Drop-in T-nuts for 20, 30, 40 and 10-series (1 in) extrusion — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/drop-in-t-nuts/  (CC BY 4.0)
Basis: Drop-in nut: width = slot opening so it passes the opening, length = cavity − 1 so it turns 90° (designed), tap-drill thread hole
Catalog version: 2026-10-20

Sizes: see table below
- The nut is as wide as the slot opening, so it drops in through the face, and 1 mm shorter than the cavity width, so it turns 90° to lock behind the lips (designed).
- 20-series: 10 × 6 × 4.2 body with a 6 × 6 × 1.8 boss, M3 / M4 / M5. 30-series: 15.5 × 8 × 6, boss 8 × 8 × 2.5, M5 / M6 / M8. 40-series: 19 × 8 × 6.5, boss 8 × 8 × 3, M6 / M8. 10-series: 13.4 × 6.5 × 4.8, boss 6.5 × 6.5 × 2.3, 1/4-20 / 10-32.
- Thread holes are the standard tap drills (M3 2.5, M4 3.3, M5 4.2, M6 5.0, M8 6.8, 1/4-20 5.1, 10-32 4.0); body edges carry a 1.2 mm chamfer.
- Use a drop-in nut where the profile end is already closed.

series  body_mm  boss_mm  threads
20  10 × 6 × 4.2  6 × 6 × 1.8  M3, M4, M5
30  15.5 × 8 × 6  8 × 8 × 2.5  M5, M6, M8
40  19 × 8 × 6.5  8 × 8 × 3  M6, M8
10 (1 in)  13.4 × 6.5 × 4.8  6.5 × 6.5 × 2.3  1/4-20, 10-32

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: T-slot nut — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/T-slot_nut
- OpenBuilds: Tee nuts and brackets for V-slot — web, STEP — OpenBuilds site [verify license at link] — https://openbuildspartstore.com/
- Long Earth Society: Engine and rig builds on extrusion frames — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 10 parts): https://xemstudio.com/files/hardware/drop-in-t-nuts/index.json
API: https://xemstudio.com/api/geometry?object=drop-in-t-nuts