Square Nuts

Manufacturer, Exporter & Supplier of Square Nuts

Industrial Square Nuts – Precision Machined Fasteners for Structural & Mechanical Applications

Square nuts are four-sided threaded fasteners designed to provide enhanced grip, higher surface contact, and improved resistance to loosening under vibration. Widely used in heavy-duty assemblies, these fasteners are commonly manufactured in stainless steel, carbon steel, and alloy steel grades, complying with standards such as DIN 557, DIN 562, and ISO specifications. Their flat sides allow better wrench engagement and reduce rounding during installation, making them ideal for applications where frequent adjustments or high torque loads are expected.

In sectors such as construction, railways, electrical infrastructure, and machinery manufacturing, square nuts play a critical role in maintaining joint integrity. Their geometry distributes load more evenly across surfaces compared to hex nuts, especially in softer materials.

KK Fasteners supplies precision-engineered square nuts to global markets, ensuring consistent dimensional accuracy, certified materials, and reliable delivery across industrial supply chains.

Square Nuts Technical Specifications​

Parameter Details
Material Variants Stainless Steel (SS 304, SS 316, SS 316L), Carbon Steel, Alloy Steel
Grade Options A2-70, A4-70, ASTM A194 Gr. 2H, Grade 8, Grade 10
Size Range M5 to M48 / 1/4” to 2”
Thread Type Metric (ISO), UNC, UNF, BSW
Standards DIN 557, DIN 562, ISO 4032, ASTM A563
Surface Finish Plain, Zinc Plated, Hot Dip Galvanized, Black Oxide, PTFE Coated
Type Variants Standard Square Nuts, Heavy Square Nuts, Thin Square Nuts
Mechanical Properties Tensile Strength: 400–1000 MPa (depending on grade)
Hardness HRB 60–100 / HRC 20–35 (based on material grade)

Dimensions For Machine Screw Square Nut

Nut
Size
Nom.
Diameter
Width Thickness
Across
Flats
Across
Corners
Nom.
#0 0.0600 5/32 7/32 3/64
#1 0.0730 5/32 7/32 3/64
#2 0.0860 3/16 1/4 1/16
#3 0.0990 3/16 1/4 1/16
#4 0.1120 1/4 11/32 3/32
#5 0.1250 5/16 27/64 7/64
#6 0.1380 5/16 27/64 7/64
#8 0.1640 11/32 15/32 1/8
#10 0.1900 3/8 33/64 1/8
#12 0.2160 7/16 19/32 5/32
1/4 0.2500 7/16 19/32 3/16
5/16 0.3125 9/16 49/64 7/32
3/8 0.3750 5/8 55/64 1/4
This table lists the dimensions of machine screw square nuts, including nominal size presented as a number/fraction and in decimal inches. The width across flats represents the basic width, while the width across corners and thickness are calculated averages rounded to the nearest 64th of an inch.

Dimensions For Regular Square Nut

Nut
Size
Width Thickness
Across
Flats
Across
Corners
Basic
1/4 7/16 19/32 7/32
5/16 9/16 49/64 17/64
3/8 5/8 27/32 21/64
7/16 3/4 1 1/64 3/8
1/2 13/16 1 3/32 7/16
5/8 1 1 23/64 35/64
3/4 1 1/8 1 17/32 21/32
7/8 1 5/16 1 25/32 49/64
1 1 1/2 2 3/64 7/8
1 1/8 1 11/16 2 19/64 1
1 1/4 1 7/8 2 9/16 1 3/32
1 3/8 2 1/16 2 13/16 1 13/64
1 1/2 2 1/4 3 1/16 1 5/16
This table displays the dimensions of regular square nuts, including nominal size, width, and thickness in inches. The width across flats denotes the basic width, while the width across corners and thickness are calculated averages rounded to the nearest 64th of an inch.

Stainless Steel Square Nuts - Grades

  • Stainless Steel 304 Square Nuts
  • Stainless Steel 304L Square Nuts
  • Stainless Steel 304H Square Nuts
  • Stainless Steel 310 Square Nuts
  • Stainless Steel 310S Square Nuts
  • Stainless Steel 310H Square Nuts
  • Stainless Steel 316 Square Nuts
  • Stainless Steel 316L Square Nuts
  • Stainless Steel 316Ti Square Nuts
  • Stainless Steel 317 Square Nuts
  • Stainless Steel 317L Square Nuts
  • Stainless Steel 321 Square Nuts
  • Stainless Steel 321H Square Nuts
  • Stainless Steel 347 Square Nuts
  • Stainless Steel 347H Square Nuts
  • Stainless Steel 904L Square Nuts
  • Stainless Steel 410 Square Nuts
  • Stainless Steel 446 Square Nuts
  • SMO 254 Square Nuts
  • 17-4 PH Stainless Steel Square Nuts

Grades of Nickel Alloys Square Nuts

  • Inconel 600 Square Nuts
  • Inconel 601 Square Nuts
  • Inconel 625 Square Nuts
  • Inconel 718 Square Nuts
  • Incoloy 800 Square Nuts
  • Incoloy 825 Square Nuts
  • Monel 400 Square Nuts
  • Monel K500 Square Nuts
  • Nickel 200 Square Nuts
  • Nickel 201 Square Nuts
  • Hastelloy C276 Square Nuts
  • Hastelloy C22 Square Nuts
  • Hastelloy B2 Square Nuts
  • Hastelloy B3 Square Nuts
  • Hastelloy X Square Nuts

Duplex Steel Square Nuts- Grades

  • UNS S32205 Square Nuts
  • UNS S31803 Square Nuts

Super Duplex Steel Square Nuts - Grades

  • UNS S32750 Square Nuts
  • UNS S32760 Square Nuts

Inconel/Incoloy Square Nuts - Grades

  • Inconel 600 Square Nuts
  • Inconel 601 Square Nuts
  • Inconel 625 Square Nuts
  • Inconel 718 Square Nuts
  • Incoloy 800 Square Nuts
  • Incoloy 825 Square Nuts

Monel Jam Square - Grades

  • Monel 400 Square Nuts
  • Monel K500 Square Nuts

Nickel Square Nuts - Grades

  • Nickel 200 Square Nuts
  • Nickel 201 Square Nuts

Hastelloy Square Nuts - Grades

  • Hastelloy C276 Square Nuts
  • Hastelloy C22 Square Nuts
  • Hastelloy B2 Square Nuts
  • Hastelloy B3 Square Nuts
  • Hastelloy X Square Nuts

Titanium Square Nuts - Grades

  • Titanium Grade 2 Square Nuts
  • Titanium Grade 5 Square Nuts

Tantalum Square Nuts- Grades

  • UNS R05200 Square Nuts
  • UNS R05252 Square Nuts
  • UNS R05255 Square Nuts
  • UNS R05400 Square Nuts

Cupro Nickel Square Nuts - Grades

  • CuNi 90/10 Square Nuts
  • CuNi 70/30 Square Nuts

Copper Square Nuts - Grades

  • UNS C11000 Square Nuts
  • UNS C10100 Square Nuts
  • UNS C10200 Square Nuts
  • UNS C12000 Square Nuts
  • UNS C12200 Square Nuts

Carbon Steel Square Nuts - Grades

  • Carbon Steel AISI 1018 Square Nuts
  • Carbon Steel AISI 1020 Square Nuts
  • Carbon Steel AISI 1040 Square Nuts
  • Carbon Steel AISI 1045 Square Nuts

Alloy Steel Square Nuts - Grades

  • Alloy Steel 4130 Square Nuts
  • Alloy Steel 4140 Square Nuts
  • Alloy Steel 4340 Square Nuts
  • Alloy Steel 8620 Square Nuts
  • ASTM A193 Alloy Steel Gr B7 Square Nuts
  • ASTM A193 Alloy Steel Gr B7M Square Nuts
  • ASTM A320 Alloy Steel Gr L7 Square Nuts
  • ASTM A320 Alloy Steel Gr L7M Square Nuts
  • ASTM A320 Alloy Steel Gr L43 Square Nuts
  • ASTM A320 Alloy Steel Gr L43 Square Nuts
  • ISO 898-1 Alloy Steel Gr 8.8 Square Nuts
  • ISO 898-1 Alloy Steel Gr 10.9 Square Nuts
  • ISO 898-1 Alloy Steel Gr 12.9 Square Nuts

Brass Square Nuts - Grades

  • UNS C21000 Square Nuts
  • UNS C22000 Square Nuts
  • UNS C22600 Square Nuts
  • UNS C23000 Square Nuts
  • UNS C24000 Square Nuts
  • UNS C26000 Square Nuts
  • UNS C26800 Square Nuts
  • UNS C27000 Square Nuts
  • UNS C27200 Square Nuts
  • UNS C28000 Square Nuts
  • UNS C33000 Square Nuts
  • UNS C33500 Square Nuts
  • UNS C34000 Square Nuts
  • UNS C34200 Square Nuts
  • UNS C35300 Square Nuts
  • UNS C35600 Square Nuts

Aluminium Square Nuts - Grades

  • Aluminium Alloy 1050 Square Nuts
  • Aluminium Alloy 1060 Square Nuts
  • Aluminium Alloy 1060 Square Nuts
  • Aluminium Alloy 1070 Square Nuts
  • Aluminium Alloy 1080 Square Nuts
  • Aluminium Alloy 1100 Square Nuts
  • Aluminium Alloy 1145 Square Nuts
  • Aluminium Alloy 2011 Square Nuts
  • Aluminium Alloy 2014 Square Nuts
  • Aluminium Alloy 2017 Square Nuts
  • Aluminium Alloy 2024 Square Nuts
  • Aluminium Alloy 2090 Square Nuts
  • Aluminium Alloy 3003 Square Nuts
  • Aluminium Alloy 5052 Square Nuts
  • Aluminium Alloy 5083 Square Nuts
  • Aluminium Alloy 6061 Square Nuts
  • Aluminium Alloy 6063 Square Nuts
  • Aluminium Alloy 6066 Square Nuts
  • Aluminium Alloy 6082 Square Nuts
  • Aluminium Alloy 7050 Square Nuts
  • Aluminium Alloy 7075 Square Nuts

Zirconium Square Nuts - Grades

  • UNS R60700 Square Nuts
  • UNS R60702 Square Nuts
  • UNS R60704 Square Nuts
  • UNS R60705 Square Nuts
  • UNS R60706 Square Nuts

Beryllium Copper Square Nuts - Grades

  • UNS C17200 Square Nuts
  • UNS C17300 Square Nuts
  • UNS C17500 Square Nuts
  • UNS C17510 Square Nuts

Phosphor Bronze Square Nuts - Grades

  • UNS C51000 Square Nuts
  • UNS C51900 Square Nuts
  • UNS C52100 Square Nuts
  • UNS C54400 Square Nuts

Silicon Bronze Square Nuts - Grades

  • UNS C65100 Square Nuts
  • UNS C65500 Square Nuts
  • UNS C66100 Square Nuts

Key Technical Features

  • Enhanced Surface Contact Area: The square profile provides approximately 20% more surface contact than hex nuts, improving load distribution and reducing material deformation in softer substrates.
  • High Torque Resistance: Flat sides allow better wrench grip, enabling higher tightening torque without slippage during installation or removal.
  • Improved Anti-Loosening Performance: The geometry offers increased resistance to vibration-induced loosening, particularly in dynamic mechanical systems.
  • Dimensional Precision: Manufactured to DIN/ISO tolerances with controlled thread pitch accuracy, ensuring seamless compatibility with standard bolts and threaded rods.
  • Material Versatility: Available in corrosion-resistant stainless steel grades and high-strength alloy steels for demanding environmental and load conditions.
  • Coating Flexibility: Surface treatments such as hot-dip galvanizing and PTFE coatings enhance corrosion resistance for outdoor and marine applications.
  • Reusability in Maintenance Applications: Square nuts are easier to reposition and reuse, making them suitable for assemblies requiring periodic disassembly.
  • Compatibility with Slot Systems: Frequently used in T-slot channels and embedded fastening systems due to their non-rotational geometry.

Industry Applications

Square nuts are widely used in applications where high grip strength, load distribution, and ease of adjustment are critical.

  • Construction & Structural Steelwork — Used in steel framework assemblies where load-bearing joints require high stability and minimal loosening over time.
  • Railway Infrastructure — Applied in track fastening systems and signaling equipment where vibration resistance is essential.
  • Electrical & Power Distribution — Used in panel boards, transformer assemblies, and grounding systems for secure electrical connections.
  • Heavy Machinery Manufacturing — Installed in equipment frames and mechanical joints subjected to cyclic loads and stress.
  • Agricultural Equipment — Used in ploughs, tractors, and attachments where frequent maintenance and adjustments are required.
  • Marine & Offshore Installations — Stainless steel variants resist corrosion in saltwater environments.
  • Automotive & Transport Equipment — Used in chassis assemblies and body structures requiring durable fastening solutions.
  • Industrial Fabrication Workshops — Preferred for custom assemblies and retrofit applications due to ease of handling.

Manufacturing & Quality Assurance

Square nuts are typically produced using cold forging or hot forging processes, followed by precision CNC threading to achieve accurate pitch and dimensional consistency. Heat treatment processes are applied where required to enhance mechanical strength and durability.

Quality control includes thread gauge inspection, dimensional verification using calibrated instruments, hardness testing, and coating thickness measurement. Each batch is traceable through material test certificates and inspection reports.

At KK Fasteners, production follows ISO 9001-certified processes with strict adherence to international standards, ensuring consistency across bulk orders and critical applications.

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Square Nuts - FAQs

Square nuts are four-sided threaded fasteners designed to provide a larger contact surface and better grip during tightening. They are commonly used in structural and heavy-duty applications where resistance to loosening and ease of installation are important.

Stainless steel grades like SS 304 and SS 316 are widely used for corrosion resistance, while alloy steel provides higher strength for load-bearing applications. Carbon steel is suitable for general-purpose use when combined with protective coatings like zinc plating.

Square nuts are typically manufactured according to DIN 557, DIN 562, ISO standards, and ASTM A563. These standards define dimensions, tolerances, threading, and mechanical properties to ensure compatibility and performance.

Selection depends on load requirements, environmental exposure, and compatibility with bolts. Stainless steel is ideal for corrosive environments, while alloy steel is preferred for high-strength structural applications.

Choose a supplier with ISO-certified manufacturing, material traceability, and consistent export experience. KK Fasteners supplies square nuts globally with documented quality checks and compliance with international standards.

Square Nuts - Export Destination

Square Nuts Supplier in North America
Antigua and Barbuda, Bahamas, Barbados, Belize, Canada, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, Grenada, Guatemala, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, United States.
Square Nuts Supplier in South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Falkland Islands, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela.
Square Nuts Supplier in Europe
Albania, Andorra, Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic (Czechia), Denmark, Estonia, Finland, France, Germany, Greece, Holy See, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Moldova, Monaco, Montenegro, Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Russia, San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, United Kingdom.
Square Nuts Supplier in Asia
Afghanistan, Armenia, Azerbaijan, Bahrain, Bangladesh, Bhutan, Brunei, Cambodia, Cyprus, Georgia, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kazakhstan, Kuwait, Kyrgyzstan, Laos, Lebanon, Malaysia, Maldives, Mongolia, Myanmar, Nepal, Oman, Pakistan, Palestine, Philippines, Qatar, Saudi Arabia, Singapore, South Korea, Sri Lanka, State of Palestine, Syria, Taiwan, Tajikistan, Thailand, Timor-Leste, Turkey, Turkmenistan, United Arab Emirates, Uzbekistan, Vietnam, Yemen.
Square Nuts Supplier in Australia
Australia, Fiji, Kiribati, Marshall Islands, Micronesia, Nauru, New Zealand, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu.

Precision, consistency, and material reliability define the performance of square nuts in demanding applications. With controlled manufacturing processes and global distribution capability, KK Fasteners supports industrial buyers with dependable fastening solutions. For technical specifications, custom requirements, or bulk pricing, request a quote or connect with the engineering team to discuss your project needs.