Hex Head Tap Bolts
![](hexheadtap.gif)
FULLY THREADED HEX TAP BOLTS ASME B18.2.1-1996 |
Nominal
or
Basic
Product
Diameter
|
F |
G |
H |
Width Across Flats |
Width
Across
Corners |
Head Height |
Basic |
Max |
Min |
Max |
Min |
Basic |
Max |
Min |
1/4 |
0.2500 |
7/16 |
0.438 |
0.428 |
0.505 |
0.488 |
5/32 |
0.163 |
0.150 |
5/16 |
0.3125 |
1/2 |
0.500 |
0.489 |
0.577 |
0.557 |
13/64 |
0.211 |
0.195 |
3/8 |
0.3750 |
9/16 |
0.562 |
0.551 |
0.650 |
0.628 |
15/64 |
0.243 |
0.226 |
7/16 |
0.4375 |
5/8 |
0.625 |
0.612 |
0.722 |
0.698 |
9/32 |
0.291 |
0.272 |
1/2 |
0.5000 |
3/4 |
0.750 |
0.736 |
0.866 |
0.840 |
5/16 |
0.323 |
0.302 |
5/8 |
0.6250 |
15/16 |
0.938 |
0.922 |
1.083 |
1.051 |
25/64 |
0.403 |
0.378 |
3/4 |
0.7500 |
1-1/8 |
1.125 |
1.100 |
1.299 |
1.254 |
15/32 |
0.483 |
0.455 |
|
Tolerance on Length |
Nominal Screw Size
|
Nominal Size |
Up to 1 in., incl. |
Over 1 in. to
2-1/2 in., incl. |
Over 2-1/2 in. to
4 in., incl. |
Over 4 in. to
6 in., incl. |
|
1/4 to 3/8 |
-0.03 |
-0.04 |
-0.06 |
-0.10 |
|
7/16 and 1/2 |
-0.03 |
-0.06 |
-0.08 |
-0.10 |
|
9/16 to 3/4 |
-0.03 |
-0.08 |
-0.10 |
-0.10 |
|
‡Length of a cap screw is measured from the underhead bearing surface to the extreme end of the screw.
![](hexheadtapmarks.gif)
**Product standards require the manufacturer’s head marking to appear on the top of all cap screws 1/4” diameter and larger. “X” represents one location such a marking may appear.
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