm
|
-
|
-
|
±.20
|
.07
|
±.40 –.20
|
.10
|
±.80-.40
|
.12
|
|
175 mm
|
-
|
-
|
±.23
|
.07
|
±.45 –.22
|
.10
|
±.90-.45
|
.12
|
|
200 mm
|
-
|
-
|
±.25
|
.07
|
±.50 –.25
|
.10
|
±1.0-.50.
|
.12
|
|
250 mm
|
-
|
-
|
±.30
|
.10
|
±.60 –.30
|
.12
|
±1.2-.60
|
.15
|
|
300 mm
|
-
|
-
|
±.35
|
.10
|
±.70 –.35
|
.12
|
±1.4-.70
|
.15
|
|
400 mm
|
-
|
-
|
±.45
|
.10
|
±.90 –.45
|
.12
|
±1.8-.90
|
.15
|
|
500 mm
|
-
|
-
|
±.50
|
.10
|
±1.0 –.50
|
.12
|
±2.0-1.0
|
.15
|
|
Surface Finish Equal to Quartz Flat
|
Surface Finish croblox® .003-.008 Steel .008-.012
|
Surface Finish croblox® .008 Steel .015-.020
|
Surface Finish .020
|
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|
*Starrett-Webber Standards of Accuracy are guaranteed to meet those of U.S. Federal Specifications GGG-G-15C, British Standard 4311 (1968) and 888 (1950); German Standard DIN 861 (1959)
|
|
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|
•Grades 0.5 and 1 surpass British Reference Guide
|
|||||
|
•Grades 0.5, 1, and 2 surpass German Grade 0
|
|||||
|
Reference Temperature – 68° F (20° C)
One Inch = 25.4 millimeters |
| Above information provided by The L.S. Starrett Co.® and The LS Starrett Co.® Webber Gage Division |