DIN 6319 Spherical Washers (Form C) and Conical Seat Washers (Form D)
Spherical washer assemblies per DIN 6319 — Form C spherical (convex) washers paired with Form D conical (concave) seat washers. The ball seat lets a bolt head or nut swivel to meet a joint face that is not square to the thread axis; the collected tables run M6–M48 for both forms.
Last updated: 2026-11
Specifications
DIN 6319 is a two-piece bearing: Form C is a washer with a convex spherical top face, Form D is its mating washer with a concave conical seat. Placed as a pair under a bolt head or a nut, the convex surface rocks inside the concave one, so the fastener can tilt to whatever angle the joint face actually sits at while the thread axis stays loaded in pure tension. That is the fix for the classic misalignment problem: when a bolt meets a face that is not square to its axis — rough sawn surfaces, cast faces, angled lugs — the edge of an ordinary washer carries the preload on one side and the bolt bends. With a 6319 pair the contact stays central, and the loaded shank sees tension only. The two forms are ordered together: the collected tables give per-size hole, outer diameter, thickness and (Form C) ball radius SR from M6 to M48, with the mating seat geometry in the same size row. Selection is by the mating pair, not by either piece alone.
| Standard | DIN 6319 — spherical washers Form C and mating conical seat washers Form D (ordered as a pair) |
|---|---|
| Function | Ball seat lets the fastener swivel to meet a face not square to the thread axis; preload stays central and the bolt shank carries tension, not bending |
| Form C size range | M6 through M48 — hole d (tol. H13) 6.4–50 mm, OD dc 12–92 mm, ball radius SR 9–67 mm |
| Form D size range | M6 through M48 — hole d (tol. H13) 7.1–56 mm, OD dc 12–92 mm, seat diameter d1 11–82 mm |
| Typical applications | Angled or rough joint faces: lugs, clevis ends, cast or sawn faces, machine feet — anywhere the bearing face cannot be machined square |
| Nominal thread | Hole d min (= nominal, tol. H13) (mm) | Hole d max (mm) | OD dc (mm) | Thickness h (mm) | Chamfer f ≈ (mm) | h1 (mm) | SR (mm) | Weight ≈ (kg / 100 pcs) |
|---|---|---|---|---|---|---|---|---|
| M6 | 6.4 | 6.62 | 12 | 2.3 | 0.3 | 0.7 | 9 | 0.09 |
| M8 | 8.4 | 8.62 | 17 | 3.2 | 0.5 | 0.6 | 12 | 0.25 |
| M10 | 10.5 | 10.77 | 21 | 4 | 0.5 | 0.8 | 15 | 0.47 |
| M12 | 13 | 13.27 | 24 | 4.6 | 0.5 | 1.1 | 17 | 0.71 |
| M14 | 15 | 15.27 | 28 | 5 | 0.5 | 1.2 | 22 | 1 |
| M16 | 17 | 17.27 | 30 | 5.3 | 0.5 | 1.3 | 22 | 1.23 |
| M20 | 21 | 21.33 | 36 | 6.3 | 0.5 | 2 | 27 | 2.08 |
| M24 | 25 | 25.33 | 44 | 8.2 | 0.8 | 2.4 | 32 | 4.2 |
| M30 | 31 | 31.39 | 56 | 11.2 | 0.8 | 3.6 | 41 | 8.7 |
| M36 | 37 | 37.39 | 68 | 14 | 1 | 4.6 | 50 | 18.4 |
| M42 | 43 | 43.39 | 78 | 17 | 1 | 6.5 | 58 | 29.7 |
| M48 | 50 | 50.39 | 92 | 21 | 1 | 8 | 67 | 52.5 |
| Nominal thread | Hole d min (= nominal, tol. H13) (mm) | Hole d max (mm) | OD dc (mm) | d1 (mm) | Thickness h (mm) | Weight ≈ (kg / 100 pcs) |
|---|---|---|---|---|---|---|
| M6 | 7.1 | 7.32 | 12 | 11 | 2.8 | 0.14 |
| M8 | 9.6 | 9.82 | 17 | 14.5 | 3.5 | 0.38 |
| M10 | 12 | 12.27 | 21 | 18.5 | 4.2 | 0.65 |
| M12 | 14.2 | 14.47 | 24 | 20 | 5 | 1.06 |
| M14 | 16.5 | 16.77 | 28 | 24.8 | 5.6 | 1.8 |
| M16 | 19 | 19.33 | 30 | 26 | 6.2 | 1.87 |
| M20 | 23.2 | 23.53 | 36 | 31 | 7.5 | 3.2 |
| M24 | 28 | 28.33 | 44 | 37 | 9.5 | 6.3 |
| M30 | 35 | 35.39 | 56 | 49 | 12 | 13.3 |
| M36 | 42 | 42.39 | 68 | 60 | 15 | 23.6 |
| M42 | 49 | 49.39 | 78 | 70 | 18 | 36.5 |
| M48 | 56 | 56.46 | 92 | 82 | 22 | 64.1 |
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 6319 Spherical Washers (Form C) and Conical Seat Washers (Form D)) 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 order Form C and Form D together?
Because the pair is the assembly. Form C carries the convex spherical face that the fastener bears on, and Form D carries the matching concave seat it rocks in; on their own neither piece corrects anything. The tables below are row-aligned by thread size so a matched set is read off one line — hole and outer diameter of each piece, the ball radius SR of the Form C and the seat diameter d1 of the Form D. Quote both forms at the same nominal thread size on the RFQ.
When is a ball-seat washer the right fix for misalignment?
When the face cannot be made square. A machined flat face needs no help; but on an angled lug, a cast pad, a sawn beam end or a weldment where the contact face sits at an unknown angle, an ordinary washer loads on one edge and bends the bolt. The DIN 6319 pair lets the bearing surface rotate to the face while the thread axis stays straight, so the bolt works in tension as designed. Note the limit: the pair corrects tilt of the bearing plane — it does not correct a misaligned hole, and it adds stack height, so the fastener length must include both washers.
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