This reinforced internal corner connector is designed for 40×40 T-slot aluminum extrusion profiles, providing a strong, compact 90° internal joint while maintaining a clean exterior.
It fits neatly inside the corner grooves, allowing you to join two profiles perpendicularly without external brackets.

Features:

🧱 Reinforced geometry for improved rigidity and load-bearing strength

🔩 Friction-fit mounting — slides smoothly into the T-slot and locks firmly in place

⚙ Compatible with most 4040 systems (Bosch, Item, Motedis, OpenBuilds, etc.)

🖨 Prints flat, no supports needed

🔧 Ideal for rigid internal joints in CNC frames, printers, enclosures, and modular assemblies

If your extrusion brand has slightly different internal dimensions, adjust tolerances by ±0.1–0.2 mm for an optimal friction-fit.