How it connects
A compatible T-nut or hammer nut slides or rolls into the internal channel and clamps against the internal retaining lips when a mating machine screw is tightened.
Male and female halves
Female slot channel mating with male sliding hardware including T-nuts, roll-in nuts, hammer nuts, and fasteners.
Usually connects to
- 20-series M3/M4/M5/M6 T-nut: sliding, drop-in, hammer-head or spring roll-in
- Matching M5/M6 T-bolt, hex bolt or drop-in stud
- Matching framing/corner bracket or gusset plate
- 20-series slot cover
Common sizes
- 20 mm grid profiles include 20 × 20, 20 × 40, 20 × 60 and 20 × 80 mm.
- Typical slot throat 6.0–6.4 mm, inner cavity about 11–12 mm; commonly accepts M3–M6 fasteners.
Where it is used
CNC router and 3D-printer framesRobotics/automationLaboratory framesIndustrial workstations/enclosuresMaker/DIY framing and test rigsLaser cutters
Variations
- 2020: 20 × 20 mm, single-width/single slot per face
- 2040: 20 × 40 mm, 2 × 1 slots
- 2060: 20 × 60 mm, 3 × 1 slots
- 2080: 20 × 80 mm, quad-width/4 × 1 slots
- V-slot beveled lips for guide wheels, including OpenBuilds 2020/2040
- Type B/Bosch-compatible or Type I/Item-compatible profile
How to recognise it
Recognized by a 20 mm square cross-section (or multiples like 20x40 mm) with a centered 6 mm to 6.4 mm wide longitudinal groove opening on one or more faces leading into an internal widened T-shaped channel.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| V-slot 20-series | V-slot features chamfered outer lips at 45-degree angles to act as a dual linear rail track for V-wheels, whereas standard T-slot has flat perpendicular or 90-degree square opening shoulders. |
| Series 10 (1-inch fractional T-slot) | Series 10 is imperial (1.0 inch / 25.4 mm profile, ~0.25 inch slot) while 20-series is metric (20 mm outer grid with 6 mm slot). |
| 2020 V-slot | V-slot features chamfered/angled lips along the slot opening designed to act as a linear guide track for V-wheels, whereas T-slot has flat, square interior lips. |
| 10-series (1 inch) 80/20 T-slot | 10-series has a 1.0 inch (25.4 mm) profile width and roughly 1/4 inch slot, whereas 2020 is metric 20 mm x 20 mm. |
| 1515 T-slot or 3030 T-slot | 1515 is 15 mm x 15 mm with a narrower slot; 3030 is 30 mm x 30 mm typically with an 8 mm slot. |
Also called
20-series extrusion slot6mm T-slot channel; 6mm T-slot femaleEuropean standard 20 series aluminum extrusion profile; 20 Series 2040 aluminum extrusion2020 T-slot channel; Type B / Type I 2020 T-slot20 series slot 6EU 2020 aluminum extrusion slot2040 T-slot extrusionSlot 6 2040 profile
Good to know
Commonly referred to as European standard 20-series extrusion. While most European 20-series extrusions utilize a 6 mm slot opening, some proprietary systems (like Item System 5) use 5 mm slots, so slot throat dimensions should be verified.
Related connections
Design with real parts
Crafti checks which parts connect, right in your browser.