Knurled washers convert clamp load into mechanical bite. When tightened, the raised teeth press into the mating surface, creating hundreds of micro-interlocks that resist rotational slip.
Two patterns are common: straight knurl for directional resistance and diamond knurl for multi-directional grip in vibration-prone assemblies.
Unlike tab washers or saddle washers, knurled washers are not positive mechanical locks or surface-conforming elements. They are best suited for joints where light surface indentation is acceptable in exchange for stronger rotational resistance.
Where Knurled Stainless Washers Earn Their Keep
Electrical grounding & enclosure hardware
Knurls cut through paint, anodizing, and oxide films to establish metal-to-metal contact - a common requirement for panel grounding kits and RF enclosure assemblies.
Composite & reinforced-plastic clamping
FRP and glass-filled polymers tolerate clamp load far better when a knurled face distributes and anchors it, preventing the creep-induced loosening typical of plastic joints.
Custom knife & tool hardware
Pivot and scale washers for folding knives are a signature small-batch application: 17-4PH or 316 blanks, mirror faces on one side, knurled or textured on the other.
Marine & food-equipment fastening
316 washers hold rigging and sanitation fittings where flat washers walk loose under vibration and washdown.
Instrumentation & optical mounts
Fine-pitch straight knurls let technicians dial in alignment and re-tighten without marking precision ground faces.
Preparing a Drawing That Speeds Up Your Quote
Because knurled washers are manufactured to print, the drawing defines every critical detail. Include these seven items to help ensure an accurate quote on the first review:
- OD, ID, and thickness with tolerances
- Knurl pattern (straight or diamond), pitch (0.4 / 0.5 / 0.6 mm standard), and tooth height requirements
- Knurled face location referenced from a clear datum
- Flatness and parallelism requirements for clamping surfaces
- Edge break specifications (chamfer or radius)
- Material grade and surface treatment requirements
- Annual volume and revision breakdown for production planning
STEP files are preferred, while DWG and PDF drawings are also accepted. First-article inspection reports are available for every new part number. Send your drawing through the Request a Quote page or explore the full fasteners catalog for related solutions.
Frequently Asked Questions
Can a knurled washer replace a spring lock washer?
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In many vibration applications, yes. Spring lock washers rely on elastic tension and friction, which can decrease after settling. Knurled washers create mechanical interlock through surface indentation, providing more consistent rotational resistance. The trade-off is surface marking, which may not suit visible or coated assemblies.
Will knurls damage the mating surface?
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Knurled teeth create shallow surface impressions that vary with material hardness, knurl geometry, and clamp load. These marks are acceptable on most structural parts but may not suit precision sealing or cosmetic surfaces. For mixed requirements, we can manufacture a two-face washer with one knurled side and one flat side.
Will stainless steel knurled washers gall against stainless fasteners?
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The reduced contact area of knurled surfaces can lower galling risk compared with flat-on-flat contact. Washers are passivated as standard, and dry-film lubricant can be specified for high-torque stainless applications.
Is CNC milling cost-effective for production volumes?
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For many washer designs, CNC milling remains competitive up to tens of thousands of pieces per year through multi-part fixturing and automated cycles. For higher volumes, stamping may become more economical, and we can help evaluate the transition.
Are knurled washers suitable for electrical grounding?
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Yes. The teeth can break through oxide layers, paint, or anodizing to create a reliable metal-to-metal contact path, maintaining conductivity in vibration environments.
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