# Heat-set insert holes: hole cutters and test bosses for every insert size

> How do I model the hole for a heat-set insert?

- Category: Hardware › Fasteners
- Kind: Hardware
- Basis: the CNC Kitchen hole Ø and L + 1 depth per insert; boss OD = hole + 2 × min wall; drawn by Xem Studio
- Page: https://xemstudio.com/objects/heat-set-insert-holes/ · JSON: https://xemstudio.com/api/geometry?object=heat-set-insert-holes · Plain text: https://xemstudio.com/objects/heat-set-insert-holes/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

- Hole cutter: a cylinder at the hole Ø, insert length + 1 mm long, top face at z = 0: drop it into your model at the screw point and subtract it.
- Test boss: print one first to check the hole with your printer and plastic before printing the real part; a screw clearance hole runs through so you can test-tighten from below.

## Sizes

| thread | insert_length_mm | hole_mm | hole_depth_mm | boss_od_mm |
|---|---|---|---|---|
| M2 | 3.0 | 3.2 | 4.0 | 5.8 |
| M2.5 | 4.0 | 4.0 | 5.0 | 7.2 |
| M3 | 5.7 | 4.0 | 6.7 | 7.2 |
| M3 | 3.0 | 4.0 | 4.0 | 7.2 |
| M3 | 4.0 | 4.4 | 5.0 | 7.6 |
| M4 | 8.1 | 5.7 | 9.1 | 9.9 |
| M4 | 4.0 | 5.7 | 5.0 | 9.9 |
| M5 | 9.5 | 6.5 | 10.5 | 11.7 |
| M5 | 5.8 | 6.5 | 6.8 | 11.7 |
| M6 | 12.7 | 8.1 | 13.7 | 14.7 |
| M8 | 12.7 | 9.7 | 13.7 | 18.7 |
| M10 | 12.7 | 12.0 | 13.7 | 24.0 |
| #2-56 | 3.2 | 3.2 | 4.2 | 5.8 |
| #4-40 | 5.7 | 4.0 | 6.7 | 7.2 |
| #4-40 | 3.6 | 4.0 | 4.6 | 7.2 |
| #6-32 | 7.1 | 4.8 | 8.1 | 8.4 |
| #6-32 | 3.8 | 4.8 | 4.8 | 8.4 |
| #8-32 | 8.2 | 5.7 | 9.2 | 9.9 |
| #8-32 | 4.7 | 5.7 | 5.7 | 9.9 |
| #10-24 | 9.5 | 6.5 | 10.5 | 11.7 |
| #10-32 | 9.5 | 6.5 | 10.5 | 11.7 |
| 1/4-20 | 12.7 | 8.1 | 13.7 | 14.7 |
| 1/4-20 | 6.4 | 8.1 | 7.4 | 14.7 |
| 5/16-18 | 12.7 | 9.7 | 13.7 | 18.7 |
| 3/8-16 | 12.7 | 12.0 | 13.7 | 24.0 |
| G1/8 | 12.7 | 12.0 | 13.7 | 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 (52 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/heat-set-insert-holes/index.json

- hole-cutter-m2x3: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m2x3.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m2x3.stl) — M2 × 3 hole cutter: Ø3.2 × 4 (subtract from your part, top at z = 0)
- test-boss-m2x3: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m2x3.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m2x3.stl) — M2 × 3 test boss: Ø5.8 × 7, insert hole Ø3.2 × 4 on top, screw clearance through
- hole-cutter-m2_5x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m2_5x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m2_5x4.stl) — M2.5 × 4 hole cutter: Ø4 × 5 (subtract from your part, top at z = 0)
- test-boss-m2_5x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m2_5x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m2_5x4.stl) — M2.5 × 4 test boss: Ø7.2 × 8, insert hole Ø4 × 5 on top, screw clearance through
- hole-cutter-m3x5.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x5.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x5.7.stl) — M3 × 5.7 hole cutter: Ø4 × 6.7 (subtract from your part, top at z = 0)
- test-boss-m3x5.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x5.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x5.7.stl) — M3 × 5.7 test boss: Ø7.2 × 9.7, insert hole Ø4 × 6.7 on top, screw clearance through
- hole-cutter-m3x3: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x3.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x3.stl) — M3 × 3 hole cutter: Ø4 × 4 (subtract from your part, top at z = 0)
- test-boss-m3x3: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x3.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x3.stl) — M3 × 3 test boss: Ø7.2 × 7, insert hole Ø4 × 4 on top, screw clearance through
- hole-cutter-m3x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m3x4.stl) — M3 × 4 hole cutter: Ø4.4 × 5 (subtract from your part, top at z = 0)
- test-boss-m3x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m3x4.stl) — M3 × 4 test boss: Ø7.6 × 8, insert hole Ø4.4 × 5 on top, screw clearance through
- hole-cutter-m4x8.1: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m4x8.1.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m4x8.1.stl) — M4 × 8.1 hole cutter: Ø5.7 × 9.1 (subtract from your part, top at z = 0)
- test-boss-m4x8.1: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m4x8.1.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m4x8.1.stl) — M4 × 8.1 test boss: Ø9.9 × 12.1, insert hole Ø5.7 × 9.1 on top, screw clearance through
- hole-cutter-m4x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m4x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m4x4.stl) — M4 × 4 hole cutter: Ø5.7 × 5 (subtract from your part, top at z = 0)
- test-boss-m4x4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m4x4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m4x4.stl) — M4 × 4 test boss: Ø9.9 × 8, insert hole Ø5.7 × 5 on top, screw clearance through
- hole-cutter-m5x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m5x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m5x9.5.stl) — M5 × 9.5 hole cutter: Ø6.5 × 10.5 (subtract from your part, top at z = 0)
- test-boss-m5x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m5x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m5x9.5.stl) — M5 × 9.5 test boss: Ø11.7 × 13.5, insert hole Ø6.5 × 10.5 on top, screw clearance through
- hole-cutter-m5x5.8: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m5x5.8.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m5x5.8.stl) — M5 × 5.8 hole cutter: Ø6.5 × 6.8 (subtract from your part, top at z = 0)
- test-boss-m5x5.8: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m5x5.8.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m5x5.8.stl) — M5 × 5.8 test boss: Ø11.7 × 9.8, insert hole Ø6.5 × 6.8 on top, screw clearance through
- hole-cutter-m6x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m6x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m6x12.7.stl) — M6 × 12.7 hole cutter: Ø8.1 × 13.7 (subtract from your part, top at z = 0)
- test-boss-m6x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m6x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m6x12.7.stl) — M6 × 12.7 test boss: Ø14.7 × 16.7, insert hole Ø8.1 × 13.7 on top, screw clearance through
- hole-cutter-m8x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m8x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m8x12.7.stl) — M8 × 12.7 hole cutter: Ø9.7 × 13.7 (subtract from your part, top at z = 0)
- test-boss-m8x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m8x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m8x12.7.stl) — M8 × 12.7 test boss: Ø18.7 × 16.7, insert hole Ø9.7 × 13.7 on top, screw clearance through
- hole-cutter-m10x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m10x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-m10x12.7.stl) — M10 × 12.7 hole cutter: Ø12 × 13.7 (subtract from your part, top at z = 0)
- test-boss-m10x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m10x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-m10x12.7.stl) — M10 × 12.7 test boss: Ø24.0 × 16.7, insert hole Ø12 × 13.7 on top, screw clearance through
- hole-cutter-2-56x3.2: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-2-56x3.2.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-2-56x3.2.stl) — #2-56 × 3.2 hole cutter: Ø3.2 × 4.2 (subtract from your part, top at z = 0)
- test-boss-2-56x3.2: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-2-56x3.2.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-2-56x3.2.stl) — #2-56 × 3.2 test boss: Ø5.8 × 7.2, insert hole Ø3.2 × 4.2 on top, screw clearance through
- hole-cutter-4-40x5.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-4-40x5.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-4-40x5.7.stl) — #4-40 × 5.7 hole cutter: Ø4 × 6.7 (subtract from your part, top at z = 0)
- test-boss-4-40x5.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-4-40x5.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-4-40x5.7.stl) — #4-40 × 5.7 test boss: Ø7.2 × 9.7, insert hole Ø4 × 6.7 on top, screw clearance through
- hole-cutter-4-40x3.6: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-4-40x3.6.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-4-40x3.6.stl) — #4-40 × 3.6 hole cutter: Ø4 × 4.6 (subtract from your part, top at z = 0)
- test-boss-4-40x3.6: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-4-40x3.6.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-4-40x3.6.stl) — #4-40 × 3.6 test boss: Ø7.2 × 7.6, insert hole Ø4 × 4.6 on top, screw clearance through
- hole-cutter-6-32x7.1: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-6-32x7.1.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-6-32x7.1.stl) — #6-32 × 7.1 hole cutter: Ø4.8 × 8.1 (subtract from your part, top at z = 0)
- test-boss-6-32x7.1: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-6-32x7.1.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-6-32x7.1.stl) — #6-32 × 7.1 test boss: Ø8.4 × 11.1, insert hole Ø4.8 × 8.1 on top, screw clearance through
- hole-cutter-6-32x3.8: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-6-32x3.8.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-6-32x3.8.stl) — #6-32 × 3.8 hole cutter: Ø4.8 × 4.8 (subtract from your part, top at z = 0)
- test-boss-6-32x3.8: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-6-32x3.8.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-6-32x3.8.stl) — #6-32 × 3.8 test boss: Ø8.4 × 7.8, insert hole Ø4.8 × 4.8 on top, screw clearance through
- hole-cutter-8-32x8.2: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-8-32x8.2.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-8-32x8.2.stl) — #8-32 × 8.2 hole cutter: Ø5.7 × 9.2 (subtract from your part, top at z = 0)
- test-boss-8-32x8.2: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-8-32x8.2.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-8-32x8.2.stl) — #8-32 × 8.2 test boss: Ø9.9 × 12.2, insert hole Ø5.7 × 9.2 on top, screw clearance through
- hole-cutter-8-32x4.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-8-32x4.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-8-32x4.7.stl) — #8-32 × 4.7 hole cutter: Ø5.7 × 5.7 (subtract from your part, top at z = 0)
- test-boss-8-32x4.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-8-32x4.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-8-32x4.7.stl) — #8-32 × 4.7 test boss: Ø9.9 × 8.7, insert hole Ø5.7 × 5.7 on top, screw clearance through
- hole-cutter-10-24x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-10-24x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-10-24x9.5.stl) — #10-24 × 9.5 hole cutter: Ø6.5 × 10.5 (subtract from your part, top at z = 0)
- test-boss-10-24x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-10-24x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-10-24x9.5.stl) — #10-24 × 9.5 test boss: Ø11.7 × 13.5, insert hole Ø6.5 × 10.5 on top, screw clearance through
- hole-cutter-10-32x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-10-32x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-10-32x9.5.stl) — #10-32 × 9.5 hole cutter: Ø6.5 × 10.5 (subtract from your part, top at z = 0)
- test-boss-10-32x9.5: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-10-32x9.5.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-10-32x9.5.stl) — #10-32 × 9.5 test boss: Ø11.7 × 13.5, insert hole Ø6.5 × 10.5 on top, screw clearance through
- hole-cutter-1-4-20x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-1-4-20x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-1-4-20x12.7.stl) — 1/4-20 × 12.7 hole cutter: Ø8.1 × 13.7 (subtract from your part, top at z = 0)
- test-boss-1-4-20x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-1-4-20x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-1-4-20x12.7.stl) — 1/4-20 × 12.7 test boss: Ø14.7 × 16.7, insert hole Ø8.1 × 13.7 on top, screw clearance through
- hole-cutter-1-4-20x6.4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-1-4-20x6.4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-1-4-20x6.4.stl) — 1/4-20 × 6.4 hole cutter: Ø8.1 × 7.4 (subtract from your part, top at z = 0)
- test-boss-1-4-20x6.4: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-1-4-20x6.4.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-1-4-20x6.4.stl) — 1/4-20 × 6.4 test boss: Ø14.7 × 10.4, insert hole Ø8.1 × 7.4 on top, screw clearance through
- hole-cutter-5-16-18x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-5-16-18x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-5-16-18x12.7.stl) — 5/16-18 × 12.7 hole cutter: Ø9.7 × 13.7 (subtract from your part, top at z = 0)
- test-boss-5-16-18x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-5-16-18x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-5-16-18x12.7.stl) — 5/16-18 × 12.7 test boss: Ø18.7 × 16.7, insert hole Ø9.7 × 13.7 on top, screw clearance through
- hole-cutter-3-8-16x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-3-8-16x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-3-8-16x12.7.stl) — 3/8-16 × 12.7 hole cutter: Ø12 × 13.7 (subtract from your part, top at z = 0)
- test-boss-3-8-16x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-3-8-16x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-3-8-16x12.7.stl) — 3/8-16 × 12.7 test boss: Ø24.0 × 16.7, insert hole Ø12 × 13.7 on top, screw clearance through
- hole-cutter-g1-8x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-g1-8x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/hole-cutter-g1-8x12.7.stl) — G1/8 × 12.7 hole cutter: Ø12 × 13.7 (subtract from your part, top at z = 0)
- test-boss-g1-8x12.7: [STEP](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-g1-8x12.7.step) · [STL](https://xemstudio.com/files/hardware/heat-set-insert-holes/test-boss-g1-8x12.7.stl) — G1/8 × 12.7 test boss: Ø24.0 × 16.7, insert hole Ø12 × 13.7 on top, screw clearance through

## Questions

**Why one more millimetre of depth?**

Plastic melted by the insert flows ahead of it; the extra depth gives it somewhere to go so the insert seats flush.

## Fits with

- [Heat-set threaded inserts, metric: M2 to M10, standard, short and Voron (CNC Kitchen sizes)](https://xemstudio.com/objects/heat-set-inserts/)
- [Heat-set threaded inserts, inch: #2-56 to 3/8-16 and G1/8 (CNC Kitchen sizes)](https://xemstudio.com/objects/heat-set-inserts-inch/)
- [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/)