ISO 10642 Hex Socket Countersunk Head Cap Screws
ISO 10642 countersunk head cap screws with hexagon socket, M3 to M20 — the high-strength socket-drive countersunk screw that replaces DIN 7991 — with the full collected 10-size table: head-cone geometry, socket width limits, engagement depth, per-class minimum tensile loads and the thread-length ladder.
Last updated: 2026-11
Specifications
ISO 10642 is the countersunk counterpart of the socket cap screw family: a 90-degree countersunk flat head carrying a hexagon socket instead of a slot or cross recess, sized and strength-rated for structural-grade machine work. The collected page maps it to DIN 7991, the designation it replaces, and — uniquely in this countersunk batch — the collected table carries strength data as well as geometry: minimum tensile loads printed per size for property classes 8.8, 10.9 and 12.9. That combination is the design intent. A countersunk seat has less metal under the head than a flanged cap head, so the joint lives or dies on the screw's tensile rating, not on bearing area; pairing the cone geometry with explicit 10.9/12.9 tensile columns makes ISO 10642 the countersunk head you can actually load like a cap screw — jig bodies, mould bases, machine tool fixtures — while still sitting flush. The table runs M3 to M20 (M14 in brackets) across three block tables and tabulates: theoretical d k max and actual d k min, shank d s with max/min limits, the e minimum across-corners of the socket, head height k max, socket width s as Nominal / max / min, the t minimum socket engagement depth, the three per-class minimum tensile loads in newtons, and the thread length b ladder in three length regimes (L up to 125 mm, 125 to 200 mm, over 200 mm) printed per size. The countersink itself follows DIN 74 form A, as the collected page notes. Finishes are not printed by the collected specification and follow the drawing callout.
| Standard | ISO 10642 — countersunk head cap screws with hexagon socket (collected page notes it replaces DIN 7991; countersink per DIN 74 form A) |
|---|---|
| Series | M3 – M20 (10 sizes across three block tables; M14 in brackets) |
| Tabulated geometry | Per size: pitch P, head diameter d k theoretical max / actual min, shank d s max/min, socket across-corners e min, head height k max, socket width s (Nominal / max / min), engagement depth t min, thread length b per length regime |
| Dimensions at M6 | d k theoretical max 13.44 / actual min 11.34; d s max 6 / min 5.82; e min 4.583; k max 3.72; s nominal 4 (max 4.095 / min 4.02); t min 2.2; b 18 (L≤125), 24 (125–200) |
| Dimensions at M12 | d k theoretical max 26.88 / actual min 23.12; d s max 12 / min 11.73; e min 9.149; k max 7.44; s nominal 8 (max 8.175 / min 8.025); t min 4.3; b 30 (L≤125), 36 (125–200), 49 (L>200) |
| Dimensions at M20 | d k theoretical max 40.32 / actual min 36.05; d s max 20 / min 19.67; e min 13.716; k max 10.16; s nominal 12 (max 12.212 / min 12.032); t min 5.6; b 46 (L≤125), 52 (125–200), 65 (L>200) |
| Minimum tensile load at M6 | 8.8: 12900 N; 10.9: 16700 N; 12.9: 19600 N (per collected table) |
| Minimum tensile load at M12 | 8.8: 53900 N; 10.9: 70200 N; 12.9: 82400 N (per collected table) |
| Minimum tensile load at M20 | 8.8: 162000 N; 10.9: 204000 N; 12.9: 239000 N (per collected table) |
| Finishes | Not tabulated by the collected specification — per RFQ (finish per drawing callout) |
| Nominal Size | Body Dia. D Max | Body Dia. D Min | Pitch P (mm) | Hex Socket J | Max Cone Dia. A1 | Head Dia. A Max | Head Dia. A Min | Head Height H | Socket Depth K |
|---|---|---|---|---|---|---|---|---|---|
| M3 | 3.00 | 2.86 | 0.5 | 2.0 | 6.72 | 6.00 | 5.82 | 1.86 | 1.05 |
| M4 | 4.00 | 3.82 | 0.7 | 2.5 | 8.96 | 8.00 | 7.78 | 2.48 | 1.49 |
| M5 | 5.00 | 4.82 | 0.8 | 3.0 | 11.20 | 10.00 | 9.78 | 3.10 | 1.86 |
| M6 | 6.00 | 5.82 | 1.0 | 4.0 | 13.44 | 12.00 | 11.75 | 3.72 | 2.16 |
| M8 | 8.00 | 7.78 | 1.25 | 5.0 | 17.92 | 16.00 | 15.73 | 4.96 | 2.85 |
| M10 | 10.00 | 9.78 | 1.5 | 6.0 | 22.40 | 20.00 | 19.67 | 6.20 | 3.60 |
| M12 | 12.00 | 11.73 | 1.75 | 8.0 | 26.88 | 24.00 | 23.67 | 7.44 | 4.35 |
| M16 | 16.00 | 15.73 | 2.0 | 10.0 | 33.60 | 32.00 | 29.67 | 8.80 | 4.89 |
| M20 | 20.00 | 19.67 | 2.5 | 10.0 | 40.32 | 40.00 | 35.61 | 10.16 | 5.49 |
Materials
- Steel per property class 8.8 / 10.9 / 12.9 (strength tabulated); finish specified per RFQ
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 (ISO 10642 Hex Socket Countersunk Head Cap Screws) 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 does the countersunk head need a per-class tensile table at all?
Because seating geometry removes the usual margin. A hex socket cap screw (ISO 4762) seats on its cylindrical head wall, so the joint capacity is mostly the bolt's cross-section; a countersunk head wedges into the cone, and part of the clamp travels into the part as radial force on the countersink rim. When the screw is loaded in tension, the failure path is the screw itself — which is why the collected table prints minimum tensile loads per class: at M12, 12.9 delivers 82400 N against 53900 N at 8.8, so the class choice scales directly. The design consequence: use ISO 10642 in high class where the flush seat is functionally required, size the countersink to DIN 74 form A, and never assume a countersunk screw carries like the cap screw of the same thread without checking the printed load.
The b column has three regimes — which thread length applies to my part?
The collected table splits the thread-length ladder by grip length: for screws with nominal length L up to 125 mm the first row applies (18 at M6, 30 at M12, 46 at M20); from 125 to 200 mm the second row (24, 36, 52); over 200 mm the third (only the larger sizes, e.g. 45 at M10 and 49 at M12). The regime exists because longer screws carry a defined non-threaded shank portion, and the tabulated b is the minimum thread that must remain. For a drawing with a nonstandard grip, state the length explicitly at quotation and we confirm the resulting thread length against the standard rather than interpolating the ladder.
What is the MOQ and lead time for these screws?
Minimum order quantity is 10,000 pieces per item. Stocked sizes ship in 3–7 days; non-stock diameters, lengths or finishes are quoted with a confirmed schedule. Common sizes in this designation are widely stocked — confirm the exact schedule against quantity and size mix at quotation.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
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