Product Directory    Socket Wrenches

 
ANSI-B18.2.1, Appendix V          
WRENCH OPENINGS FOR SQUARE AND HEX BOLTS AND SCREWS
Nominal Size of Wrench also Basic (Maximum) width Across Flats of Bolt and Screw Heads Allowance Between Bolt or Screw Head and Jaws of Wrench Wrench Openings Square Bolts Heavy Hex Bolt
Hex Bolt Heavy Hex Screw
Hex Cap Screw Heavy Hex Structural Bolt
Lag Screw
Min Tol Max Nominal Product Sizes
  1/8 0.1250 0.002 0.127 0.005 0.132    
  5/32 0.1562 0.002 0.158 0.005 0.163    
  3/16 0.1875 0.002 0.190 0.005 0.195    
  7/32 0.2188 0.002 0.220 0.005 0.225    
  1/4 0.2500 0.002 0.252 0.005 0.257    
  9/32 0.2813 0.002 0.283 0.005 0.288 No. 10  
               
  5/16 0.3125 0.003 0.316 0.006 0.322    
 11/32 0.3438 0.003 0.347 0.006 0.353    
  3/8 0.3750 0.003 0.378 0.006 0.384   1/4  
  7/16 0.4375 0.003 0.440 0.006 0.446   1/4  
               
  1/2 0.5000 0.004 0.504 0.006 0.510   5/16  
  9/16 0.5625 0.004 0.566 0.007 0.573   3/8  
  5/8 0.6250 0.004 0.629 0.007 0.636   7/16  
 11/16 0.6875 0.004 0.692 0.007 0.699    
               
  3/4 0.7500 0.005 0.755 0.008 0.763   1/2  
 13/16 0.8125 0.005 0.818 0.008 0.826   9/16  
  7/8 0.8750 0.005 0.880 0.008 0.888     1/2
 15/16 0.9375 0.006 0.944 0.009 0.953   5/8  
               
1      1.0000 0.006 1.006 0.009 1.015    
1  1/16 1.0625 0.006 1.068 0.009 1.077     5/8
1  1/8 1.1250 0.007 1.132 0.010 1.142   3/4  
1  1/4 1.2500 0.007 1.257 0.010 1.267     3/4
               
1  5/16 1.3125 0.008 1.320 0.011 1.331   7/8  
1  3/8 1.3750 0.008 1.383 0.011 1.394    
1  7/16 1.4375 0.008 1.446 0.011 1.457     7/8
               
1  1/2 1.5000 0.008 1.508 0.012 1.520 1       
1  5/8 1.6250 0.009 1.634 0.012 1.646   1     
1 11/16 1.6875 0.009 1.696 0.012 1.708 1  1/8  
1 13/16 1.8125 0.010 1.822 0.013 1.835   1  1/8
1  7/8 1.8750 0.010 1.885 0.013 1.898 1  1/4  
               
2      2.0000 0.011 2.011 0.014 2.025   1  1/4
2  1/16 2.0625 0.011 2.074 0.014 2.088 1  3/8  
2  3/16 2.1875 0.012 2.200 0.015 2.215   1  3/8
2  1/4 2.2500 0.012 2.262 0.015 2.277 1  1/2  
2  3/8 2.3750 0.013 2.388 0.016 2.404   1  1/2
2  7/16 2.4375 0.013 2.450 0.016 2.466 1  5/8  
               
2  9/16 2.5625 0.014 2.576 0.017 2.593   1  5/8
2  5/8 2.6250 0.014 2.639 0.017 2.656 1  3/4  
2  3/4 2.7500 0.014 2.766 0.017 2.783   1  3/4
2 13/16 2.8125 0.015 2.827 0.018 2.845 1  7/8  
2 15/16 2.9375 0.016 2.954 0.019 2.973   1  7/8
               
3      3.0000 0.016 3.016 0.019 3.034 2       
3  1/8 3.1250 0.017 3.142 0.020 3.162   2     
3  3/8 3.3750 0.018 3.393 0.021 3.414 2  1/4  
3  1/2 3.5000 0.019 3.518 0.022 3.540   2  1/4
3  3/4 3.7500 0.020 3.770 0.023 3.793 2  1/2  
3  7/8 3.8750 0.020 3.895 0.023 3.918   2  1/2
               
4  1/8 4.1250 0.022 4.147 0.025 4.172 2  3/4  
4  1/4 4.2500 0.022 4.272 0.025 4.297   2  3/4
4  1/2 4.5000 0.024 4.524 0.026 4.550 3       
4  5/8 4.6250 0.024 4.649 0.027 4.676   3     
4  7/8 4.8750 0.025 4.900 0.028 4.928 3  1/4  
               
5      5.0000 0.026 5.026 0.029 5.055    
5  1/4 5.2500 0.027 5.277 0.030 5.307 3  1/2  
5  3/8 5.3750 0.028 5.403 0.031 5.434    
5  5/8 5.6250 0.029 5.654 0.032 5.686 3  3/4  
5  3/4 5.7500 0.030 5.780 0.033 5.813    
               
6      6.0000 0.031 6.031 0.034 6.065 4       
6  1/8 6.1250 0.032 6.157 0.035 6.192    

 

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