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Go and No Go Gages Hexagon Sockets

Dimensions of Go and No go Gages for Hexagon Sockets per. ASME B18.3

Hexagon sockets in screws shall allow the GO member of the gage to enter freely to the minimum key engagement depths specified in the dimensional tables for the respective screw types.

For hexagon sockets that are not chamfered, the NO GO gage member shall not enter any of the three across flat dimensions of the socket for nominal socket sizes of 1⁄8 in. and larger, and the hexagonal NO GO gage member shall not enter the socket for nominal socket sizes smaller than 1⁄8 in.

For chamfered hexagon sockets, the NO GO gage member shall be permitted to enter only to a depth equivalent to 10% of the nominal socket size for nominal socket sizes up to and including 1⁄16 in., and to 7.5% of the nominal socket sizes for larger sockets.

Dimension units in inches.

Related:

Socket Head Cap Head Screws Size Table

Dimensions of Go and No go Gages for Hexagon Sockets per. ASME B18.3

Nom.
Socket
Size
Go Gage
Across Flats
A
Go Gage
AcrossWidth
Corners
B
Min.
GO
Gage
Length
C
Minimum
Usable
Gage
Length
D
No Go
Gage
Width
E
No Go
Gage
Thichness
F
No Go
Gage
Width
Across
Corners
G
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Min.
-
 
0.028
0.0281
0.0280
0.0316
0.0314
0.062
0.062
0.0285
0.0284
-
-
0.0308
0.0303
-
0.035
0.0351
0.0350
0.0395
0.0393
0.093
0.093
0.0355
0.0354
-
-
0.0386
0.0381
-
0.050
0.0501
0.0500
0.0562
0.0560
0.187
0.187
0.0510
0.0509
-
-
0.0550
0.0545
1⁄16
0.062
0.0626
0.0625
0.0703
0.0701
0.187
0.187
0.0635
0.0634
-
-
0.0688
0.0683
5⁄64
0.078
0.0782
0.0781
0.0882
0.0880
0.187
0.187
0.0791
0.0790
-
-
0.0862
0.0857
3⁄32
0.094
0.0939
0.0937
0.1060
0.1058
0.250
0.250
0.0952
0.0950
-
-
0.1036
0.1031
7⁄64
0.109
0.1096
0.1094
0.1240
0.1238
0.250
0.250
0.1111
0.1109
-
-
0.1212
0.1207
1⁄8
0.125
0.1252
0.1250
0.1420
0.1418
0.250
0.250
0.1270
0.1268
0.057
0.055
-
-
9⁄64
0.141
0.1408
0.1406
0.1595
0.1593
0.250
0.250
0.1426
0.1424
0.064
0.062
-
-
5⁄32
0.156
0.1564
0.1562
0.1776
0.1774
0.250
0.250
0.1587
0.1585
0.071
0.069
-
-
3⁄16
0.188
0.1877
0.1875
0.2137
0.2135
0.250
0.375
0.1900
0.1898
0.088
0.086
-
-
7⁄32
0.219
0.2189
0.2187
0.2492
0.2490
0.250
0.437
0.2217
0.2215
0.102
0.100
-
-
1⁄4
0.250
0.2502
0.2500
0.2848
0.2845
0.312
0.500
0.2530
0.2528
0.117
0.115
-
-
5⁄16
0.312
0.3127
0.3125
0.3573
0.3570
0.312
0.625
0.3160
0.3158
0.150
0.148
-
-
3⁄8
0.375
0.3752
0.3750
0.4288
0.4285
0.500
0.750
0.3790
0.3788
0.180
0.178
-
-
7⁄16
0.438
0.4377
0.4375
0.5008
0.5005
0.500
0.875
0.4420
0.4418
0.211
0.209
-
-
1⁄2
0.500
0.5002
0.5000
0.5718
0.5715
0.500
1.000
0.5050
0.5048
0.241
0.239
-
-
9⁄16
0.562
0.5627
0.5625
0.6424
0.6420
0.750
1.125
0.5680
0.5678
0.269
0.267
. . .
. . .
5⁄8
0.625
0.6252
0.6250
0.7150
0.7146
0.750
1.250
0.6310
0.6308
0.302
0.300
. . .
. . .
3⁄4
0.750
0.7502
0.7500
0.8585
0.8580
0.750
1.500
0.7570
0.7568
0.364
0.362
. . .
. . .
7⁄8
0.875
0.8752
0.8750
1.0025
1.0020
0.875
1.750
0.8850
0.8848
0.423
0.421
. . .
. . .
1
1.000
1.0002
1.0000
1.1475
1.1470
1.000
2.000
1.0200
1.0198
0.489
0.487
. . .
. . .

Notes:

  • Gages shall be made from any grade of steel, through hardened and tempered to 60 HRC minimum.
  • The form of hexagonal and spline gage members shall be within the tolerance zone specified. See ASME Y14.5M, Engineering Drawing and Related Documentation Practices, Dimensioning and Tolerancing.
  • The surface roughness on hexagon and spline flats shall be 8 in. (arithmetical average) maximum. See ASME B46.1, Surface Texture.
  • The gage handles shall conform to ASME B47.1, Gage Blanks.