ISO 1482 Slotted Countersunk Head Tapping Screws
ISO 1482 slotted countersunk head tapping screws ST2,2 to ST6,3 — the flush-finish sheet-metal screw for pre-countersunk holes, with the collected geometry ladder (dk/k/n/r/t) and the per-length mass ladder.
Last updated: 2026-11
Specifications
ISO 1482 takes the slotted tapping screw flush: a 90-degree countersunk head that sits at or below the sheet surface once the hole is countersunk to match. That flush is the point wherever a sliding workpiece, a wiper, or a second panel passes over the fastener — the head leaves nothing to catch. The collected ladder runs ST2,2 to ST6,3 with the head diameter dk in its nominal=max./min. pair (4,3/4 at ST2,2 up to 12,4/11,97 at ST6,3), the approximate head height k, the slot triple n nominal/min./max., the countersink edge radius r (0,8 → 2,4 — larger than the pan head's, because the edge blends into the countersink cone), and the slot-depth t min./max. pair. The length ladder runs l 6,5 to 38 with Type C/F limits and the source's approximate mass columns per thread. One verbatim print defect is flagged: the slot nominal n at ST4,8 reads 12 against the sibling progression (0,6 → 1,6) — a lost decimal point; read that cell per RFQ if the slot sizing matters. Countersinking discipline: the hole needs both the clearance pilot and the 90-degree cone, cut deep enough that the head seats on the cone, not the edge. Property class, material and finish are not tabulated — per RFQ.
| Standard | ISO 1482 — slotted countersunk head tapping screws |
|---|---|
| Size range | ST2,2 – ST6,3; parenthesised (ST3,9) is the source's non-preferred marking |
| Head diameter | dk nominal=max. 4,3 → 12,4 mm (min. 4 → 11,97) |
| Slot | n nominal 0,6 → 1,6 (ST4,8 cell prints 12 verbatim — flagged); t min. 0,4 → 1,2, max. 0,6 → 1,75 |
| Countersink radius | r max. 0,8 → 2,4 mm per size |
| Length ladder | l 6,5 – 38 with Type C/F min./max. limits and approximate mass per thread |
| Material / finish | Not tabulated by the collected specification — per RFQ |
| Attribute | Limit | ST2,2 | ST2,9 | ST3,5 | (ST3,9) | ST4,2 | ST4,8 | ST5,5 | ST6,3 |
|---|---|---|---|---|---|---|---|---|---|
| P | 0,8 | 1,1 | 1,3 | 1,3 | 1,4 | 1,6 | 1,8 | 1,8 | |
| a | max. | 0,8 | 1,1 | 1,3 | 1,3 | 1,4 | 1,6 | 1,8 | 1,8 |
| dk | nominal=max. | 4,3 | 5,5 | 6,8 | 7,5 | 8,1 | 9,5 | 10,8 | 12,4 |
| dk | min. | 4 | 5,2 | 6,44 | 7,14 | 7,74 | 9,14 | 10,37 | 11,97 |
| k | approx. | 1,3 | 1,7 | 2,1 | 2,3 | 2,5 | 3 | 3,4 | 3,8 |
| n | nominal | 0,6 | 0,8 | 1 | 1 | 1,2 | 12 | 1,6 | 1,6 |
| n | min. | 0,66 | 0,86 | 1,06 | 1,06 | 1,26 | 1,26 | 1,66 | 1,66 |
| n | max. | 0,8 | 1 | 1,2 | 1,2 | 1,51 | 1,51 | 1,91 | 1,91 |
| r | max. | 0,8 | 1,1 | 1,4 | 1,5 | 1,6 | 1,9 | 2,1 | 2,4 |
| t | min. | 0,4 | 0,5 | 0,6 | 0,7 | 0,75 | 0,85 | 1 | 1,2 |
| t | max. | 0,6 | 0,75 | 0,95 | 1,05 | 1,15 | 1,35 | 1,5 | 1,75 |
| y max. | Type C | 2 | 2,6 | 3,2 | 3,5 | 3,7 | 4,3 | 5 | 6 |
| y max. | Type F | 1,6 | 2,1 | 2,5 | 2,7 | 2,8 | 3,2 | 3,6 | 3,6 |
- Row 6 (n): n nominal at ST4,8 prints 12 against the sibling progression 0,6/0,8/1/1/1,2/…/1,6/1,6 — a lost decimal point suspected. Carried verbatim, not normalized.
| l nominal | Type C min. | Type C max. | Type F min. | Type F max. | ST2,2 | ST2,9 | ST3,5 | (ST3,9) | ST4,2 | ST4,8 | ST5,5 | ST6,3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6,5 | 5,7 | 7,3 | 5,7 | 6,5 | 0,14 | 0,242 | ||||||
| 9,5 | 8,7 | 10,3 | 8,7 | 9,5 | 0,2 | 0,35 | 0,548 | 0,658 | 0,775 | 1,1 | ||
| 13 | 12,2 | 13,8 | 12,2 | 13 | 0,27 | 0,476 | 0,722 | 0,88 | 1,02 | 1,45 | 2,11 | 2,53 |
| 16 | 15,2 | 16,8 | 15,2 | 16 | 0,33 | 0,584 | 0,871 | 1,07 | 1,23 | 1,75 | 2,49 | 3,07 |
| 19 | 18,2 | 19,8 | 18,2 | 19 | 0,692 | 1,02 | 1,26 | 1,44 | 2,05 | 2,87 | 3,61 | |
| 22 | 21,2 | 22,8 | 20,7 | 22 | 1,17 | 1,45 | 1,65 | 2,35 | 3,26 | 4,15 | ||
| 25 | 24,2 | 25,8 | 23,7 | 25 | 1,32 | 1,64 | 1,86 | 2,65 | 3,65 | 4,69 | ||
| 32 | 30,7 | 33,3 | 30,7 | 32 | 2,35 | 3,35 | 4,56 | 5,95 | ||||
| 38 | 36,7 | 39,3 | 36,7 | 38 | 3,95 | 5,34 | 7,03 |
Materials
- Material and finish specified per RFQ — state the host sheet thickness (the countersink cone eats into it; thin sheet needs a formed rather than cut countersink) and any plating requirement
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 1482 Slotted Countersunk Head Tapping 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
Countersunk (ISO 1482) or raised countersunk (ISO 1483) — what changes on the sheet?
Nothing about the hole; everything about the surface. Both screws use the same head diameter ladder (dk 4,3 → 12,4 across the shared size range) and the same countersink cone, so the drilled and csk-prepped hole is interchangeable. ISO 1482 finishes flush: nothing above the sheet. ISO 1483 adds the raised crown — the collected f row (approx. 0,7 → 2 mm) — which keeps a screwdriver engaged past paint drips and gives a slightly larger driving bearing, at the cost of a proud button you must recess or accept. The raised member also carries a bigger crown radius rf (3,8 → 11,1 in its ladder vs none on the flush head). Practical read: flush where anything slides over the surface, raised where driving access and paint tolerance matter more than profile. Slot sizing, thread and length ladders otherwise match, and both carry the same verbatim ST4,8 slot-n print defect — per RFQ on that cell. Material, class and finish stay per RFQ on both.
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