DIN 7971 Tapping Screws, Slotted Pan Head
DIN 7971 slotted pan head tapping screws, ST 2.2 to ST 6.3: thread pitch, head and recess geometry, form C/F point reference and the commercial length ladder to 38 mm.
Last updated: 2026-11
Specifications
DIN 7971 is the classic slotted pan head sheet-metal screw — the withdrawn source page tabulates ST 2.2 to ST 6.3 with thread pitch P (0.45 at ST2.2 to 1.8 at ST6.3), head diameter dk max/min (12.5/12.07 at ST6.3), head height k max/min, slot depth t max/min and slot width n — plus the Y columns for the thread-forming (form C) and cutting (form F) point references. The commercial length ladder runs 4.5 to 38 mm. The pan head gives the largest bearing diameter of the slotted heads for thin sheet, and the form split matters at order time: form C forms its thread in the hole (standard sheet-metal duty), form F cuts (for thicker or brittle material). The registered ISO equivalents (ISO 1481 slotted pan head tapping screws and siblings) carry the same duty for new drawings; DIN 7971 keeps legacy bills of material supplied.
| Standard / scope | DIN 7971 tapping screws, slotted pan head — ST 2.2 to ST 6.3, withdrawn (source label) |
|---|---|
| Thread P | Pitch per size, read from the grid (P = 1.8 at ST 6.3; per-size values in the table below) |
| Head / slot | dk max/min 12.5/12.07 at ST 6.3 (pan head); k max/min 3.65/3.3; slot t max/min 2.2/1.8, n max 1.91 |
| Point form | Y columns reference form C (thread-forming) and form F (thread-cutting) values per size |
| Commercial lengths l | Ladder 4.5 to 38 mm; approximate mass per 1000 pcs (ρ=7,85 kg/dm³) tabulated |
| Not tabulated | Case hardness, finish, drilling capacity — per RFQ |
Materials
- Tapping screws order case-hardened steel (the thread-forming duty demands surface hardness over a tough core), zinc-plated as standard, with A2/A4 stainless for corrosion at reduced driving torque. State form C or F, sheet thickness stack and hole/prep size on the RFQ — the collected tables carry head and thread geometry, not the joint data
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 7971 Tapping Screws, Slotted Pan Head) 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
Which lengths of the ladder apply to my sheet stack?
The rule the tables support but do not state: the thread must engage through the last sheet with a couple of full pitches past it, and the unthreaded point may not protrude where it can catch. So measure the total stack, add 2–3 mm, and read the ladder from below — a 2 mm single sheet takes l 6.5, a two-sheet 4 mm stack takes l 9.5, and so on up the printed steps. Overshooting length on tapping screws does not add strength, it adds protrusion and driving torque; undershooting leaves the joint held by fewer pitches than the strip was designed for. When in doubt send the stack on the RFQ and we size it against the standard.
Form C or form F — and why does the table carry both Y columns?
Form C is the ordinary thread-forming screw: its point swages the hole material into a mating thread, best in ductile sheet up to moderate thickness. Form F carries a cutting edge that machines its thread — the choice for thicker stacks, brittle material or repeated reassembly, where forming would torque out or gall. The two Y columns in the collected grid carry the per-size point geometry references for both forms, which is why the source prints them side by side. If your drawing does not name a form, name the material and thickness on the RFQ and we will pick the form that drives at the specified torque and survives the service reassembly count.
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