Square Plate Washers
Valley Nut & Bolt makes square plate washers in stock sizes of 2" to 4" and up, plus custom square plate washers cut, punched, and finished to your drawing. Choose A36 carbon steel or stainless steel, plain or hot-dip galvanized in our own Olympia, WA facility, with full product traceability on every order.
Send Us Your Square Plate Washer Spec
Share your drawing or the five details above and our team will return a quote on stock or custom square plate washers. Call 360-754-4877 or request a quote online.
Why Specify a Square Plate Washer
A square plate washer puts more steel under the nut than a round washer of the same width. A 3" square covers about 27% more bearing area than a 3" round washer, which is why engineers call for square profiles where the base material is wood or concrete and pull-through or crushing is the failure to prevent.
The flat edges also sit square to a sill plate, beam, or ledger and resist turning as the nut is tightened, so the washer stays where it was placed. Square plate washers are common in:
- Sill plate and mudsill connections over anchor bolts in wood framing
- Seismic retrofit, shear wall, and wind-load connections
- Through-bolted timber and heavy timber construction
- Concrete anchor rod installations using ASTM F1554 anchor bolts or all thread rods
How to Specify a Custom Square Plate Washer
Five details define a custom square plate washer. Get them on the drawing or the RFQ and we can quote and build without back-and-forth.
The hole starts with bolt or rod diameter plus clearance. Anchor rod work often calls for an oversized or slotted hole so the washer can bridge placement tolerance in the concrete. Our CNC turret punching produces round, oversized, slotted, or offset holes to the dimension on your print.
Side length sets bearing area, so softer base materials and higher loads need a larger square. Thickness keeps the plate from cupping as the nut is torqued down. We carry stock square plate washers 2" to 4" and larger and cut non-standard sizes and thicknesses to order.
A36 carbon steel covers most structural and timber work. Stainless steel suits connections exposed to salt air, chemicals, or treated lumber where a coating alone is not enough.
Plain or black finish works for dry, interior connections. For outdoor, marine, or high-moisture service, we hot-dip galvanize to ASTM A153 in-house after cutting and punching, so the hole and cut edges carry the same zinc coating as the faces. Our kettle runs a 100% lead-free zinc bath.
What to Include in Your Quote Request
- Bolt or rod diameter and the hole size or slot dimensions
- Outside dimension (side length) and thickness
- Material: A36 carbon steel or stainless steel
- Finish: plain, black, or hot-dip galvanized
- Quantity, required delivery date, and a drawing if you have one
Made, Punched, and Galvanized Under One Roof
Plate washers often pass through a separate fabricator and a separate galvanizer before they reach the job site. We handle cutting, punching, forming, and hot-dip galvanizing in-house, which removes two handoffs from the schedule and keeps quality checks with one team. See our full custom manufacturing capabilities.
Valley Nut & Bolt has supplied fasteners and custom hardware since 1969. Square plate washers ship nationwide, with our own fleet covering job sites along the I-5 corridor between Seattle and Portland. Pair them with matching heavy hex nuts and anchor hardware on the same order. Back to all plate washers.
Frequently Asked Questions About Square Plate Washers
Start with the bolt or rod diameter, which sets the hole size. The load on the connection and the material you are bearing against, whether wood, concrete, or steel, set the side length and thickness. When an engineer’s drawing or local building code specifies a size, we build to that spec.
Yes. Our CNC turret punching produces slotted, oversized, and offset holes in custom square plate washers. Slotted and oversized holes are common on anchor rod connections where the washer needs to cover placement tolerance in the concrete.
Yes. We hot-dip galvanize square plate washers to ASTM A153 in our own facility after they are cut and punched. That way the hole and cut edges are coated along with the faces, which matters most in outdoor and marine service.
A square plate washer spreads the nut’s load across a larger area of the sill plate, which keeps the wood from crushing and the bolt from pulling through under seismic or wind load. Building codes in high seismic regions often call for them on sill plate anchors, so check the requirements for your jurisdiction.
Both. We supply stock square plate washers 2" to 4" and larger in multiple thicknesses, and we fabricate custom square plate washers in non-standard dimensions, thicknesses, and hole patterns.
Yes. We supply square plate washers at volume to contractors, fabricators, and industrial buyers nationwide, with our own fleet delivering along the I-5 corridor. Every order includes full product traceability.
Ask Our Team
Give us a call or fill out the form and one of our team members will be in touch as soon as possible to answer your questions.
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