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ASME B18.6.3 Slotted Flat Countersunk Head Machine Screws

ASME B18.6.3 Slotted Flat Countersunk Head Machine Screws Standard is intended to cover the complete general and dimensional data for the various types of slotted and recessed head machine screws, tapping screws, and metallic drive screws recognized as American National Standard. Also included are appendices that provide specifications and instructions for the protrusion gaging of flat countersunk head screws; across-corners gaging of hex head screws; penetration gaging and wobble gaging of recessed head screws; approximate hole size for tapping screws; wrench openings for hex and square products; thread dimensions for the No. 0000, No. 000, and No. 00 sizes; means for determining effective grip lengths on screws; documentation for screw types and head types relegated to not-recommended or limited-usage status; and formulas on which dimensional data are based. It shall be understood, however, that where questions arise concerning acceptance of product, the dimensions in the tables shall govern over recalculation by formula.
The inclusion of dimensional data in ASME B18.6.3 Standard is not intended to imply that all of the products described are stock production sizes. Consumers should consult with suppliers concerning the availability of products.

ASME B18.6.3 Slotted Flat Countersunk Head Machine Screws

ASME B18.6.3 Slotted Flat Countersunk Head Machine Screws Dimensions (mm)

Nominal Size Machine Screw Length, L These Lengths or Shorter Are Undercut Head Diameter, A Head Height, H, Ref. Slot Width, J Slot Depth, T Protrusion Above Gaging Diameter, F Gaging Diameter, G
Type A & AB Tapping Screws Other Types of Tapping Screws Max. Min. Max. Min. Max. Min. Max. Min.
#0000 0.533 - - - 1.016 0.889 0.279 0.203 0.102 0.178 0.076 - - -
#000 0.864 - - - 1.524 1.397 0.406 0.279 0.178 0.229 0.127 - - -
#00 1.194 - - - 2.210 2.032 0.711 0.432 0.254 0.356 0.229 - - -
#0 1.524 3.175 4.763 3.175 2.845 2.438 0.889 0.584 0.406 0.381 0.254 0.660 0.406 1.981
#1 1.854 3.175 4.763 2.381 3.480 3.048 1.092 0.660 0.483 0.483 0.305 0.711 0.406 2.565
#2 2.184 3.175 4.763 4.763 4.115 3.658 1.295 0.787 0.584 0.584 0.381 0.737 0.432 3.150
#3 2.515 3.175 5.556 5.556 4.750 4.242 1.499 0.889 0.686 0.686 0.432 0.787 0.457 3.759
#4 2.845 4.763 6.350 6.350 5.385 4.851 1.702 0.991 0.787 0.762 0.508 0.813 0.483 4.369
#5 3.175 4.763 6.350 6.350 6.020 5.461 1.905 1.092 0.889 0.864 0.559 0.864 0.508 4.978
#6 3.505 4.763 7.938 7.938 6.655 6.045 2.108 1.219 0.991 0.965 0.610 0.914 0.533 5.588
#7 3.835 - 9.525 9.525 7.290 6.655 2.311 1.219 0.991 1.041 0.686 0.940 0.559 6.172
#8 4.166 6.350 11.113 11.113 7.925 7.239 2.540 1.372 1.143 1.143 0.737 0.991 0.584 6.782
#10 4.826 7.938 12.700 12.700 9.195 8.458 2.946 1.524 1.270 1.346 0.864 1.067 0.635 7.950
#12 5.486 9.525 14.288 14.288 10.465 9.652 3.353 1.702 1.422 1.524 0.991 1.143 0.686 9.195
#14 6.147 - 15.875 - 11.735 10.846 3.759 1.905 1.626 1.727 1.118 1.245 0.737 10.414
1/4 6.350 11.113 15.875 15.875 12.116 11.227 3.886 1.905 1.626 1.778 1.168 1.270 0.737 10.770
#16 6.807 - 19.050 - 13.005 12.065 4.166 1.905 1.626 1.905 1.245 1.321 0.787 11.608
#18 7.468 - 20.638 - 14.249 13.259 4.572 2.134 1.829 2.108 1.372 1.397 0.838 12.827
5/16 7.938 12.700 20.638 15.875 15.164 14.122 4.851 2.134 1.829 2.235 1.473 1.448 0.864 13.691
#20 8.128 - 20.638 - 15.519 14.453 4.978 2.134 1.829 2.286 1.499 1.473 0.889 14.046
#24 9.449 - 25.400 - 18.059 16.866 5.791 2.388 2.057 2.667 1.753 1.651 0.991 16.459
3/8 9.525 14.288 - 15.875 18.212 17.018 5.842 2.388 2.057 2.692 1.778 1.651 0.991 16.586
7/16 11.113 15.875 - 19.050 19.304 18.161 5.664 2.388 2.057 2.616 1.676 1.854 1.118 17.526
1/2 12.700 19.050 - 19.050 20.701 19.431 5.664 2.692 2.311 2.616 1.651 2.057 1.245 18.771
9/16 14.288 - - - 23.673 22.301 6.604 2.997 2.591 3.048 1.956 2.261 1.346 21.615
5/8 15.875 - - - 26.670 25.146 7.569 3.378 2.946 3.480 2.235 2.464 1.473 24.435
3/4 19.050 - - - 32.639 30.861 9.449 3.785 3.327 4.343 2.819 2.845 1.702 30.124

ASME B18.6.3 Slotted Flat Countersunk Head Machine Screws Dimensions (Inch)

Nominal Size Machine Screw Length, L These Lengths or Shorter Are Undercut Head Diameter, A Head Height, H, Ref. Slot Width, J Slot Depth, T Protrusion Above Gaging Diameter, F Gaging Diameter, G
Type A & AB Tapping Screws Other Types of Tapping Screws Max. Min. Max. Min. Max. Min. Max. Min.
#0000 0.0210 - - - 0.040 0.035 0.011 0.008 0.004 0.007 0.003 - - -
#000 0.0340 - - - 0.060 0.055 0.016 0.011 0.007 0.009 0.005 - - -
#00 0.0470 - - - 0.087 0.080 0.028 0.017 0.010 0.014 0.009 - - -
#0 0.0600 1/8 3/16 1/8 0.112 0.096 0.035 0.023 0.016 0.015 0.010 0.026 0.016 0.078
#1 0.0730 1/8 3/16 5/32 0.137 0.120 0.043 0.026 0.019 0.019 0.012 0.028 0.016 0.101
#2 0.0860 1/8 3/16 3/16 0.162 0.144 0.051 0.031 0.023 0.023 0.015 0.029 0.017 0.124
#3 0.0990 1/8 7/32 7/32 0.187 0.167 0.059 0.035 0.027 0.027 0.017 0.031 0.018 0.148
#4 0.1120 3/16 1/4 1/4 0.212 0.191 0.067 0.039 0.031 0.030 0.020 0.032 0.019 0.172
#5 0.1250 3/16 1/4 1/4 0.237 0.215 0.075 0.043 0.035 0.034 0.022 0.034 0.020 0.196
#6 0.1380 3/16 5/16 5/16 0.262 0.238 0.083 0.048 0.039 0.038 0.024 0.036 0.021 0.220
#7 0.1510 - 3/8 3/8 0.287 0.262 0.091 0.048 0.039 0.041 0.027 0.037 0.022 0.243
#8 0.1640 1/4 7/16 7/16 0.312 0.285 0.100 0.054 0.045 0.045 0.029 0.039 0.023 0.267
#10 0.1900 5/16 1/2 1/2 0.362 0.333 0.116 0.060 0.050 0.053 0.034 0.042 0.025 0.313
#12 0.2160 3/8 9/16 9/16 0.412 0.380 0.132 0.067 0.056 0.060 0.039 0.045 0.027 0.362
#14 0.2420 - 5/8 - 0.462 0.427 0.148 0.075 0.064 0.068 0.044 0.049 0.029 0.410
1/4 0.2500 7/16 5/8 5/8 0.477 0.442 0.153 0.075 0.064 0.070 0.046 0.050 0.029 0.424
#16 0.2680 - 3/4 - 0.512 0.475 0.164 0.075 0.064 0.075 0.049 0.052 0.031 0.457
#18 0.2940 - 13/16 - 0.561 0.522 0.180 0.084 0.072 0.083 0.054 0.055 0.033 0.505
5/16 0.3125 1/2 13/16 5/8 0.597 0.556 0.191 0.084 0.072 0.088 0.058 0.057 0.034 0.539
#20 0.3200 - 13/16 - 0.611 0.569 0.196 0.084 0.072 0.090 0.059 0.058 0.035 0.553
#24 0.3720 - 1 - 0.711 0.664 0.228 0.094 0.081 0.105 0.069 0.065 0.039 0.648
3/8 0.3750 9/16 - 5/8 0.717 0.670 0.230 0.094 0.081 0.106 0.070 0.065 0.039 0.653
7/16 0.4375 5/8 - 3/4 0.760 0.715 0.223 0.094 0.081 0.103 0.066 0.073 0.044 0.690
1/2 0.5000 3/4 - 3/4 0.815 0.765 0.223 0.106 0.091 0.103 0.065 0.081 0.049 0.739
9/16 0.5625 - - - 0.932 0.878 0.260 0.118 0.102 0.120 0.077 0.089 0.053 0.851
5/8 0.6250 - - - 1.050 0.990 0.298 0.133 0.116 0.137 0.088 0.097 0.058 0.962
3/4 0.7500 - - - 1.285 1.215 0.372 0.149 0.131 0.171 0.111 0.112 0.067 1.186

ASME Material Specifications

ASTM A193/A193M Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High Temperature or High Pressure Service and Other Special Purpose Applications
ASTM A307 Standard Specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength
ASTM A449 Standard Specification for Hex Cap Screws, Bolts and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength
ASTM A453/A453M Standard Specification for Bolting, Stud Bolts, Screws, Nuts
ASTM A354 Standard Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners
ASTM A320 Standard Specification for Alloy-Steel and Stainless Steel Bolting for Low-Temperature Service
ASTM A1082/A1082M Standard Specification for Bolting, Stud Bolts, Screws, Nuts
ASTM A1014/A1014M Standard Specification for UNS N07718 Bolting, Stud Bolts, Screws, Nuts
ASTM F468 Standard Specification for Nonferrous Bolts, Hex Cap Screws, and Studs
ASTM F593 Standard Specification for Stainless Steel Bolts, Hex Cap Screws, and Studs
ASTM F901 Aluminium Transmission Tower Bolts
ASTM F738 Stud Bolts, Screws
ASTM F1554 Anchor Bolts, Anchor Rods
ASTM F2281 Bolting, Stud Bolts, Screws, Hex Cap Screws, Threaded Rods
ASTM F3125 Heavy Hex Bolts, Screws, Studs

ISO Material Specifications

ISO 898-1 Bolting Fasteners, Bolting Stud Bolts, Screws
ISO 3506-1 Bolting, Stud Bolts, Screws, Nuts
ISO 3506-5 Bolting, Stud Bolts, Screws, Nuts

EN Material Specifications

EN 10269 Bolting Fasteners, Bolting Stud Bolts, Screws, Nuts, Washers