SteelA307 Grade APlain
318430-30
1 5/8"-5 Heavy Hex Nut / Grade A Steel / Plain
$297.89
Bulk Box (30 pcs)
$297.89
Heavy Hex Nuts
377 products
Heavy hex nuts are larger across the flats and thicker than standard hex nuts of the same thread size, providing greater bearing area and strength to match high-strength and structural bolts. They are specified for A325/A490 structural connections and demanding industrial joints. We stock heavy hex nuts in the structural grades and materials that pair with high-strength bolts.
Why Heavy Hex
The larger, thicker body develops the full strength of a high-strength bolt without stripping, and the wider flats accept the larger wrenches used in structural work. Pairing a structural bolt with a standard nut risks thread stripping under high preload — heavy hex nuts are sized to carry the load.
Grades
ASTM A563 Grade DH: the structural standard, matched to A325 and A490 bolts. ASTM A194 Grade 2H: high-temperature, high-pressure service, paired with B7 stud bolts in flanges. A563 Grade A/B/C: lower grades for less demanding joints. Always match the nut grade to the bolt grade.
Finishes
Plain for protected structural use and hot-dip galvanized for exterior exposure. Galvanized structural nuts are over-tapped to fit galvanized bolts — match galvanized nuts with galvanized bolts.
Dimensional Standards
Heavy hex nuts conform to ASME B18.2.2 for dimensions, with grades per ASTM A563 (structural) and A194 (high-temp/pressure).
Selecting the Right Heavy Hex Nut
Match the nut grade to the bolt — A563 DH for A325/A490 structural, 2H for B7 studs. Choose galvanized to match galvanized bolts, and use the correct hardened washer for structural joints. Verify thread pitch and follow the specified installation method for proper preload.
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SteelA307 Grade APlain318420-301 1/2"-6 Heavy Hex Nut / Grade A Steel / Plain
$118.23 – $158.35Bulk Box (30 pcs) $158.35
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$58.62 – $196.29Bulk Box (75 pcs) $196.29
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$43.19 – $128.53Bulk Box (100 pcs) $128.53
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$30.23 – $134.96Bulk Box (150 pcs) $134.96
SteelA307 Grade APlain318210-4005/8"-11 Heavy Hex Nut / Grade A Steel / Plain
$29.60 – $140.96Bulk Box (400 pcs) $140.96
SteelA307 Grade APlain318240-2503/4"-10 Heavy Hex Nut / Grade A Steel / Plain
$44.29 – $131.81Bulk Box (250 pcs) $131.81
SteelA307 Grade APlain318150-8001/2"-13 Heavy Hex Nut / Grade A Steel / Plain
$37.25 – $177.36Bulk Box (800 pcs) $177.36
SteelA307 Grade APlain318120-10007/16"-14 Heavy Hex Nut / Grade A Steel / Plain
$77.78 – $231.50Bulk Box (1,000 pcs) $231.50
SteelA307 Grade APlain318180-5009/16"-12 Heavy Hex Nut / Grade A Steel / Plain
$66.22 – $197.09Bulk Box (500 pcs) $197.09
SteelA307 Grade APlain318030-40001/4"-20 Heavy Hex Nut / Grade A Steel / Plain
$16.09 – $191.60Bulk Box (4,000 pcs) $191.60
SteelA307 Grade APlain318090-15003/8"-16 Heavy Hex Nut / Grade A Steel / Plain
$34.46 – $153.82Bulk Box (1,500 pcs) $153.82
SteelA307 Grade APlain318060-30005/16"-18 Heavy Hex Nut / Grade A Steel / Plain
$24.29 – $216.88Bulk Box (3,000 pcs) $216.88
Steel2HPlain314983-203"-4 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,156.86Bulk Box (20 pcs) $1,156.86
Steel2HPlain314980-332 1/2"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,076.27Bulk Box (33 pcs) $1,076.27
Steel2HPlain314972-951 3/4"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$17.24Bulk Box (95 pcs) $17.24
Steel2HPlain314974-801 7/8"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,151.17Bulk Box (80 pcs) $1,151.17
Steel2HPlain314979-422 1/2"-4 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,369.80Bulk Box (42 pcs) $1,369.80
Steel2HPlain314978-482 1/4"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,224.63Bulk Box (48 pcs) $1,224.63
Steel2HPlain314977-482 1/4"-4 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$8.71Bulk Box (48 pcs) $8.71
Steel2HPlain314912-23 1/2"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$211.70Bulk Box (2 pcs) $211.70
Steel2HPlain314971-951 3/4"-5 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,156.90Bulk Box (95 pcs) $1,156.90
Steel2HPlain314975-652"-4 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,160.40Bulk Box (65 pcs) $1,160.40
Steel2HPlain314976-652"-8 Heavy Hex Nut / 2H Medium Carbon Steel / Plain
$1,126.60Bulk Box (65 pcs) $1,126.60
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