Heat-set insert holes: hole cutters and test bosses for every insert size — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/heat-set-insert-holes/  (CC BY 4.0)
Basis: the CNC Kitchen hole Ø and L + 1 depth per insert; boss OD = hole + 2 × min wall; drawn by Xem Studio
Catalog version: 2026-10-20

Sizes: see table below
- 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.

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

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- 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 — PDF — maker's sheet; dimensions cited, nothing copied — https://cdn.shopify.com/s/files/1/0654/4821/4767/files/Poster_Dimensions-Guidlines.pdf?v=1751444185

Free files (CC BY 4.0, Xem Studio; STEP + STL, 52 parts): https://xemstudio.com/files/hardware/heat-set-insert-holes/index.json
API: https://xemstudio.com/api/geometry?object=heat-set-insert-holes