Home/Products/Nuts/Square Nuts

Square Nuts

DIN 557 Stainless Steel Square Nuts for Industrial Fastening

VALTOR supplies DIN 557 square nuts with a four-sided outer profile for machinery, sheet metal fabrication and industrial fastening assemblies. Stainless steel options support applications requiring corrosion resistance, clean appearance and reliable thread compatibility.

Product
Square Nuts
Standard
DIN 557
Material
304 / 316 Stainless Steel / Carbon Steel
Thread
Metric / Other Threads on Request
Type
Standard Square Nut
Profile
Four-Sided Square Outer Shape
Size
Standard / Custom Sizes
Application
Machinery / Sheet Metal / Industrial Fastening
Customization
Drawing / Sample Based Production Available

Request A Quote

Product Overview

Square nuts are internally threaded fasteners with a four-sided outer shape. They are commonly used in machinery, sheet metal fabrication and industrial assemblies where the connection design benefits from a square profile, increased surface contact or anti-rotation support from a retaining pocket.

Compared with six-sided hex nuts, square nuts provide a distinct wrenching and contact geometry. Selection depends on installation space, tool access and the way the nut is retained in the assembly.

VALTOR supplies DIN 557 square nuts in 304 and 316 stainless steel for corrosion-resistant applications. Carbon steel and alternative finishes such as zinc plated or black oxide can be supplied according to requirement, while stainless versions are available natural or passivated.

Technical Specifications

Product
Square Nuts
Alternative Name
DIN 557 Square Nuts / Industrial Square Nuts
Standard
DIN 557 / Other Specifications on Request
Material
304 Stainless Steel / 316 Stainless Steel / Carbon Steel
Thread
Metric Thread / Other Thread Types on Request
Type
Standard Square Nut
Size
Standard Sizes / Custom Sizes Available
Finish
Natural / Passivated / Zinc Plated / Black Oxide
Application
Industrial Fastening / Machinery Assembly / Sheet Metal Fabrication
Customization
Drawing / Sample Based Production Available

Square Profile & Captive Assembly Fit

DIN 557 square nuts use a four-sided external body with a central internal thread, providing broad flat faces that can be located or restrained by a correctly designed surrounding component.

Square External Profile
The square body differs from a conventional hex nut and can be useful where the nut is held, captured or positioned by the assembly.
Captive / Anti-Rotation Assembly
Inside a correctly sized square recess, channel, slot or fabricated retaining feature, the external faces can help prevent rotation while the bolt is tightened. This depends on the surrounding geometry; the nut is not universally self-locking.
Bearing & Contact Area
The square body can provide a relatively broad contact area against a suitable mating surface, but this assembly characteristic does not establish a universal load capacity.
Assembly Accessibility
Useful where access for holding a conventional nut is limited, the nut must remain located before bolt installation, a fabricated retaining feature is provided, or repeated assembly requires predictable positioning.
Thread Matching
Confirm nominal diameter, pitch, thread system, material, mechanical requirement and finish for the mating bolt, screw, stud or threaded component.

Material, Thread & Finish Options

Material, thread and finish should suit the mating fastener, assembly material and service environment.

1304 Stainless Steel — Suitable for general industrial equipment, fabricated assemblies and applications requiring good corrosion resistance.
2316 Stainless Steel — Suitable for humid, outdoor, coastal and more corrosive industrial environments.
3Carbon Steel Options — May be supplied where cost, mechanical requirements or a specified surface treatment make carbon steel suitable.
4Thread Options — Confirm diameter, pitch, metric specification, specifically required and available alternative systems, and application requirements. Incompatible systems must not be mixed.
5Material Selection — Consider corrosion environment, indoor or outdoor use, mating fastener, assembly material, mechanical requirement and project specification.
Relevant Surface Finish Options
Natural Stainless SteelPassivated Stainless SteelZinc Plated Carbon SteelBlack OxideOther Specified Finishes

Finish availability depends on the base material and order specification; not every finish is suitable for every material.

Quality Control & Dimensional Inspection

Inspection focuses on mating-thread fit and the square external profile needed for reliable captive or retained assembly.

Thread Inspection
Square Body Inspection
Squareness & Profile Inspection
Assembly Fit
Material & Surface Inspection

Thread inspection covers diameter, pitch, quality and mating fit. Square-body checks may include body width, height or thickness, thread position and overall geometry. Profile inspection can cover opposite-face parallelism where applicable, consistency, burrs, edges and visible deformation. For captive or slot-based orders, fit may be checked against a customer drawing, sample, specified slot or retaining-feature dimensions. Available documentation may include a Material Certificate / MTC, raw material report, dimensional inspection report or third-party inspection support.

OEM Supply, Matching Fasteners & Packaging

OEM Square Nut Solutions

Supply can follow DIN 557 or drawings, samples, special external dimensions, thickness, thread and slot or recess geometry. A product differing from DIN 557 is identified as a custom square nut unless it actually complies with the standard.

Matching Fastener Supply
Hex BoltsApplicable Machine ScrewsStudsThreaded RodsFlat Washers

Compatibility is confirmed by thread, material, finish and assembly requirement.

Information Required for Quotation

Provide DIN 557 or the custom specification, thread size and pitch, custom square dimensions, nut height, material, finish, quantity, application or slot dimensions and an available drawing or sample.

Export Packaging
Inner BagsSmall BoxesExport CartonsWooden PalletsBulk Packing
Customer Packaging

Customer labels, part numbers, carton markings, packing quantities and customer-authorized private-label packaging can be supported. Physical VALTOR engraving is not implied.

Delivery Basis

Delivery depends on standard or custom dimensions, thread, material, finish, quantity, inspection requirements and current production availability.

Applications

Four-sided fastening solutions for machinery, fabrication and industrial assembly.

Stainless steel square nut held in a retaining pocket and engaged with a threaded rod in industrial machinery
01

Machinery Assembly

Provides a practical retained-nut option for machinery frames and mechanical assemblies.

02

Sheet Metal Fabrication

Used in fabricated brackets and pockets designed to hold the square profile against rotation.

03

Industrial Equipment

Supports threaded connections in production equipment and industrial hardware.

04

Custom Hardware Assemblies

Available for custom hardware requiring specific dimensions, materials or packaging.

05

General Industrial Fastening

Suitable for general connections where a DIN 557 square nut profile is specified.

Frequently Asked Questions

What are square nuts used for?

Square nuts are used in machinery, sheet metal fabrication and industrial fastening assemblies where a square outer profile is preferred for the connection design.

What is the difference between square nuts and hex nuts?

Square nuts have a four-sided outer shape, while hex nuts have a six-sided outer shape. The selection depends on installation requirements, tool access and assembly design.

When should I choose stainless steel square nuts?

Stainless steel square nuts are commonly selected for applications requiring corrosion resistance, cleaner surface appearance or outdoor/environmental durability.

Can square nuts be supplied in custom sizes and packaging?

Yes. VALTOR can supply square nuts according to size requirements, packaging preferences and other project specifications.

How are square nuts packaged for export shipment?

Square nuts can be packed in bags, cartons, boxes or customized export packaging according to quantity and customer requirements.

Need DIN 557 Square Nuts?

Share the required material, thread size, quantity, packaging and documentation requirements with VALTOR.

Request A Quote




Scroll to Top