EKINSUN is a custom parts manufacturer that makes washers to drawing when the size range stops: a bore and outside diameter no table pairs, a thickness between the standard ones, a large-OD washer in 316L, a copper or PEEK sealing ring of an odd size, a tab washer for a specific nut. The size ranges are those a distributor stocked in 2026.
A typical request: twelve stainless washers with a 30 mm bore, 70 mm outside and 6 mm thick, where every catalogue stops at 3 mm thick or 60 mm outside.
Thick and wide is where washers leave the shelf; odd bores are the other reason.
Washer types chart
Washers fall into five jobs: load spreading (flat ISO 7089, large ISO 7093, square DIN 436), locking (tooth DIN 6797, serrated DIN 6798, wedge-lock DIN 25201, tab DIN 93 / 432 / 463), spring load (spring DIN 127, wave DIN 137, disc DIN 2093), sealing (bonded washers, copper rings DIN 7603) and seating (spherical DIN 6319, taper DIN 434 / 435), in sizes from M1.6 to M118 and mostly in 304 stainless or zinc-plated steel.
| Type | Standard | Job | Size range | Common materials |
|---|---|---|---|---|
| Flat washer | ISO 7089 / DIN 125 (A / B) | load spreading, surface protection | M1.6–M52 | 304, zinc, black, nickel, hot-dip steel, brass M2–M33, aluminium M5–M24, titanium M3–M20, nylon, PEEK |
| Large (fender) washer | ISO 7093 / DIN 9021 | load spreading on thin or slotted sheet | M3–M24 | 304, zinc steel |
| Small washer | ISO 7092 / DIN 433 | under socket cap screws | M2–M24 | 304 |
| Shim (thin) washer | DIN 988 | gap filling, fine adjustment | M3–M40 | 304 |
| Spring (split) lock washer | DIN 127 (A / B); DIN 7980 for socket screws | take-up of settling; little locking | M1.6–M36; heavy M6–M20 | 304, zinc and black steel, phosphor bronze M2.5–M20, titanium |
| Tooth lock washer, internal / external | DIN 6797 (J / A) | bites into the face; earth contact through paint | M2.5–M30 | 304, zinc steel |
| Serrated lock washer, internal / external / countersunk | DIN 6798 (J / A / V) | as tooth washers, finer teeth | M2–M33 | 304, zinc steel |
| Double-sided serrated (ribbed) washer | maker series | locks against both faces | M3–M42 | 304, zinc steel |
| Wedge-lock washer pair | DIN 25201-4 (Nord-Lock type) | real locking by cam action under vibration | M3–M42; NL3–NL24 | zinc-flake spring steel 65Mn, 304 / 316 |
| Wave washer | DIN 137 (A curved / B wave) | light spring load, axial take-up, rattle stop | M3–M118 | 304, spring steel |
| Disc spring (Belleville) | DIN 2093 | high spring load in a short stack | M3–M40 | spring steel, 304 |
| Conical spring washer | DIN 6796 | spring load under a bolt head | on request | spring steel |
| Square washer | DIN 436 | timber and channel; cannot rotate | M3–M30 | 304, zinc steel |
| Square taper washer | DIN 434 (8 %, U-sections) / DIN 435 (14 %, I-sections) | brings a bolt square to a sloping flange | M6–M36 | 304, black steel |
| Spherical and conical seat washers | DIN 6319 (C / D / G) | self-aligning seat for a bolt at an angle | M3–M24 | 304, black steel |
| Tab lock washers | DIN 93 (one tab), DIN 432 (external tab), DIN 463 (two tabs) | mechanical locking by a bent tab | M5–M60 | black and plain steel |
| Multi-tab (KM-nut) lock washer | DIN 5406 (MB) | locks a bearing lock nut | M10–M60 | black steel |
| Bonded sealing washer | maker series | seal under a hex head; roofing | 5.5–16 mm | 304 or zinc steel with EPDM |
| Bonded seal (Dowty washer) | maker series | seals a parallel BSP thread at the port face | G1/8–G2 | stainless steel with EPDM |
| Copper and aluminium sealing rings | DIN 7603 | seal on drain plugs and banjo bolts | M5–M36 | annealed copper, aluminium, fibre |
| Cup (finishing) washer | maker series | countersunk screw on a soft face | M3–M6; anodised aluminium M2–M8 | 304, brass, anodised aluminium |
| Earthing (grounding) washer | maker series | cuts through paint for an earth bond | M4–M20 | zinc and yellow-zinc steel, 304 |
| Insulating washers | — | electrical isolation | M1.2–M24 | nylon, PVC, PTFE, PEEK, fibre, mica, ceramic, see plastic fasteners |
| Saddle (curved) washer | maker series | seats a bolt on a tube | D3–D15 | black steel |
Found the washer type, but not in your size? EKINSUN is a custom parts manufacturer: we make that washer to your drawing, sketch or sample, steel, 304 or 316L stainless steel, brass or plastics, from 1 piece, quoted in 12 hours and shipped duties paid. Already a catalogue size? Ask us too, we may have it in stock, and larger quantities cost less per piece. All custom fasteners
Which washers lock, and which only look like it
Under a correctly preloaded bolt only three washers actually lock: the wedge-lock pair DIN 25201 by cam action, tooth and serrated washers DIN 6797 / 6798 by biting into bare steel, and tab washers DIN 93 / 432 / 463 by a bent tab; a spring washer DIN 127 flattens and adds no locking, and a disc spring DIN 2093 keeps the joint tight but does not lock it.
| Washer | Under a correctly preloaded bolt | Verdict |
|---|---|---|
| Spring (split) washer DIN 127 | flattens; adds no locking; can help take up settling in soft joints | not a lock |
| Tooth and serrated washers DIN 6797 / 6798 | teeth bite the faces and resist rotation; damage coatings and soft aluminium 6061 | locks on bare steel; wrong on painted or soft faces |
| Wedge-lock pair DIN 25201 | cams increase clamp when the bolt tries to turn | locks; the standard answer for vibration |
| Tab washer DIN 93 / 432 / 463 | a bent tab stops the nut turning | locks mechanically; single use |
| Disc spring DIN 2093 | keeps preload when the joint settles or expands with heat | not a lock; keeps the joint tight |
| Wave washer DIN 137 | light axial spring; takes up play | not a lock |
| Nyloc or all-metal lock nut | prevailing torque in the nut itself | locks; see flange and lock nuts |
The rule: a washer chosen to lock a vibrating joint is a wedge-lock pair, a tab washer or a serrated washer on bare metal; everything else is load spreading or spring take-up. The torque chart gives the preload that makes most joints hold without any lock washer at all.
What to send for a washer that is not standard
- Bore, outside diameter and thickness, three numbers; the thread size alone is not enough for a custom washer.
- Flat, spring, tooth, wedge-lock, tab, sealing or spherical, and the job it does.
- Material: 304, 316L, spring steel, copper, brass, aluminium 6061, PEEK, PTFE, nylon.
- Hardness or finish if the washer sits under a 10.9 bolt or on a soft face.
- Quantity: one thick stainless washer or ten thousand stamped ones are both normal.
Stamped or machined? A flat washer in a standard size and thickness is stamped and costs cents. A thick, wide, hardened or odd-bore washer is turned or cut, and the custom washers page explains where the line falls.
Where the washer catalogue stops
Any flat, spring, tooth, serrated, wave, square or sealing washer inside the size ranges above, and wedge-lock pairs M3–M42, disc springs M3–M40 and tab washers M5–M60, are catalogue parts; a washer with a bore, outside diameter or thickness no table pairs, a large or thick washer in 316L, brass, copper or aluminium, a hardened washer for a 10.9 or 12.9 bolt outside the catalogue sizes, or a D-shaped, slotted or keyed washer is made from 1 piece.
| What you need | In the catalogue? | What we make |
|---|---|---|
| Flat, spring, tooth, serrated, wave, square or sealing washer in the size range, standard thickness | Yes | Buy it from stock, or have it made to order from 1 piece. No one-off competes with a stamped washer. Standard parts: ask us too, we may have them in stock. |
| Wedge-lock pairs M3–M42, disc springs M3–M40, tab washers M5–M60 | Yes | Standard sizes: buy them off the shelf, or have them made to order from 1 piece. Standard parts: ask us too, we may have them in stock. |
| A flat washer with a bore, outside diameter or thickness no table pairs | No | Turned from bar or cut from plate, from 1 piece, see custom washers. |
| A large-OD or thick washer in 316L, brass, copper, aluminium 6061 or 7075, PEEK or PTFE | No | Machined in the material named. |
| A hardened washer for a 10.9 or 12.9 bolt in a size the catalogues do not carry | No | Machined from alloy steel and hardened; zinc-flake or black finish. |
| A tab washer, spherical seat or taper washer for a specific nut, angle or flange | No | Machined; tab, seat or taper to the drawing. |
| A sealing washer with a bonded elastomer in an odd size, or a copper ring above M36 | No | Cut or turned; elastomer bonded per batch. |
| A stamped washer of a special shape: D-shape, slotted, keyed, two-hole | No | Stamped to drawing, see custom stamped parts. |
Materials
Standard washers are 304 stainless, zinc-plated or black carbon steel and 65Mn spring steel; sealing rings are annealed copper, aluminium or fibre; machined and thick washers are turned from 303 or 316L, from 42CrMo4 hardened for 10.9 and 12.9 bolts, from brass, aluminium 6061 or 7075, or from nylon, PEEK and PTFE for insulation.
| Material | Designation | Where it fits here |
|---|---|---|
| Stainless 304 | 1.4301 / A2 | the standard washer in every type |
| Stainless 316L | 1.4404 / A4 | standard in the common flat sizes; machined above |
| Free-machining stainless | 303 / 1.4305 | turned thick washers |
| Spring steel | 65Mn, C67S, C75S | spring, wave, disc and wedge-lock washers; zinc, zinc-flake or black |
| Carbon steel | zinc, yellow-zinc, black, nickel, hot-dip | standard steel washers |
| Hardened alloy steel | 42CrMo4 / 1.7225 | washers under 10.9 and 12.9 bolts |
| Copper, aluminium, fibre | Cu-ETP, Al, vulcanised fibre | sealing rings DIN 7603 |
| Brass, phosphor bronze | CW614N, CuSn6 | electrical washers; non-magnetic spring washers |
| Aluminium 6061 | AlMg1SiCu | light flat washers M5–M24; the face a serrated washer must not bite |
| Aluminium 7075 | AlZn5.5MgCu | anodised cup and finishing washers M2–M8 |
| Nylon, PEEK, PTFE | PA66, PEEK, PTFE | insulating washers |
Related pages
- the nut, bolt, washer and pin chart, all families with standard and size range
- Custom washers: machined washers: thick, large-OD, non-standard
- Machined washers from a sketch, how a washer is ordered without a drawing
- combination screw assemblies, washers captive on screws
- the nut with its washer built in, the nut with its washer built in
- Bearing lock nuts, KM nuts and MB tab washers
- Metric bolt torque chart, preload instead of lock washers
- insulating screws, nuts and washers, insulating washers
DIN 433, DIN 125-A and DIN 9021 side by side for M3 to M8, matched to the DIN 912 head they sit under: screws with washer and pre-applied threadlocker.
Frequently asked questions
Barely. Under a properly preloaded bolt a DIN 127 split washer is flat and adds no locking; it can help take up settling in soft or gasketed joints. For a vibrating joint use a wedge-lock pair, a serrated washer on bare metal, a tab washer or a prevailing-torque nut.
DIN 125 (ISO 7089) is the standard flat washer with an outside diameter about twice the bolt size; DIN 9021 (ISO 7093) is the large or fender washer with roughly three times the bolt size, for thin sheet, slots and timber. DIN 433 is the small washer for socket cap screws.
A plain flat washer, or a flange nut with a plain flange. Tooth and serrated washers bite into the face; on aluminium 6061 they embed and the preload relaxes, and on paint they start corrosion.
Yes. Any bore, outside diameter and thickness is turned from bar or cut from plate in 304, 316L, alloy steel, copper, brass, aluminium, PEEK or PTFE, from 1 piece.
EKINSUN is a custom parts manufacturer that machines and stamps washers to any bore, outside diameter, thickness, shape and material, from 1 piece, with a quote within 12 hours.
No list price. Standard sizes are stamped and cost cents; a custom washer is priced by material, section and quantity. A thick 316L washer turned from bar is a few minutes of lathe time; ten thousand stamped D-shape washers are a die plus press time. The quote separates the two.
Send the three numbers
Bore, outside diameter, thickness, the washer type and its job, material, quantity. A photo of the old washer on a rule works. From 1 piece, quote within 12 hours.