ISO 1580 Slotted Pan Head Screws
ISO 1580 slotted pan head screws — M1,6 to M10, the classic flat-topped machine screw with a single slot, with the collected geometry rows and the full weight ladder M1,6–M10 × l 2–80.
Last updated: 2026-11
Specifications
ISO 1580 is the baseline machine screw: a rounded pan head with a single slot, thread M1,6 to M10, and full geometry control — head diameter dk, head height k, slot width n and depth t with their own tolerance windows, run-out X — everything a design needs to specify the simplest head money can buy. The collected data carries the per-thread geometry ladder and a complete kg/1000 weight matrix across nominal lengths 2 to 80 (0,075 g at the smallest up to 52,2 kg per thousand at M10×80), so the page doubles as a costing reference. Slot drives earn their keep where cost, reversibility and hand-tool service beat torque: instrument assemblies, electrical fittings, anything maintained with a flat blade in the field. What they do not survive is production-line torque — cam-out limits the tightening, and that is precisely why the hexalobular pages (ISO 14579 and siblings) exist on the same head outlines. Order by thread and length from the ladder; the (M3,5) column is the source's non-preferred size, and the mixed decimal-point/comma prints and the "(M3,5)3" header token are flagged verbatim, not repaired. Property class (typically 4.8) and finish are not tabulated by the collected specification — per RFQ.
| Standard | ISO 1580 — slotted pan head screws |
|---|---|
| Size range | Threads M1,6 – M10, (M3,5) non-preferred per the source notation |
| Head diameter | dk: nom. = max. / min. per thread (e.g. M4: 8,00 / 7,64 mm) |
| Head height | k: nom. = max. / min. per thread (M4: 2,40 / 2,26 mm) |
| Slot | n nominal 0,4 (M1,6) → 2,5 (M10) mm with max./min. windows; t min. 0,35 → 2,4 mm |
| Thread run-out | a max. and X max. per thread; b min. 25 mm (M1,6–M3) / 38 mm (up from (M3,5)) |
| Weight | kg/1000 pcs ladder, l 2 – 80 × M1,6 – M10, carried verbatim (0,075 → 52,2) |
| Property class / finish | Not tabulated by the collected specification — per RFQ |
| Thread d | P | a max. | b min. | dk nom. = max. | dk min. | da max. | k nom. = max. | k min. | n nom. | n max. | n min. | r min. | rt ref. | t min. | w min. | X max. |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M1.6 | 0,35 | 0,7 | 25 | 3,2 | 2,9 | 2 | 1,00 | 0,86 | 0,4 | 0,60 | 0,46 | 0,1 | 0.5 | 0,35 | 0,3 | 0,9 |
| M2 | 0,4 | 0,8 | 25 | 4,0 | 3,7 | 2,6 | 1,30 | 1,16 | 0,5 | 0,70 | 0,56 | 0,1 | 0,6 | 0,5 | 0,4 | 1 |
| M2,5 | 0,45 | 0,9 | 25 | 5,0 | 4,7 | 3,1 | 1,50 | 1,36 | 0.6 | 0,80 | 0,66 | 0,1 | 0.8 | 0.6 | 0.5 | 1.1 |
| M3 | 0,5 | 1 | 25 | 5,6 | 5,3 | 3,6 | 1,80 | 1,66 | 0,8 | 1,00 | 0,86 | 0,1 | 0,9 | 0,7 | 0,7 | 1,25 |
| (M3,5)3 | 0,6 | 1.2 | 38 | 7,00 | 6,64 | 4,1 | 2,10 | 1,96 | 1 | 1,20 | 1,06 | 0,1 | 1 | 0,8 | 0,8 | 1.5 |
| M4 | 0,7 | 1,4 | 38 | 8,00 | 7,64 | 4.7 | 2,40 | 2,26 | 1.2 | 1,51 | 1,26 | 0,2 | 1.2 | 1 | 1 | 1.75 |
| M5 | 0,8 | 1.6 | 38 | 9,50 | 9,14 | 5,7 | 3,00 | 2,86 | 1.2 | 1,51 | 1,26 | 0.2 | 1.5 | 1.2 | 1.2 | 2 |
| M6 | 1 | 2 | 38 | 12,00 | 11,57 | 6,8 | 3,6 | 3,3 | 1.6 | 1,91 | 1,66 | 0,25 | 1.8 | 1,4 | 1,4 | 2.5 |
| M8 | 1,25 | 2,5 | 38 | 16,00 | 15,57 | 9.2 | 4,8 | 4.5 | 2 | 2,31 | 2,06 | 0,4 | 2,4 | 1.9 | 1.9 | 3.2 |
| M10 | 1.5 | 3 | 38 | 20,00 | 19,48 | 11,2 | 6,0 | 5,7 | 2,5 | 2,81 | 2,56 | 0,4 | 3 | 2,4 | 2,4 | 3,8 |
- Row 5 ((M3,5)3): Thread header token "(M3,5)3" carries a stray trailing 3 in the source. Column = the parenthesised non-preferred (M3,5) size. Carried verbatim.
| l nominal | l min. | l max. | M1.6 | M2 | M2,5 | M3 | (M3,5) | M4 | M5 | M6 | M8 | M10 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2 | 1,8 | 2,2 | 0,075 | |||||||||
| 2.5 | 2.3 | 2,7 | 0,081 | 0,152 | ||||||||
| 3 | 2,8 | 3,2 | 0,087 | 0,161 | 0,281 | |||||||
| 4 | 3,76 | 4,24 | 0,099 | 0,18 | 0,311 | 0,463 | ||||||
| 5 | 4,76 | 5,24 | 0,11 | 0,198 | 0,341 | 0,507 | 0,825 | 1,16 | ||||
| 6 | 5,76 | 6,24 | 0,122 | 0,217 | 0,371 | 0,551 | 0,885 | 1,24 | 2,12 | |||
| 8 | 7.71 | 8,29 | 0,145 | 0,254 | 0,431 | 0,639 | 1 | 1,39 | 2,37 | 4,02 | ||
| 10 | 9,71 | 10,29 | 0,168 | 0,292 | 0,491 | 0,727 | 1,12 | 1,55 | 2,61 | 4,37 | 9,38 | |
| 12 | 11,65 | 12,35 | 0,192 | 0,329 | 0,551 | 0,816 | 1,24 | 1.7 | 2,86 | 4,72 | 10 | 18,2 |
| (14) | 13,65 | 14,35 | 0,215 | 0,366 | 0,611 | 0,904 | 1,36 | 1,86 | 3,11 | 5,1 | 10,6 | 19,2 |
| 16 | 15,65 | 16,35 | 0,238 | 0,404 | 0,671 | 0,992 | 1,48 | 2,01 | 3,36 | 5,45 | 11,2 | 20,2 |
| 20 | 19,58 | 20,42 | 0,478 | 0,792 | 1,17 | 1,72 | 2,32 | 3,85 | 6,14 | 12,6 | 22,2 | |
| 25 | 24,58 | 25,42 | 0,942 | 1,39 | 2,02 | 2,71 | 4,47 | 7,01 | 14,1 | 24,7 | ||
| 30 | 29,58 | 30,42 | 1,61 | 2,32 | 3,1 | 5,09 | 7,9 | 15,7 | 27,2 | |||
| 35 | 34,5 | 35,5 | 2,62 | 3,48 | 5,71 | 8,78 | 17,3 | 29,7 | ||||
| 40 | 39,5 | 40,5 | 3,87 | 6,32 | 9,66 | 18,9 | 32,2 | |||||
| 45 | 44,5 | 45,5 | 6,94 | 10,5 | 20,5 | 34,7 | ||||||
| 50 | 49,5 | 50,5 | 7,56 | 11,4 | 22,1 | 37,2 | ||||||
| (55) | 54,05 | 55,95 | 12,3 | 23,7 | 39,7 | |||||||
| 60 | 59,05 | 60,95 | 13,2 | 25,3 | 42,2 | |||||||
| (65) | 64,05 | 65,95 | 26,9 | 44,7 | ||||||||
| 70 | 69,05 | 70,95 | 28,5 | 47,2 | ||||||||
| (75) | 74,05 | 75,95 | 30,1 | 49,7 | ||||||||
| 80 | 79,05 | 80,95 | 31,7 | 52,2 |
Materials
- Property class and finish specified per RFQ — slotted pan heads are commonly 4.8 steel, brass or stainless for instrument and electrical work; state the application at quotation
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 1580 Slotted Pan Head 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 would anyone still spec a slotted head for a machine screw?
Three honest reasons. Cost: the slot is the cheapest head form to roll and the flat blade the cheapest tool to own — for a low-torque terminal or an instrument cover, that is decisive. Field service: a flat blade is the one driver guaranteed present anywhere in the world, and it works half-worn, which matters on maintained equipment. Reversibility-by-damage: a cam-out event chews the slot instead of snapping the driver or the operator's wrist — on low-spec joints that is a benign failure. What the slot cannot do is hold torque, and the collected geometry quantifies the price: slot depth t min. 1 mm at M4 against a hexalobular socket nearly twice as deep on the ISO 14579 page. So: slotted where torque is small and service is by hand; six-lobe where it is not. Property class (4.8-class is the usual reading of this series) and finish stay per RFQ — the source tabulates geometry and weight only.
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