Square Nuts
A square nut is a four-sided nut with a larger bearing surface than a hex nut of the same size. The flat sides resist rotation when seated against a flat or in a channel, and the wide face grips soft materials and spreads load — which is why square nuts are common in strut and channel framing, masonry and timber connections, machinery, and restoration or period hardware. Eugene Fastener & Supply stocks square nuts in steel, 18-8 stainless, brass, and metric.
Square nuts pair with square-head bolts, carriage bolts, and strut channel, and they’re the right call where a wrench can only reach one face or where you want the nut to seat without spinning. We sell by the piece or in bulk, cross-reference part numbers, and ship same day on orders placed before 2pm Pacific.
Goes Well With
Square Nuts — Steel, Stainless, Brass & Metric
Need square nuts for a production run, strut work, or a restoration?
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Square Nuts by Material
- Steel Square Nuts — zinc/plain, the general-purpose choice.
- Stainless Square Nuts — 18-8 corrosion resistance.
- Brass Square Nuts — electrical, decorative, non-magnetic.
- Metric Square Nuts — coarse pitch.
For strut framing, see also our channel (spring) nuts designed to drop into strut channel.
When to Use a Square Nut
- Anti-rotation: the flat sides keep the nut from spinning when seated against a flat or held in a channel or recess.
- Grip on soft materials: the larger bearing face spreads load on wood, masonry, and soft metals.
- One-wrench access: a wrench can drive the nut from a single exposed face.
- Restoration / period hardware: square nuts and square-head bolts match historic assemblies.
Square Nut FAQ
What is a square nut?
A square nut is a four-sided nut with a larger bearing surface than a hex nut of the same thread size. The flat sides resist rotation when seated against a flat or held in a channel, and the wide face grips soft materials and spreads load. Common in strut and channel framing, masonry and timber, machinery, and restoration hardware.
Where are square nuts used?
Strut and channel framing, masonry and timber connections, machinery, sign and rail assemblies, and restoration or period hardware. They’re chosen where anti-rotation, a large grip face, or single-wrench access matters — or to match square-head bolts and carriage bolts.
Square nut vs. hex nut — what’s the difference?
A hex nut has six sides for wrench access from multiple angles and is the general standard. A square nut has four sides, a larger bearing surface, and better anti-rotation when seated against a flat or in a channel. Use square nuts for grip, anti-rotation, and channel/strut or restoration work; hex for general bolting.
What’s the difference between a square nut and a strut channel nut?
A standard square nut seats against a flat surface. A channel (spring) nut is shaped to drop into and grip the lips of strut channel, often with a spring. For strut framing use channel nuts; for general anti-rotation use square nuts. We stock both.
What materials are available?
Steel (zinc and plain), 18-8 stainless, brass, and metric — in coarse threads, with fine and specialty sizes to order.
Do you sell by the piece and cross-reference part numbers?
Both by the piece and in bulk. Send any manufacturer or DIN part number and we’ll match it, usually same business day.
Why Buy Square Nuts from Eugene Fastener
- Steel, stainless, brass, and metric in one place.
- Strut, masonry, machinery, and restoration applications covered — plus channel nuts for strut.
- By the piece or in bulk, with cross-reference help.
- Since 1969 — serving Pacific Northwest industry for over 55 years.
Square nuts pair with square-head and carriage bolts and drop into strut and channel (see also channel nuts). Browse all nut types, or contact our sales team for specialty sizes or bulk pricing. Eugene Fastener & Supply — serving the Pacific Northwest since 1969.