DIN 6340 Washers for Clamping Devices
DIN 6340 washers for clamping devices, M6 to M30 — the hardened, wide-body washer used under clamp screws and T-bolts in fixtures — with the full collected 8-size table: bore, outside diameter and thickness.
Last updated: 2026-11
Specifications
DIN 6340 is the washer sized for workholding: fixture clamps, T-bolts in machine tables, and swing clamps all put a hard, concentrated clamp load through a screw into the part being held. This washer is the interface — wider and thicker than a standard plain washer at the same thread, so it spreads the clamp without deforming, and made to take repeated re-clamping cycle after cycle. The collected table covers M6 to M30 with the bore d (min = nominal size (H14) / max), outside diameter d c (max = nominal size (h14) / min), and thickness h — the three figures a fixture builder needs to match the washer to the clamp stud and the strap. Hardness, materials and finishes are not printed by the collected specification and stay per RFQ. For the companion nut side of the fixture kit see T-slot nuts DIN 508 on this site.
| Standard | DIN 6340 — washers for clamping devices (fixture and workholding washers) |
|---|---|
| Series | M6 – M30 (8 sizes tabulated) |
| Tabulated geometry | Per size: bore d (min=nominal size (H14) / max), outside diameter d c (max=nominal size (h14) / min), thickness h |
| Function | Wide, thick bearing interface under clamp screws and T-bolts — spreads fixture clamp load, survives re-clamping |
| Family note | Pairs with DIN 508 T-slot nuts in the machine-table clamping kit |
| Materials / hardness | Not tabulated by the collected specification — per RFQ (hardness class per application) |
| For thread diameter | d — min=nominal size (H14) | d — max | d c — max=nominal size (h14) | d c — min | h | per 1000 units ≈ kg |
|---|---|---|---|---|---|---|
| M6 | 6.4 | 6.76 | 17 | 16.57 | 3 | 4.6 |
| M8 | 8.4 | 8.76 | 23 | 22.48 | 4 | 11.3 |
| M10 | 10.5 | 10.93 | 28 | 27.48 | 4 | 16.6 |
| M12 | 13 | 13.43 | 35 | 34.38 | 5 | 32.5 |
| M16 | 17 | 17.43 | 45 | 44.38 | 6 | 64.3 |
| M20 | 21 | 21.52 | 50 | 49.38 | 6 | 76 |
| M24 | 25 | 25.52 | 60 | 59.26 | 8 | 147 |
| M30 | 31 | 31.62 | 68 | 67.26 | 10 | 226 |
Materials
- Material and hardness specified per RFQ — the collected specification table covers geometry 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 6340 Washers for Clamping Devices) 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
Why not use a standard plain washer under a fixture clamp?
Because a clamp screw is a much harsher customer than a bolted joint. Fixture clamps are torqued hard, released, and torqued again all day; a thin DIN 125 washer cups under the point load and then cracks or drills into the strap. DIN 6340 adds thickness at the same thread size for section, and outside diameter for spread, so the clamp load stays distributed through thousands of cycles. The tabulated h thickness is the give-away — it runs several times a plain washer's at the same M size. Specify hardness at RFQ when the clamp load or strap material demands it.
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. Common sizes are widely stocked; 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