# Heat-set threaded inserts, inch: #2-56 to 3/8-16 and G1/8 (CNC Kitchen sizes)

> What hole size does a 1/4-20 heat-set insert need?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: CNC Kitchen dimension poster (L, insert Ø D1, hole Ø D2, min wall W, blind hole ≥ L + 1); geometry drawn by Xem Studio from those numbers
- Page: https://xemstudio.com/objects/heat-set-inserts-inch/ · JSON: https://xemstudio.com/api/geometry?object=heat-set-inserts-inch · Plain text: https://xemstudio.com/objects/heat-set-inserts-inch/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Drawn as: lead-in pilot at the tip Ø over the bottom 15 % of the length, two knurl bands at the insert Ø with a relief groove between, thread as a plain bore at the minor diameter (threads not modelled). Knurl texture is not drawn: the insert Ø is the knurl's outside.
- Print the hole at the listed hole Ø, at least the insert length + 1 mm deep for a blind hole (room for displaced plastic), and keep at least W of wall around it. Press the insert in with a soldering iron and insert tip at the plastic's printing temperature until its top is flush.

## Sizes

| thread | variant | length_mm | insert_od_mm | hole_mm | min_hole_depth_mm | min_wall_mm | min_boss_od_mm |
|---|---|---|---|---|---|---|---|
| #2-56 | standard | 3.2 | 3.6 | 3.2 | 4.2 | 1.3 | 5.8 |
| #4-40 | standard | 5.7 | 4.6 | 4.0 | 6.7 | 1.6 | 7.2 |
| #4-40 | short | 3.6 | 4.6 | 4.0 | 4.6 | 1.6 | 7.2 |
| #6-32 | standard | 7.1 | 5.4 | 4.8 | 8.1 | 1.8 | 8.4 |
| #6-32 | short | 3.8 | 5.4 | 4.8 | 4.8 | 1.8 | 8.4 |
| #8-32 | standard | 8.2 | 6.3 | 5.7 | 9.2 | 2.1 | 9.9 |
| #8-32 | short | 4.7 | 6.3 | 5.7 | 5.7 | 2.1 | 9.9 |
| #10-24 | standard | 9.5 | 7.1 | 6.5 | 10.5 | 2.6 | 11.7 |
| #10-32 | standard | 9.5 | 7.1 | 6.5 | 10.5 | 2.6 | 11.7 |
| 1/4-20 | standard | 12.7 | 8.7 | 8.1 | 13.7 | 3.3 | 14.7 |
| 1/4-20 | short | 6.4 | 8.7 | 8.1 | 7.4 | 3.3 | 14.7 |
| 5/16-18 | standard | 12.7 | 10.2 | 9.7 | 13.7 | 4.5 | 18.7 |
| 3/8-16 | standard | 12.7 | 12.5 | 12.0 | 13.7 | 6.0 | 24.0 |
| G1/8 | standard | 12.7 | 12.5 | 12.0 | 13.7 | 6.0 | 24.0 |

## Where the files are

- CNC Kitchen: [Threaded insert dimensions and design guidelines poster: L, D1 (insert Ø), D2 (hole Ø), W (min wall); blind hole min. L + 1 mm](https://cdn.shopify.com/s/files/1/0654/4821/4767/files/Poster_Dimensions-Guidlines.pdf?v=1751444185) — PDF — maker's sheet; dimensions cited, nothing copied

## Free STEP/STL (14 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/heat-set-inserts-inch/index.json

- insert-2-56x3.2-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-2-56x3.2-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-2-56x3.2-standard.stl) — #2-56 × 3.2 standard insert: Ø3.6 knurl, 3.2 long; print hole Ø3.2 × ≥4.2, wall ≥ 1.3
- insert-4-40x5.7-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-4-40x5.7-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-4-40x5.7-standard.stl) — #4-40 × 5.7 standard insert: Ø4.6 knurl, 5.7 long; print hole Ø4 × ≥6.7, wall ≥ 1.6
- insert-4-40x3.6-short: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-4-40x3.6-short.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-4-40x3.6-short.stl) — #4-40 × 3.6 short insert: Ø4.6 knurl, 3.6 long; print hole Ø4 × ≥4.6, wall ≥ 1.6
- insert-6-32x7.1-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-6-32x7.1-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-6-32x7.1-standard.stl) — #6-32 × 7.1 standard insert: Ø5.4 knurl, 7.1 long; print hole Ø4.8 × ≥8.1, wall ≥ 1.8
- insert-6-32x3.8-short: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-6-32x3.8-short.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-6-32x3.8-short.stl) — #6-32 × 3.8 short insert: Ø5.4 knurl, 3.8 long; print hole Ø4.8 × ≥4.8, wall ≥ 1.8
- insert-8-32x8.2-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-8-32x8.2-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-8-32x8.2-standard.stl) — #8-32 × 8.2 standard insert: Ø6.3 knurl, 8.2 long; print hole Ø5.7 × ≥9.2, wall ≥ 2.1
- insert-8-32x4.7-short: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-8-32x4.7-short.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-8-32x4.7-short.stl) — #8-32 × 4.7 short insert: Ø6.3 knurl, 4.7 long; print hole Ø5.7 × ≥5.7, wall ≥ 2.1
- insert-10-24x9.5-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-10-24x9.5-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-10-24x9.5-standard.stl) — #10-24 × 9.5 standard insert: Ø7.1 knurl, 9.5 long; print hole Ø6.5 × ≥10.5, wall ≥ 2.6
- insert-10-32x9.5-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-10-32x9.5-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-10-32x9.5-standard.stl) — #10-32 × 9.5 standard insert: Ø7.1 knurl, 9.5 long; print hole Ø6.5 × ≥10.5, wall ≥ 2.6
- insert-1-4-20x12.7-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-1-4-20x12.7-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-1-4-20x12.7-standard.stl) — 1/4-20 × 12.7 standard insert: Ø8.7 knurl, 12.7 long; print hole Ø8.1 × ≥13.7, wall ≥ 3.3
- insert-1-4-20x6.4-short: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-1-4-20x6.4-short.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-1-4-20x6.4-short.stl) — 1/4-20 × 6.4 short insert: Ø8.7 knurl, 6.4 long; print hole Ø8.1 × ≥7.4, wall ≥ 3.3
- insert-5-16-18x12.7-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-5-16-18x12.7-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-5-16-18x12.7-standard.stl) — 5/16-18 × 12.7 standard insert: Ø10.2 knurl, 12.7 long; print hole Ø9.7 × ≥13.7, wall ≥ 4.5
- insert-3-8-16x12.7-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-3-8-16x12.7-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-3-8-16x12.7-standard.stl) — 3/8-16 × 12.7 standard insert: Ø12.5 knurl, 12.7 long; print hole Ø12 × ≥13.7, wall ≥ 6
- insert-g1-8x12.7-standard: [STEP](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-g1-8x12.7-standard.step) · [STL](https://xemstudio.com/files/hardware/heat-set-inserts-inch/insert-g1-8x12.7-standard.stl) — G1/8 × 12.7 standard insert: Ø12.5 knurl, 12.7 long; print hole Ø12 × ≥13.7, wall ≥ 6

## Questions

**What hole for a 1/4-20 × 12.7 insert?**

Ø8.1, at least 13.7 deep, 3.3 wall (boss Ø14.7 or more).

**Short or standard?**

Standard holds more; short fits thin walls. Both take the same hole Ø.

## Fits with

- [Heat-set threaded inserts, ruthex RX series: M2 to M8 and #2-56 to 3/8-16](https://xemstudio.com/objects/heat-set-inserts-ruthex/)
- [Heat-set insert holes: hole cutters and test bosses for every insert size](https://xemstudio.com/objects/heat-set-insert-holes/)
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)
- [Imperial machine screws: #4-40, #6-32, #8-32, 1/4-20](https://xemstudio.com/objects/imperial-machine-screws/)