DIN 137 Spring Washers (Form A Curved / Form B Waved)
Spring washers per DIN 137 in both forms — Form A curved (single arc) and Form B waved (two arcs). The arc geometry gives a controlled spring deflection that keeps residual tension on a lightly loaded fastener after it relaxes; the collected tables run Form A M1–M10 and Form B M3–M36.
Last updated: 2026-11
Specifications
DIN 137 spring washers are flat washers formed into a shallow arc — one arc in Form A, a wave of two arcs in Form B. Under the bolt or screw head the arc acts as a spring: when the joint embeds or the fastener loosens slightly through thermal cycling or micro-settlement, the washer legs compress and keep pressing the head, so residual clamp is maintained where a flat washer alone would go slack. They are light-tension devices, not vibration locks — a curved or waved washer does not bite the joint the way a toothed washer or a wedge-locking pair does, so it belongs on assemblies where the load is light and the enemy is relaxation rather than rotation: sheet-metal covers, electrical hardware, small housings. Form A suits the smallest screws (the collected table starts at M1); Form B covers the wider series from M3 up to M36 with thickness growing stepwise across the range. Both forms are quoted with per-size hole, outer-diameter, thickness and free-height data in the tables below.
| Standard | DIN 137 — spring washers: Form A (curved, single arc), Form B (waved, two arcs) |
|---|---|
| Form A size range | M1 through M10 — hole d 1.1–8.4 mm, OD dc 2.5–15 mm, thickness h 0.2–0.5 mm |
| Form B size range | M3 through M36 — hole d 3.2–37 mm, OD dc 8–68 mm, thickness h 0.5–2.5 mm |
| Spring deflection | Free height H minus flat thickness h gives the available compression per size (both H min/max tabulated per size below) |
| Locking character | Spring action only — maintains residual tension under relaxation; not a positive or friction lock against rotation |
| Nominal thread | Hole d min (= nominal) (mm) | Hole d max (mm) | OD dc nominal (mm) | OD dc max (mm) | OD dc min (mm) | Thickness h nominal (mm) | Thickness h max (mm) | Thickness h min (mm) | Free height H min (mm) | Free height H max (mm) | Weight ≈ (kg / 1000 pcs) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| M1 | 1.1 | 1.35 | 2.5 | 2.8 | 2.2 | 0.2 | 0.22 | 0.18 | 0.35 | 0.7 | 0.006 |
| M1.2 | 1.3 | 1.55 | 3 | 3.3 | 2.7 | 0.2 | 0.22 | 0.18 | 0.35 | 0.7 | 0.009 |
| M1.4 | 1.5 | 1.75 | 3 | 3.3 | 2.7 | 0.25 | 0.27 | 0.23 | 0.4 | 0.8 | 0.01 |
| M1.7 | 1.8 | 2.05 | 4 | 4.375 | 3.625 | 0.25 | 0.27 | 0.23 | 0.45 | 0.9 | 0.02 |
| M1.8 | 1.9 | 2.15 | 4 | 4.375 | 3.625 | 0.25 | 0.27 | 0.23 | 0.45 | 0.9 | 0.02 |
| M2 | 2.2 | 2.45 | 4.5 | 4.875 | 4.125 | 0.3 | 0.33 | 0.27 | 0.5 | 1 | 0.028 |
| M2.3 | 2.5 | 2.75 | 5 | 5.375 | 4.625 | 0.3 | 0.33 | 0.27 | 0.5 | 1 | 0.035 |
| M2.6 | 2.8 | 3.05 | 5.5 | 5.875 | 5.125 | 0.3 | 0.33 | 0.27 | 0.55 | 1.1 | 0.041 |
| M3 | 3.2 | 3.5 | 6 | 6.375 | 5.625 | 0.4 | 0.45 | 0.35 | 0.65 | 1.3 | 0.063 |
| M3.5 | 3.7 | 4 | 7 | 7.45 | 6.55 | 0.4 | 0.45 | 0.35 | 0.7 | 1.4 | 0.088 |
| M4 | 4.3 | 4.6 | 8 | 8.45 | 7.55 | 0.5 | 0.55 | 0.45 | 0.8 | 1.6 | 0.14 |
| M5 | 5.3 | 5.6 | 10 | 10.45 | 9.55 | 0.5 | 0.55 | 0.45 | 0.9 | 1.8 | 0.222 |
| M6 | 6.4 | 6.76 | 11 | 11.55 | 10.45 | 0.5 | 0.55 | 0.45 | 1.1 | 2.2 | 0.247 |
| M7 | 7.4 | 7.76 | 12 | 12.55 | 11.45 | 0.5 | 0.55 | 0.45 | 1.2 | 2.4 | 0.265 |
| M8 | 8.4 | 8.76 | 15 | 15.55 | 14.45 | 0.5 | 0.55 | 0.45 | 1.7 | 3.4 | 0.476 |
| M10 | 10.5 | 10.93 | 18 | 18.55 | 17.45 | 0.8 | 0.86 | 0.74 | 2 | 4 | 1.05 |
| Nominal thread | Hole d min (mm) | Hole d max (mm) | OD dc nominal (mm) | OD dc max (mm) | OD dc min (mm) | Thickness h nominal (mm) | Thickness h max (mm) | Thickness h min (mm) | Free height H max (mm) | Free height H min (mm) | Weight ≈ (kg / 1000 pcs) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| M3 | 3.2 | 3.5 | 8 | 8.45 | 7.55 | 0.5 | 0.55 | 0.45 | 1.6 | 0.8 | 0.166 |
| M3.5 | 3.7 | 4 | 8 | 8.45 | 7.55 | 0.5 | 0.55 | 0.45 | 1.8 | 0.9 | 0.154 |
| M4 | 4.3 | 4.6 | 9 | 9.45 | 8.55 | 0.5 | 0.55 | 0.45 | 2 | 1 | 0.193 |
| M5 | 5.3 | 5.6 | 11 | 11.55 | 10.45 | 0.5 | 0.55 | 0.45 | 2.2 | 1.1 | 0.286 |
| M6 | 6.4 | 6.76 | 12 | 12.55 | 11.45 | 0.5 | 0.55 | 0.45 | 2.6 | 1.3 | 0.318 |
| M7 | 7.4 | 7.76 | 14 | 14.55 | 13.45 | 0.8 | 0.86 | 0.74 | 3 | 1.5 | 0.7 |
| M8 | 8.4 | 8.76 | 15 | 15.55 | 14.45 | 0.8 | 0.86 | 0.74 | 3 | 1.5 | 0.762 |
| M10 | 10.5 | 10.93 | 21 | 21.65 | 20.35 | 1 | 1.07 | 0.93 | 4.2 | 2.1 | 2.04 |
| M12 | 13 | 13.43 | 24 | 24.65 | 23.35 | 1.2 | 1.27 | 1.13 | 5 | 2.5 | 3.01 |
| M14 | 15 | 15.43 | 28 | 28.65 | 27.35 | 1.6 | 1.68 | 1.52 | 6 | 3 | 5.51 |
| M16 | 17 | 17.43 | 30 | 30.65 | 29.35 | 1.6 | 1.68 | 1.52 | 6.4 | 3.2 | 6.03 |
| M18 | 19 | 19.52 | 34 | 34.8 | 33.2 | 1.6 | 1.68 | 1.52 | 6.6 | 3.3 | 7.84 |
| M20 | 21 | 21.52 | 36 | 36.8 | 35.2 | 1.6 | 1.68 | 1.52 | 7.4 | 3.7 | 8.43 |
| M22 | 23 | 23.52 | 40 | 40.8 | 39.2 | 1.8 | 1.9 | 1.7 | 7.8 | 3.9 | 11.9 |
| M24 | 25 | 25.52 | 44 | 44.8 | 43.2 | 1.8 | 1.9 | 1.7 | 8.2 | 4.1 | 14.5 |
| M27 | 28 | 28.52 | 50 | 50.8 | 49.2 | 2 | 2.1 | 1.9 | 9.4 | 4.7 | 21.1 |
| M30 | 31 | 31.62 | 56 | 56.95 | 55.05 | 2.2 | 2.3 | 2.1 | 10 | 5 | 29.5 |
| M33 | 34 | 34.62 | 60 | 60.95 | 59.05 | 2.2 | 2.3 | 2.1 | 10.6 | 5.3 | 33.1 |
| M36 | 37 | 37.62 | 68 | 68.95 | 67.05 | 2.5 | 2.65 | 2.35 | 11.6 | 5.8 | 50.2 |
Materials
- Material and finish specified per RFQ — the collected specification tables cover geometry and unit weights only
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 137 Spring Washers (Form A Curved / Form B Waved)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
When does a DIN 137 washer do the job, and when does it not?
It does the job when the fastener is lightly loaded and the risk is that the joint goes slack — covers, terminals, small housings that see temperature cycling. It does not do the job when rotation is the risk: a curved or waved washer cannot stop a nut turning the way a tab washer, a toothed washer or a wedge-locking pair can, and it holds far less spring force than a disc spring. If the joint is safety-relevant or sees vibration, specify a positive lock instead and treat the DIN 137 washer as a tension-maintaining detail only.
Form A or Form B — how do I choose?
Follow the size first and the geometry second. The collected tables show Form A covering the small series from M1 (where a wave would be impractically fine) up to M10, while Form B starts at M3 and runs to M36. Where both forms exist in your size, the waved Form B presents two contact arcs and a slightly stiffer, more centered deflection, while the curved Form A is the simpler single-arc spring — the per-size free-height data below tells you exactly how much compression each form offers at your size.
What is the MOQ and lead time for this washer type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Confirm the exact schedule against quantity and size mix at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support