# Self-drilling screws DIN 7504: hexagon washer head (type K) and pan / countersunk heads (N, P), ST2.2–ST6.3: head diameter, height, drill-point diameter, drilling depth

> What are the hex washer head dimensions (across flats, washer diameter, height) of an ST4.8 or ST5.5 self-drilling screw, and how thick a sheet does it drill?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: fasten.it's DIN 7504 tables (09/1995, now cancelled): types K, N and P with the page's own column letters; numbers only
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**Exact dimensions.** True size, with no tolerance added.

## Notes

- Millimetres. DIN 7504 is the (cancelled) standard for self-drilling tapping screws; fasten.it still prints it. Sizes ST2.2 to ST6.3. The page does not define its column letters, so none is interpreted beyond the names the page gives. For type K (hexagon washer head) the columns are P (pitch), h min, k (max / min), dc (min – max), s (min – max) and dp max; read from the shape of the head, dc is the washer diameter and s the hexagon width across flats, but the page does not say so. Types N and P print k and dk (min – max) and dp max; type R is printed identically to P; type L (hex head with slot) was read too and is not tabulated.
- 'Drilling depth, from – to' is printed as a row of seven value pairs without clear column alignment; the pairs were matched to ST2.9, 3.5, 3.9, 4.2, 4.8, 5.5, 6.3 in the order printed, so treat that column as read in order, not as a verified table. The page's heading for the block is 'Drilling depth (sheet, plate, thickness)' with a drill-point figure; the numbers are not interpreted further. The standard's minimum grip length (lg) table is printed without headers and is not used.
- Compare with the drilling ranges makers print for inch Tek points on tek-self-drilling-screw-drill-points: the two sets are not the same measure and are not converted.
- No file: head chamfers, washer face, drill-flute and thread geometry are not published as numbers on the page; a drawing from k, dc and s alone would be an invented shape.

## Sizes

| head type | thread | P | k (max / min) | dc or dk (min – max) | s (min – max; reads as width across flats) | h min | dp max | drilling depth from – to (mm, read in order) |
|---|---|---|---|---|---|---|---|---|
| Type K (hexagon washer head) | ST2.9 | 1.1 | k 2.8 / 2.5 | dc 5.8 – 6.3 | s 3.82 – 4 | h min 0.4 | dp max 2.3 | 0.7 – 1.9 |
| Type K (hexagon washer head) | ST3.5 | 1.3 | k 3.4 / 3 | dc 7.6 – 8.3 | s 5.32 – 5.5 | h min 0.6 | dp max 2.8 | 0.7 – 2.25 |
| Type K (hexagon washer head) | ST3.9 | 1.3 | k 3.4 / 3 | dc 7.6 – 8.3 | s 5.32 – 5.5 | h min 0.6 | dp max 3.1 | 0.7 – 2.4 |
| Type K (hexagon washer head) | ST4.2 | 1.4 | k 4.1 / 3.6 | dc 8.1 – 8.8 | s 6.78 – 7 | h min 0.8 | dp max 3.6 | 1.75 – 3 |
| Type K (hexagon washer head) | ST4.8 | 1.6 | k 4.3 / 3.8 | dc 9.8 – 10.5 | s 7.78 – 8 | h min 0.9 | dp max 4.1 | 1.75 – 4.4 |
| Type K (hexagon washer head) | ST5.5 | 1.8 | k 5.4 / 4.8 | dc 10 – 11 | s 7.78 – 8 | h min 1 | dp max 4.8 | 1.75 – 5.25 |
| Type K (hexagon washer head) | ST6.3 | 1.8 | k 5.9 / 5.3 | dc 12.2 – 13.5 | s 9.78 – 10 | h min 1 | dp max 5.8 | 2 – 6 |
| Type N | ST2.2 | 0.8 | k 1.6 / 1.4 | dk 3.7 – 4 | — | — | dp max 2.3 | — |
| Type N | ST2.9 | 1.1 | k 2.4 / 2.15 | dk 5.3 – 5.6 | — | — | dp max 2.8 | 0.7 – 1.9 |
| Type N | ST3.5 | 1.3 | k 2.6 / 2.35 | dk 6.64 – 7 | — | — | dp max 3.1 | 0.7 – 2.25 |
| Type N | ST4.2 | 1.4 | k 3.1 / 2.8 | dk 7.64 – 8 | — | — | dp max 3.6 | 1.75 – 3 |
| Type N | ST4.8 | 1.6 | k 3.7 / 3.4 | dk 9.14 – 9.5 | — | — | dp max 4.1 | 1.75 – 4.4 |
| Type N | ST5.5 | 1.8 | k 4 / 3.7 | dk 10.57 – 11 | — | — | dp max 4.8 | 1.75 – 5.25 |
| Type N | ST6.3 | 1.8 | k 4.6 / 4.3 | dk 11.57 – 12 | — | — | dp max 5.8 | 2 – 6 |
| Type P (also type R, identical table) | ST2.2 | 0.8 | k max 1.1 | dk 3.5 – 3.8 | — | — | dp max 2.3 | — |
| Type P (also type R, identical table) | ST2.9 | 1.1 | k max 1.7 | dk 5.2 – 5.5 | — | — | dp max 2.8 | 0.7 – 1.9 |
| Type P (also type R, identical table) | ST3.5 | 1.3 | k max 2.35 | dk 6.9 – 7.3 | — | — | dp max 3.1 | 0.7 – 2.25 |
| Type P (also type R, identical table) | ST4.2 | 1.4 | k max 2.6 | dk 8 – 8.4 | — | — | dp max 3.6 | 1.75 – 3 |
| Type P (also type R, identical table) | ST4.8 | 1.6 | k max 2.8 | dk 8.9 – 9.3 | — | — | dp max 4.1 | 1.75 – 4.4 |
| Type P (also type R, identical table) | ST5.5 | 1.8 | k max 3 | dk 9.9 – 10.3 | — | — | dp max 4.8 | 1.75 – 5.25 |
| Type P (also type R, identical table) | ST6.3 | 1.8 | k max 3.15 | dk 10.9 – 11.3 | — | — | dp max 5.8 | 2 – 6 |

## Where the files are

- fasten.it: [DIN 7504 self-drilling tapping screws, 09/1995 (cancelled): types K (hexagon washer head), L, N, P, R; ST2.2 to ST6.3: P, h, k, dc, s, dk, dp and drilling depth](https://fasten.it/en/norms/norm/din_7504) — web — Reference page; numbers only. The page does not define the column letters

## Questions

**What is the width across flats of an ST4.8 hex washer head self-drilling screw?**

DIN 7504 type K: the s column is 7.78 – 8 mm for ST4.8 (and ST5.5), the washer column dc 9.8 – 10.5 mm, height k 4.3 max / 3.8 min.

**How thick a sheet does an ST5.5 self-drilling screw drill?**

The page's drilling-depth row, read in order, gives 1.75 – 5.25 mm for ST5.5 (matched by position, not by column header).

**Is DIN 7504 still current?**

fasten.it marks the 09/1995 edition as cancelled; the page remains a useful size table.

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