Square Washers
Mainland Fasteners supplies a comprehensive range of Square Washers designed for structural fastening, timber construction, anchoring systems, and heavy-duty industrial applications throughout New Zealand.
Square washers are engineered to provide a substantially larger bearing surface area than conventional round washers, helping distribute loads more evenly while preventing bolts and nuts from pulling through softer materials such as timber, wood, sheet material, and structural assemblies.
In addition to standard square washers, Mainland Fasteners also stocks a specialised range of Galvanised Square Washers for projects requiring additional load distribution, packing strength, rigidity, and heavy-duty fastening support.
Typical Applications
Square washers are widely used across construction, engineering, industrial, and heavy-duty fastening industries throughout New Zealand.
- Timber Framing & Heavy Timber Construction: Prevents bolt pull-through and improves load distribution in structural timber connections, retaining walls, and pole installations.
- Concrete Anchor Bolt Systems: Used with anchor bolts, hold-downs, and base plate fastening applications.
- Structural Steel & Steel Fabrication: Covers slotted or oversized holes while improving load distribution in structural steel connections.
- Machinery & Conveyor Equipment: Suitable for heavy-duty and high-vibration fastening applications.
- Vehicle & Trailer Assembly: Provides load spreading and protection for thin materials in heavy-duty bolted joints.
- Available Thicknesses: 3mm, 6mm, 10mm, 12mm
Benefits of Square Washers
Square washers offer several advantages over traditional round washers, particularly in high-load and structural fastening applications.
| Feature | Benefit |
|---|---|
| Larger Bearing Surface | Distributes bolt load over a greater surface area to reduce material compression and pull-through. |
| Improved Stability | Provides additional support in structural timber and steel connections. |
| Resistance to Rotation | The square profile helps resist twisting or movement during installation and operation. |
| Slotted Hole Coverage | Ideal for covering oversized or slotted holes in structural steel applications. |
| Shim & Packing Capability | Can act as a spacer or packing washer in uneven or multi-surface assemblies. |
| High Vibration Performance | Suitable for heavy-duty machinery and industrial equipment subjected to vibration. |
Extra Thick Square Washers
Mainland Fasteners stocks a specialised range of Extra Thick Galvanised Square Washers designed for projects requiring additional rigidity, load distribution, and heavy-duty fastening performance.
These thicker square washers are commonly used in:
- Heavy Timber Construction
- Pole & Retaining Wall Construction
- Concrete Anchor Bolt Installations
- Structural Steel Connections
- High Clamp Load Applications
- Bridge & Infrastructure Work
Unlike standard thin washers, extra thick square washers provide increased resistance to deformation under high bolt tension and compressive loading.
In many structural fastening systems, these washers also function as shims or packing plates, helping maintain alignment and prevent distortion across multiple joined surfaces.
Galvanised Square Washer Sizes
Our galvanised square washers are available in the following configurations:
| Hole Size | Overall Square Size | Thickness |
|---|---|---|
| 16mm | 100mm x 100mm | 10mm |
| 20mm | 75mm x 75mm | 10mm |
| 20mm | 100mm x 100mm | 12mm |
| 24mm | 80mm x 80mm | 12mm |
| 24mm | 100mm x 100mm | 10mm |
| 24mm | 100mm x 100mm | 12mm |
| 30mm | 100mm x 100mm | 10mm |
| 36mm | 100mm x 100mm | 10mm |
Available Materials & Finishes
Mainland Fasteners supplies square washers in a range of materials and finishes to suit different environments and fastening applications.
| Material / Finish | Application | Benefits |
|---|---|---|
| Hot Dip Galvanised | Outdoor construction, timber framing, retaining walls, anchor systems. | Corrosion protection for exterior and structural applications. |
| 304 Stainless Steel | General outdoor and corrosive environments. | High corrosion resistance and long service life. |
| 316 Stainless Steel | Coastal and highly corrosive environments. | Superior corrosion resistance in harsh conditions. |
| Black Steel | Industrial and machinery applications. | Strong, durable washer solution for heavy-duty use. |
| Rubber | Sealing and vibration isolation applications. | Helps absorb vibration and protect surfaces. |
Square Washers vs Round Washers
While round washers are commonly used for standard fastening applications, square washers are often preferred in heavy-duty construction and structural work due to their increased stability and larger bearing surface.
| Square Washers | Round Washers | Typical Use |
|---|---|---|
| Large surface area | Smaller contact area | Structural timber and steel fastening |
| Higher load distribution | General load spreading | Heavy-duty bolt assemblies |
| Better resistance to rotation | Less rotational resistance | High vibration machinery |
| Suitable for slotted holes | Limited slotted hole coverage | Structural steel applications |
| Can function as shims | Typically not used as shims | Multi-surface assemblies |
Nationwide Supply Across New Zealand
From our Christchurch warehouse, Mainland Fasteners supplies galvanised square washers throughout New Zealand with fast nationwide shipping available across both the North Island and South Island.
Whether you require standard square washers for construction projects or specialised thick washers for structural fastening systems, our team can assist with product selection and supply.
Frequently Asked Questions
What are square washers used for?
Square washers are used to distribute bolt loads across a larger surface area while improving stability and preventing fasteners from pulling through timber, steel, or softer materials.
What is the difference between square washers and round washers?
Square washers provide a larger bearing surface area and greater resistance to rotation than standard round washers, making them better suited to structural and heavy-duty fastening applications.
Do square washers help prevent loosening?
Yes. Their square profile and increased contact area help improve stability and resistance to movement in high-vibration applications.
What are extra thick square washers used for?
Extra thick square washers are designed for heavy-duty fastening systems where additional rigidity, load distribution, and resistance to deformation are required.
Do you supply galvanised and stainless square washers?
Yes. Mainland Fasteners supplies square washers in galvanised, 304 stainless steel, 316 stainless steel, black steel, and rubber options.
Are square washers suitable for outdoor use?
Hot dip galvanised and stainless steel square washers are commonly used in outdoor and structural construction applications throughout New Zealand.
Do you supply square washers throughout New Zealand?
Yes. Mainland Fasteners supplies square washers nationwide from our Christchurch warehouse.
Request a Quote
To discuss pricing, availability, or technical specifications for square washers and extra thick galvanised square washers, contact the Mainland Fasteners team today. We can assist with structural fastening, anchor systems, timber construction, and heavy-duty industrial applications throughout New Zealand.
