DIN 7991 Countersunk Socket Head Cap Screws
Hexagon socket countersunk head cap screws per DIN 7991 — current norm DIN EN ISO 10642 — M3 to M24 in steel classes 8.8/10.9/12.9 or A2/A4 stainless, thread 6g. The flush-head socket screw for countersunk, boss-level fastening.
Last updated: 2026-11
Specifications
The countersunk socket head cap screw disappears into the part: a 90° conical head seated in a countersink leaves the surface flush, while the internal hexagon still takes the high torque that keeps socket screws the choice where clamp load matters. The collected standard table runs M3 through M24 in steel property classes 8.8, 10.9 and 12.9 or A2/A4 stainless, thread tolerance 6g. At M10 the head seats at 20 mm maximum diameter with a 5.5 mm head height, a 6 mm hex socket and a 4.4 mm key engagement — proportions that suit bosses, mold cavities and fixture plates where a protruding head would foul the stroke. The DIN 7991 designation is superseded by DIN EN ISO 10642; order whichever your drawing calls out. Note the countersink is part of the purchase decision: the head angle and the flush seating depend on the mating countersink being cut to match.
| Standard | DIN 7991 — hexagon socket countersunk head cap screw; current norm DIN EN ISO 10642 |
|---|---|
| Size range | M3 – M24 |
| Dimensions at M10 | dk (head diameter) nominal=max 20 mm (min 19.48 mm); k (head height) max 5.5 mm; s (hex socket) nominal 6 mm; t (key engagement) nominal=max 4.4 mm; e min 6.86 mm; P (pitch) 1.5 mm |
| Thread | 6g |
| Strength classes | Steel 8.8, 10.9, 12.9; stainless A2, A4 |
Materials
- Steel
- Alloy steel
- Stainless steel
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 7991 Countersunk Socket 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
DIN 7991 and ISO 10642 — which designation should I order?
They cover the same screw: the collected standard table states DIN 7991's current norm is DIN EN ISO 10642, with ISO 10642 listed as the equivalent norm. The practical selection rule is the drawing: order the designation your documentation calls out and confirm thread size, length and strength class against the order. What you should check separately is the countersink — the flush finish this screw exists for depends on the mating 90° seat, so confirm the counterbore spec together with the screw.
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.
What should an RFQ for these screws state?
State the standard designation (for example DIN 7991, DIN 916 or DIN 7985 — or the ISO designation your drawing prints), thread size and pitch, length or head dimension, strength class or material (such as 12.9, 45H, 4.8, A2-70, A4-80 or brass), finish (black oxide, zinc plated, or plain), required certificates such as a mill test report per EN 10204 3.1, and quantity per size — plus destination country.
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