Hex bolts (six sided heads) are the industry standard for fasteners with forged heads. ASTM A307  grade A bolts, all SAE hex bolts, and several other common specifications require a standard (finished) hex head. For specifications such as A307 grade B, A325 and A490 that require a heavy hex pattern, refer to dimensional tolerances for heavy hex bolts or structural bolts.

Manufacturing

Portland Bolt manufactures lag screws from 1/2″ diameter through 1-1/2″ diameter in most ASTM, AASHTO, and SAE specifications. Special tooling can be created to produce nonstandard head dimensions or bolt heads with your company’s name and/or logo.

Unless otherwise specified, nonstandard lag screws manufactured by Portland Bolt will possess a semi-cone point rather than a gimlet or cone point. A full point is unnecessary since a pilot hole nearly as large as the root diameter of the lag screw will need to be drilled prior to installation. Additionally, a gimlet point is designed for small diameter screws so they can be installed without a pilot hole. Lag screws in diameters listed in the above table do not require a gimlet point since too much torque would be required to install the large screws without drilling a pilot hole first. Without a pilot hole, the heads of the screws will often break before the lag is properly installed.

Stock

Diameters: 1/2″ – 3/4″
Lengths: 18″ maximum
Origin: Import
Finish: Plain and hot-dip galvanized

Standard Thread Length

The minimum thread length shall be equal to one-half the nominal screw length plus 1/2″ or 6”, whichever is less. One should consider longer than standard thread lengths for lag screws which are extremely long.

Note: Hex lag screws larger than 3/4″ in diameter and all square lag screws are rarely available in the marketplace as a stock item.

Hex Lag Dimensions

Click table to show drawinghex-lag
Bolt Diameter D F H Threads Per Inch Thread Dimension
Body Diameter Width Across Flats Head Height Pitch TF TD TR
Max Min Flat At Root Depth of Thread Root Diameter
12 0.515 0.482 34 1132 6 0.167 0.072 0.064 0.371
58 0.642 0.605 1516 2764 5 0.200 0.086 0.077 0.471
34 0.768 0.729 118 12 412 0.222 0.096 0.085 0.579
78 0.895 0.852 1516 3764 4 0.250 0.108 0.096 0.683
1 1.022 0.976 112 4364 312 0.286 0.123 0.110 0.780
118 1.149 1.098 11116 34 314 0.308 0.133 0.119 0.887
114 1.277 1.223 178 2732 314 0.308 0.133 0.119 1.012
138 1.404 1.346 2116 2932 3 0.333 0.143 0.128 1.119
112 1.531 1.469 214 1 3 0.333 0.143 0.128 1.244
Dimensions per ASME B18.2.1 2003

Stock Lag Screws

Length (in.) Diameter
3/8" 1/2" 5/8" 3/4"
Plain Galv. Plain Galv. Plain Galv. Plain Galv.
1 11375 11376 - - - - - -
114 11377 11378 - - - - - -
112 11379 11380 18904 18905 - - - -
134 11381 11382 - - - - - -
2 11383 11384 11413 11414 11447 11448 - -
212 11385 11386 11415 11416 11449 11450 - 19575
3 11387 11388 11417 11418 11453 11454 11489 11490
312 11389 11390 11419 11420 11455 11456 11491 11492
4 11391 11392 11421 11422 11457 11458 11493 11494
412 11393 11394 11423 11424 11459 11460 - -
5 11395 11396 11425 11426 11461 11462 11497 11498
512 11397 11398 18906 18907 18908 18909 - -
6 11399 11400 11429 11430 11465 11466 11501 11502
7 11403 11404 11433 11434 11469 11470 11505 11506
8 11407 11408 11437 11438 11471 11472 11509 11510
9 - - 11439 11440 11473 11474 11511 11512
10 11411 11412 11441 11442 11475 11476 11513 11514
11 - - - - 18910 18911 18913 18914
12 18902 18903 11445 11446 11479 11480 11517 11518
14 - - 18266 18267 11481 11482 11521 11522
16 - - 18268 18269 19597 19545 11525 11526
18 - - 18270 18271 19693 19694 11529 11530
20 - - - - - - 18915 18916
These sizes are readily available in the marketplace and Portland Bolt stocks many of them in varying quantities. If you require a size that is not listed, Portland Bolt will manufacture them.