ISO 4026 Hexagon Socket Set Screw — Flat Point
ISO flat point counterpart to DIN 913. The plain disc end bears on the shaft without cutting into it, so it suits joints that are adjusted repeatedly or shafts whose surface has to stay undamaged. Body dimensions are shared with the cup point page — all four point styles use the same thread and socket sizes.
Where it is used
ISO 4026 is the flat point hexagon socket set screw, the ISO counterpart to DIN 913. The end is a plain disc, so it presses on the shaft without cutting into it — the correct choice where the surface has to stay undamaged or where the joint is adjusted repeatedly.
How to choose it
Grades are marked 14H, 22H, 33H and 45H, the number being minimum surface hardness on the Rockwell C scale; 45H is the common stock grade. A flat point holds by friction alone, which makes it the weakest of the four point styles under vibration — it is a positioning screw, not a locking screw. Where the shaft is soft, pair it with a copper or fibre pad so the point has something to bite into.
Dimensions8 sizes · millimetres
| Thread d | Pitch P (mm) | Socket size s (mm) |
|---|---|---|
| M3 | 0.5 | 1.5 |
| M4 | 0.7 | 2 |
| M5 | 0.8 | 2.5 |
| M6 | 1 | 3 |
| M8 | 1.25 | 4 |
| M10 | 1.5 | 5 |
| M12 | 1.75 | 6 |
| M16 | 2 | 8 |
Nominal dimensions in millimetres as published in ISO 4026. Tolerances, material requirements and marking are defined separately by the issuing body.
Available sizeslinked to individual specification pages
Thread referencesused by the sizes above
Fitting and interchange notes
Shares its body dimensions with the other three ISO set screws, so only the point differs between ISO 4026, 4027, 4028 and 4029 — the same tapped hole takes any of them. Interchangeable with DIN 913. Because the point relies on friction, a flat point screw that has loosened once will usually loosen again: if the joint has to stay put, change the point style rather than simply retightening.