# Helical wire thread inserts (Helicoil style, DIN 8140): M3–M16 drill size, tapped hole, insert length 1D–3D

> What drill size and tap for an M6 Helicoil insert, and how long are 1D, 1.5D and 2D inserts?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: HONSEL's metric coil catalog (DIN 8140-1 coils, DIN 8140-2 receiving thread), cross-checked on M5 against McMaster-Carr's M5 x 0.8 helical insert page; numbers only
- Page: https://xemstudio.com/objects/helical-thread-inserts-din-8140/ · JSON: https://xemstudio.com/api/geometry?object=helical-thread-inserts-din-8140 · Plain text: https://xemstudio.com/objects/helical-thread-inserts-din-8140/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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**Exact dimensions.** True size, with no tolerance added.

## Notes

- Columns (mm) as the HONSEL catalog prints them: P pitch; d1 coil major diameter before installation (min / max); d2 guide drill diameter, for cutting taps and for thread formers (the catalog says it must be adjusted to the application and material); D1 EG the minor diameter of the receiving thread (min / max), which fixes the drill; D EG min the major diameter of the receiving thread; l5 the distance from the coil to the surface (0.25 P to 0.75 P); l1 the nominal coil length at 1D, 1.5D, 2D, 2.5D and 3D. The M16 and M16 x 1.5 rows list lengths from 1D to 2.5D only. Installed length is l1 minus one pitch (l2 = l1 − P). The 'tap' is the special insert tap for the receiving thread (D EG); the catalog lists no tap part numbers or dimensions, only that cutting taps and thread formers exist.
- Cross-check: McMaster-Carr's M5 x 0.8 page lists installed lengths 5, 7.5, 10, 12.5 and 15 mm (1x to 3x), matching HONSEL's l1 for M5, and drill sizes 5.3 mm for most inserts and 5.2 mm for the 3x length and for the kits; HONSEL's M5 d2 is 5.20 (cutting) and 5.70 (forming), D1 EG 5.17 to 5.33. Drill sizes differ by source and tapping method: use the maker's chart for your insert line.
- Hole depths (l3, l4, l6, W turns) are defined in the catalog but its text extraction did not map the numbers cleanly, so they are not tabulated. DIN 8140 is the wire thread insert standard (parts 1 and 2 cited by the catalog). Imperial Helicoil sizes were not read from a table and are not listed.
- No file: a coil insert is a sprung wire coil whose geometry is not published as numbers; a hole gauge at an assumed drill size would be invented. For plastic parts: heat-set-inserts, heat-set-inserts-inch; for sheet metal: rivet-nuts-flat-head and the PEM pages. McMaster-Carr sells helical inserts with per-part STEP; the page and a DIN 8140 filter are linked, not copied.

## Sizes

| size | P (mm) | d1 coil major min / max | d2 drill (cutting) | d2 drill (forming) | D1 EG minor min / max | D EG major min | l5 | l1 1D | l1 1.5D | l1 2D | l1 2.5D | l1 3D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 3.80 / 4.00 | 3.20 | 3.40 | 3.11 / 3.22 | 3.65 | 0.1–0.4 | 3.0 | 4.5 | 6.0 | 7.5 | 9.0 |
| M4 | 0.7 | 5.15 / 5.35 | 4.20 | 4.60 | 4.15 / 4.29 | 4.91 | 0.2–0.5 | 4 | 6 | 8 | 10 | 12 |
| M5 | 0.8 | 6.35 / 6.60 | 5.20 | 5.70 | 5.17 / 5.33 | 6.04 | 0.2–0.6 | 5 | 7.5 | 10 | 12.5 | 15 |
| M6 | 1 | 7.60 / 7.85 | 6.30 | 6.80 | 6.22 / 6.41 | 7.30 | 0.3–0.8 | 6 | 9 | 12 | 15 | 18 |
| M8 | 1.25 | 9.85 / 10.10 | 8.40 | 9.10 | 8.27 / 8.48 | 9.62 | 0.3–0.9 | 8 | 12 | 16 | 20 | 24 |
| M10 | 1.5 | 12.10 / 12.50 | 10.50 | 11.30 | 10.32 / 10.56 | 11.95 | 0.4–1.1 | 10 | 15 | 20 | 25 | 30 |
| M12 | 1.75 | 14.40 / 14.80 | 12.50 | 13.50 | 12.38 / 12.64 | 14.27 | 0.4–1.3 | 12 | 18 | 24 | 30 | 36 |
| M12 x 1.5 | 1.5 | 14.40 / 14.80 | 12.50 | 13.30 | 12.32 / 12.56 | 13.95 | 0.4–1.1 | 12 | 18 | 24 | 30 | 36 |
| M14 | 2 | 16.80 / 17.20 | 14.50 | 15.70 | 14.43 / 14.73 | 16.60 | 0.5–1.5 | 14 | 21 | 28 | 35 | 42 |
| M14 x 1.5 | 1.5 | 16.80 / 17.20 | 14.50 | 15.30 | 14.38 / 14.56 | 15.95 | 0.4–1.1 | 14 | 21 | 28 | 35 | 42 |
| M16 | 2 | 19.00 / 19.40 | 16.50 | 17.70 | 16.43 / 16.73 | 18.60 | 0.5–1.5 | 16 | 24 | 32 | 40 | — |
| M16 x 1.5 | 1.5 | 19.00 / 19.40 | 16.50 | 17.30 | 16.32 / 16.56 | 17.95 | 0.4–1.1 | 16 | 24 | 32 | 40 | — |

## Where the files are

- HONSEL: [Coils (wire thread inserts, DIN 8140-1) and receiving thread (DIN 8140-2), metric: P, d1, drill d2 (cutting / forming), receiving thread D1 EG and D EG, l5, l1 at 1D to 3D](https://oxomi.com/dasd/xxl/pd/documents/f8570a84a9432ff62b5355ef240bdd91/SMD6PCMG4QLB1QIO94PGK5U70S/7UDP8EIH5ETNUO4USKM2U497PC/HONSEL_Coils_ENGLISH.pdf) — web — Maker catalog; numbers only
- McMaster-Carr: [Helical thread inserts (M5 x 0.8 page: lengths 1x to 3x, drill 5.2 / 5.3) (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/helicoils/thread-size~m5/) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)
- McMaster-Carr: [Threaded inserts, DIN 8140 filter (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/threaded-inserts/specifications-met~din-8140) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Questions

**What drill for an M6 Helicoil insert?**

HONSEL's guide drill d2 is 6.30 mm for cutting taps and 6.80 mm for thread formers; the receiving-thread minor diameter is 6.22 to 6.41 mm.

**How long is a 1.5D M8 insert?**

12 mm nominal (l1), installed about 10.75 mm (l1 minus one 1.25 mm pitch).

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