Stainless Steel Square-Hole & Beveled Washers
Square-hole and taper/beveled washers for channel, I-beam, section steel and timber connections. Produced in 304 and 316/316L stainless to DIN 434 and DIN 435, with custom hole sizes and bevel angles made to your drawing.
Washers for angled and anti-rotation fastening.
Not every joint sits flat. Section steel has sloping flanges; carriage bolts must not spin; strut and timber framing need load spread over a square aperture. This family of washers solves those exact cases — a square hole to lock the fastener against rotation, or a tapered face so the bearing surface stays square to the bolt axis on an inclined flange.
We stamp both styles in 304, 316 and 316L stainless, to the established DIN profiles or to your own square size, slot or bevel angle. Bright/passivated as standard, with mill test certificates (MTC / EN 10204 3.1) available on request.
Square-hole vs. beveled — and when to use each.
They look related but solve different problems. One stops the fastener turning; the other corrects the seating angle on tapered section steel.
Square-hole washers — anti-rotation & load spread
A square (or slotted) aperture engages the square neck under a carriage bolt head, or seats over strut and channel hardware, so the fastener cannot spin while the nut is run down. The broad bearing face also spreads clamp load across slotted, oversized or soft material.
- → Carriage / coach bolts where the square neck must be held
- → Strut, channel and unistrut framing systems
- → Slotted sheet, timber and soft-material connections
Beveled (taper) washers — square seating on sloped flanges
Rolled section steel has flanges that taper toward the edge, so a flat washer would sit at an angle and bend the bolt. A taper washer has one face machined to match that slope, presenting a flat bearing surface perpendicular to the bolt axis for full, even clamp load.
- → DIN 434 — square taper washer for U-section (channel), 14% taper (~8°)
- → DIN 435 — square taper washer for I-section (I-beam), 8% taper (~4.57°)
- → Steel construction, crane rails, machine bases, bridgework
| Standard | Profile / use | Taper | Approx. angle | Section type |
|---|---|---|---|---|
| DIN 434 | Square taper washer for channel | 14% | ~8° | U-section (channel) |
| DIN 435 | Square taper washer for I-beam | 8% | ~4.57° | I-section (I-beam) |
| Custom | Made to drawing / sample | per spec | per spec | Any sloped seating face |
Made to your hole size and bevel angle.
The DIN profiles are a starting point, not a limit. Square-hole and taper washers are the kind of parts where the geometry is dictated by your section, your fixture or your bolt — so most of what we ship here is tooled to a drawing.
Send us the square aperture across the flats (or slot dimensions), the outer dimensions, the thickness, and the taper angle or the section it has to seat on. We tool it, run first-article inspection, and confirm before the main batch.
Square/slot size · outer dimensions · thickness · bevel angle or section profile · grade (304 / 316 / 316L) · finish · quantity. A sketch, photo or sample is enough to start.
Specified for the environment, certified for export.
The same square-hole or taper washer behaves very differently outdoors versus in a clean indoor frame. We match grade and finish to the duty.
304 — general structural duty
The default for indoor and sheltered steel framing, strut systems, machine bases and timber connections. Strong, cost-effective corrosion resistance for most builds.
316 — coastal & aggressive
Added molybdenum for chloride, salt-spray and chemical resistance. The grade to specify for marine, coastal, offshore and exterior structural fixings.
Finishes & certificates
Bright / passivated as standard, with polished, electropolished, black and zinc on request. Mill test certificates (MTC / EN 10204 3.1) available on request.
Square-hole & beveled washer questions.
Where are square-hole and beveled washers used?
Square-hole washers stop carriage bolts and similar fasteners from spinning in channel, strut, slotted sheet and timber, while taper/beveled washers (DIN 434 / DIN 435) sit under a nut or bolt head on the sloping flanges of channel and I-beam section steel so the load face stays perpendicular to the bolt axis. Typical uses include structural steel framing, strut and unistrut systems, machine bases, timber joinery and railway fixings.
Can you make custom square hole sizes?
Yes. Square holes, slots and special outer dimensions are stamped to your drawing or sample. Tell us the square aperture across the flats, outer dimensions, thickness and material, and we will tool and quote — first-article inspection is available before the main run.
What bevel angle should I specify?
For standard rolled section, DIN 435 beveled washers have an 8% taper (~4.57°) for I-section flanges and DIN 434 has a 14% taper (~8°) for U-section (channel) flanges. If your section or fixture uses a different slope, we can produce washers to a custom bevel angle to match the seating surface — supply the angle or a sample.
Tell us what you need.
Send specs or a drawing and we will come back with pricing, lead time and material options. No account, no minimum to ask.
- ✓ 304 / 316 / 316L, DIN & ASME or custom
- ✓ Replies from engineers, typically within one business day
- ✓ Samples and material certificates available