DIN 963 Slotted Countersunk Machine Screws
Slotted countersunk head screws per DIN 963 — current norm DIN EN ISO 2009 — M1 to M20 in steel class 4.8, A2/A4 stainless, brass or plastic, thread 6g. The flush-head machine screw for slotted-driver tooling and fine instrument work.
Last updated: 2026-11
Specifications
The slotted countersunk machine screw is the oldest flush fastener still in volume service: a 90° conical head with a single slot, seated flush in a prepared countersink and driven by a flat-blade screwdriver. The collected standard table runs M1 through M20 — the widest thread span of the machine-screw family, reaching down to M1 for instrument work — in steel class 4.8, A2/A4 stainless, brass or plastic (Pa), thread tolerance 6g. At M4 the head seats at 7.5 mm maximum diameter with a 2.2 mm head height and a 0.8 mm slot; at M5 the seat grows to 9.2 mm with a 2.5 mm height. DIN 963's current norm is DIN EN ISO 2009. Choose it where the driver infrastructure is slotted — watchmaker and instrument assemblies, restoration work, electrical terminals — and accept its known limit: the slot gives the driver no centring, so it is not the fastener for torque-critical or high-speed driven joints; the cross recessed counterpart is DIN 965/ISO 7046.
| Standard | DIN 963 — slotted countersunk head screw; current norm DIN EN ISO 2009 |
|---|---|
| Size range | M1 – M20 |
| Dimensions at M4 | dk (head diameter) nominal=max 7.5 mm (min 7.14 mm); k (head height) max 2.2 mm; n (slot width) nominal 0.8 mm (max 0.96 mm); P 0.7 mm |
| Dimensions at M5 | dk nominal=max 9.2 mm (min 8.84 mm); k max 2.5 mm; n nominal 1.2 mm |
| Strength / materials | Steel 4.8; stainless A2, A4; brass; plastic (Pa) |
| Thread | 6g |
Materials
- Steel
- Stainless steel
- Brass
- Plastic
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 963 Slotted Countersunk Machine 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
Slotted or cross recessed countersunk — where does the slot still make sense?
Where the screw is set once by hand and looked at afterwards. The slot is serviceable with any flat blade, survives cleaning and refinishing, and is the traditional callout in instruments, electrical terminals, optical mounts and restoration work — and the M1–M20 span of the collected DIN 963 table reaches sizes the cross recessed lines do not. The costs are torque and speed: a blade cams out of the slot under load and cannot centre itself, so production lines that drive screws automatically specify the cross recessed equivalents (DIN 965 / ISO 7046 for countersunk, DIN 7985 / ISO 7045 for pan head) instead.
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 914, DIN 915, DIN 7981/7982/7983 — or the ISO designation your drawing prints), thread or tapping size, length or head dimension, strength class or material (such as 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