Patriot Bolt supplies washers in carbon, alloy, stainless and nickel grades, to standard dimensions or to your drawing, with mill test reports on every order. Our flat washers include plain washers, SAE and USS pattern washers, fender washers and through-hardened washers for flanged joints.
Custom and oversize flat washers are cut on our CNC fiber laser or turned on our CNC lathes in Humble, Texas, so special ID, OD and thickness combinations don’t need tooling. Send us a size, a standard or a drawing and we will quote it.
Flat Washers at a Glance
- Types
- Plain (Type A and Type B), SAE and USS pattern, fender, through-hardened, custom
- Standards
- ASME B18.22.1 plain washers, ASTM F436 hardened steel washers, or your drawing
- Materials
- Carbon, alloy, stainless and nickel grades
- Finish
- Plain finish, zinc electroplated, zinc-nickel or PTFE fluoropolymer coated
- Custom washers
- CNC fiber laser cut from plate, or CNC turned from bar
- Laser capacity, typical
- Mild steel 1/2 in, stainless 5/16 in thick; 5 × 10 ft sheet
- Paperwork
- Mill test reports on every order
Flat Washer Types
- Plain washers, Type A: wide tolerance plain washers in SAE (narrow) and USS (wide) patterns. See the Type A plain washer chart.
- Plain washers, Type B: closer tolerance washers in narrow, regular and wide series. See the Type B plain washer chart.
- Fender washers: a large OD on a small ID to spread load over thin or soft material. See the fender washer chart.
- Hardened steel washers: through-hardened washers to ASTM F436 for structural and flange bolting. See the ASTM F436 chart.
- Custom flat washers: special ID, OD, thickness or material, cut or turned to your drawing.
Through-Hardened Flange Washers
Washers are optional on pressure-boundary flanged joints, but when they are used they should be through-hardened. A hard, flat bearing face under the nut keeps the nut factor consistent and protects the flange face.
We supply through-hardened flange washers to your specification together with the stud bolts and nuts. Read more in Through-Hardened Flange Washers, and remember to allow for washer thickness in the stud length.
Materials and Finishes
We supply flat washers in carbon, alloy, stainless and nickel grades. Match the washer material to the bolt and nut, especially in corrosive service, so the joint does not set up a galvanic couple. Compare alloys in our Fastener Materials Matrix.
Finishes: plain finish, zinc electroplated, zinc-nickel or ptfe fluoropolymer coated. Tell us the coating and any thickness requirement on your order.
What to Send Us
To quote flat washers, tell us:
- Type and size, or the standard (for example ASME B18.22.1 or ASTM F436).
- ID, OD and thickness for custom washers, or send a drawing or DXF file.
- Material and grade, and any hardness requirement.
- Finish.
- Quantity and packing or labeling needs.
Flat Washers FAQ
What are flat washers used for?
Flat washers spread the load from a nut or bolt head over a larger area, protect the surface under the fastener and give the nut a smooth bearing face.
What is the difference between SAE and USS washers?
Both are plain washers. USS pattern washers have a larger outside diameter and are thicker; SAE pattern washers are narrower and fit closer to the bolt.
Do you make custom flat washers?
Yes. Custom flat washers are cut on our CNC fiber laser or turned on our CNC lathes to your ID, OD, thickness and material.
Should I use washers on a flanged joint?
Washers are optional, but when they are used on pressure-boundary flanges they should be through-hardened. See our Through-Hardened Flange Washers page.
What materials are available?
Carbon, alloy, stainless and nickel grades, with mill test reports on every order.
Request a Quote
Send us the size, standard or drawing, with material, finish and quantity. Our team will confirm the details and lead time. Call (281) 581-0176 or request a quote.
Related: Washers · Lock washers · Spring washers · Specialty shims · Fastener Materials Matrix