Aerospace Washers
Roughly 6,800 washers across flat, structural, countersunk, and lock styles. AN960 and NAS1149 flat washers, AN970 heavy series, MS20002C countersunk washers, and MS35338 lock washers in cadmium-plated steel, CRES, and aluminum, ready to order with full AS9120 traceability.
Aerospace Washer Types
From legacy AN960 flats to the NAS1149 coding system and MS35338 lock washers, we cover the washer families called out across commercial and military aircraft drawings.
Flat Washers
The everyday washers under nuts and screw heads across the airframe. NAS1149 superseded the classic AN960 series for most new callouts, and its part number encodes material, finish, and thickness, so the exact code on your drawing is the part to order.
Heavy & Structural Washers
AN970 large-area flat washers spread bolt load over a wider footprint than standard washers. They protect wood, composite, and thin sheet structure from crushing and are typically supplied in cadmium-plated steel.
Countersunk Washers
Machined washers for high-strength bolted joints. The MS20002C style carries a countersunk face that clears the head-to-shank fillet radius of internal-wrenching bolts, while the plain MS20002 version typically sits under the nut.
Lock Washers
MS35338 helical spring lock washers resist loosening under vibration on machine screws and equipment hardware. Tooth-type lock washers, such as the MS35333 internal-tooth series, serve smaller electrical and avionics installations.
Washer Materials & Finishes
Cadmium-Plated Steel
The default choice for washers paired with plated alloy steel fasteners. Carbon and alloy steel washers with cadmium plate provide corrosion protection and galvanic compatibility with classic AN and NAS fastener finishes.
CRES (Corrosion-Resistant Steel)
Passivated stainless washers for corrosive environments and higher-temperature zones such as engine and nacelle areas, typically paired with CRES fasteners so the joint shares one corrosion behavior.
Aluminum Alloy
Lightweight washers in alloys such as 2024 and 5052, used where weight matters and where galvanic compatibility with aluminum structure is required. Common under screw heads on skins, panels, and equipment.
Finishes & Variants
Cadmium plate, passivation, and anodize finishes, plus reduced-thickness and light-series variants within the NAS1149 coding system. Order the exact dash code from your drawing, since it defines material, finish, and thickness together.
How to Order Aerospace Washers
Search by Part Number
Enter your AN960, NAS1149, AN970, MS20002, or MS35338 washer part number, including the dash code for size, material, and finish, and review the available options.
Get a Fast Online Quote
Add the quantities you need to your quote. Compare options sourced from our approved suppliers on price, lead time, and minimum order quantity.
Order with Confidence
Check out securely online. Every shipment includes certificates of conformance backed by our AS9120 Rev B quality management system.
Your Distribution Partner for Aircraft Washers
With roughly 6,800 washer line items in the Instaparts catalog of 266,000+ aerospace parts, we cover the hardware that sits under nearly every fastener on an aircraft. Washers look simple, but they do real engineering work: they distribute bolt preload, protect surface finishes, fine-tune grip length, and back up locking elements. The drawing callout defines the material, finish, and thickness, and substituting "a washer that fits" is never acceptable in aerospace. The part must arrive with documentation proving it is what it claims to be.
The specification landscape is compact but precise. AN960 flat washers remain on thousands of legacy drawings, while the NAS1149 system covers most current callouts with a part number that encodes material, finish, and thickness in a single code. AN970 provides large-area structural washers for wood, composite, and thin sheet installations. For high-strength bolted joints, MS20002 machined washers and their MS20002C countersunk companions protect the fillet radius of internal-wrenching bolts. MS35338 split lock washers and tooth-type styles round out the family on equipment and avionics hardware. Instaparts catalogs all of these families, so you can search and quote by exact part number.
Every washer we supply moves through our AS9120 Rev B certified quality management system. Instaparts, a division of RFQ2Go, Inc. based in Toronto, Canada, sources exclusively from approved suppliers and applies counterfeit-prevention controls aligned with AS6081. Shipments include certificates of conformance, and lot traceability is maintained from receipt through delivery, so a bag of washers can be traced just as rigorously as a flight-critical bolt.
Washers rarely appear alone on a drawing. The same bill of materials typically calls out aerospace bolts and aerospace nuts for the joint itself, and aerospace screws for panels and equipment. If your requirement covers multiple categories or a long bill of materials, send it through our quote page and our team will price the complete package.
Aerospace Washer FAQs
What is the difference between AN960 and NAS1149 washers?
NAS1149 is the newer standard that superseded the classic AN960 flat washer for most applications. The two are dimensionally similar and published cross references exist, but the drawing callout governs. If your drawing specifies AN960, order AN960; if it specifies a NAS1149 code, order that exact code, since the part number also defines material, finish, and thickness.
When is a countersunk washer such as MS20002C required?
MS20002C washers are machined washers with a countersunk face that clears the head-to-shank fillet radius of high-strength internal-wrenching bolts. The countersunk washer goes under the bolt head, while the plain MS20002 style typically goes under the nut. Using an ordinary flat washer in that position can load the fillet radius and damage the bolt.
What are AN970 washers used for?
AN970 is a large-area structural washer with a much bigger outside diameter than AN960. It spreads bolt load over a wider footprint and is commonly called out on wood, composite, and thin sheet structure where a standard washer would crush or dish the surface.
Do lock washers replace self-locking nuts?
No. MS35338 split lock washers and tooth-type styles resist loosening on machine screws and general equipment hardware, but the locking method for any aerospace joint is defined by the engineering drawing. Never substitute one locking approach for another without engineering authority.
What documentation comes with your washers?
Instaparts operates an AS9120 Rev B certified quality management system. Orders ship with certificates of conformance, lot traceability is maintained back to our approved suppliers, and counterfeit-prevention controls aligned with AS6081 are applied across our hardware supply chain.
Need Aerospace Washers?
Browse the catalog by AN960, NAS1149, AN970, MS20002, or MS35338 part number and get a fast online quote with full AS9120 traceability.
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