Hex Nuts
The hex nut is the standard six-sided nut used with bolts, cap screws, and threaded rod across virtually every industry. Eugene Fastener & Supply stocks finished hex nuts in the full grade range — Grade 2 for general use, Grade 5 and Grade 8 for higher-strength bolted joints, and Grade 9 for the most demanding assemblies — plus metric class nuts. We carry them in zinc-plated and plain steel, 18-8 and 316 stainless, brass, silicon bronze, aluminum, and nylon, in both coarse (UNC) and fine (UNF) threads.
Choosing a hex nut comes down to matching the bolt: the thread size and series must match exactly, and the nut grade should be at least equal to the bolt grade so the nut is never the weak link. For corrosion-exposed and marine work, step up to stainless or silicon bronze. Browse hex nuts by grade and material below, or contact our team for grade matching, cross-references, or bulk pricing. We sell by the piece or in bulk, with same-day shipping on orders placed before 2pm Pacific.
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Hex Nuts — Every Grade & Material
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Hex Nuts by Grade & Material
- Grade 2 Hex Nuts — low-carbon steel for general-purpose, lower-strength assembly.
- Grade 5 Hex Nuts — medium-strength; pairs with Grade 5 bolts in automotive and machinery.
- Grade 8 Hex Nuts — high-strength; for Grade 8 bolts in heavy-duty and structural-equipment joints.
- Grade 9 Hex Nuts — the highest standard strength grade for the most demanding assemblies.
- Metric Hex Nuts — class 8/10 metric nuts, coarse and fine pitch.
- 18-8 Stainless Hex Nuts — corrosion resistance for outdoor, food, and washdown service.
- 316 Stainless Hex Nuts — superior pitting resistance for marine and chloride environments.
- Brass Hex Nuts — electrical, decorative, and non-magnetic uses.
- Silicon Bronze Hex Nuts — marine and architectural; excellent salt-water corrosion resistance.
- Aluminum Hex Nuts — lightweight and non-magnetic.
- Nylon Hex Nuts — non-conductive, corrosion-proof, for light-duty and electrical work.
Hex Nut Grades & Bolt Matching
Always pair a nut with a grade at least equal to the bolt, so the nut isn’t the weak link:
| Bolt | Recommended Hex Nut |
|---|---|
| Grade 2 / low-carbon | Grade 2 hex nut (or A563 Grade A) |
| Grade 5 (SAE J429) | Grade 5 hex nut (or A563 Grade B) |
| Grade 8 (SAE J429) | Grade 8 hex nut (or A563 DH) |
| Grade 9 / alloy | Grade 9 all-metal or Grade 8 hex nut |
| Metric class 8.8 / 10.9 | Class 8 / class 10 hex nut |
| A325 / A490 structural | A563 heavy hex nut (see Heavy Hex) |
Materials, Finishes & Threads
- Finishes: zinc-plated (default), plain, and hot-dip galvanized for outdoor/structural.
- Corrosion service: 18-8 stainless for general, 316 for marine; silicon bronze for salt water; brass and aluminum for electrical and non-magnetic needs; nylon for non-conductive light duty.
- Threads: coarse (UNC) is the default and most damage-tolerant; fine (UNF) gives slightly higher strength and loosening resistance. Metric coarse and fine also stocked. The nut must match the bolt’s series and pitch exactly.
Hex Nut FAQ
What is a hex nut?
A hex nut is the standard six-sided internally-threaded fastener used with a matching bolt, cap screw, or threaded rod to clamp a joint. It’s the most common nut type, made in a range of grades (strengths) and materials for everything from general assembly to high-strength structural and corrosion-critical work.
What’s the difference between Grade 2, 5, and 8 hex nuts?
The grade indicates strength. Grade 2 is low-carbon steel for general, lower-load use. Grade 5 is medium-strength (heat-treated) for automotive and machinery. Grade 8 is high-strength alloy for heavy-duty and structural-equipment joints. Use a nut grade at least equal to the bolt grade so the nut isn’t the weak point.
What grade nut should I use with my bolt?
Match or exceed the bolt grade: Grade 2 bolt to a Grade 2 (A563 A) nut, Grade 5 bolt to a Grade 5 (A563 B) nut, Grade 8 bolt to a Grade 8 (A563 DH) nut, and metric class 8.8/10.9 bolts to class 8/10 nuts. For A325/A490 structural bolts, use A563 heavy hex nuts.
What’s the difference between a finished hex nut and a heavy hex nut?
A finished (standard) hex nut is the everyday nut for general bolting. A heavy hex nut is larger across the flats and thicker, giving more bearing surface and strength — used in structural steel and high-load joints. If your application calls out heavy hex or A563/A194, use our Heavy Hex or Structural Heavy Hex nuts instead.
Coarse or fine thread — which hex nut?
Coarse (UNC) is the default: faster to install and more tolerant of nicks and corrosion. Fine (UNF) offers slightly higher tensile strength and better resistance to loosening, used in precision and thin-wall work. The nut must match the bolt’s thread series and pitch exactly. We stock both, plus metric coarse and fine.
Which hex nut material should I use?
Zinc-plated steel for general indoor/light outdoor use; hot-dip galvanized or stainless for outdoor and structural; 18-8 stainless for general corrosion resistance and 316 for marine; silicon bronze for salt water and architectural; brass or aluminum for electrical and non-magnetic needs; nylon for non-conductive light duty.
Do you stock metric and stainless hex nuts?
Yes — metric hex nuts in coarse and fine pitch, and both 18-8 and 316 stainless across the size range, along with steel grades 2/5/8/9, brass, silicon bronze, aluminum, and nylon. If a size isn’t shown online, contact us — we source specialty sizes.
Do you sell by the piece, and can you cross-reference part numbers?
Both by the piece and in bulk. Send us any manufacturer, DIN, or legacy part number and we’ll match it to a stocked equivalent, usually the same business day, with pricing and lead time.
Why Buy Hex Nuts from Eugene Fastener
- Every grade and material — Grade 2/5/8/9, metric, 18-8 and 316 stainless, brass, silicon bronze, aluminum, and nylon.
- By the piece or in bulk — repair quantities or full production runs.
- Grade-matching & cross-reference help — send your bolt spec or any part number and we’ll match it.
- Same-day shipping on orders placed before 2pm Pacific.
- Since 1969 — serving Pacific Northwest manufacturers, contractors, and equipment makers for over 55 years.
Match your hex nuts with our hex bolts and cap screws and washers. Need vibration resistance or higher load? See our lock nuts, heavy hex nuts, and structural heavy hex nuts. Browse all nut types, or contact our sales team for grade matching, cross-references, or bulk pricing. Eugene Fastener & Supply has served Pacific Northwest manufacturers, contractors, and equipment makers since 1969.