Original MIDI size 3D Assembly Square

Make square assembly fast, accurate, and stress-free.

Designed and used daily in our professional furniture workshop, this British-made jig is a proven game-changer for building bookcases, cabinets, kitchen units and more.

IMPORTANT: After initial push-fit assembly, all screw holes must be piloted to the full depth of the screw using a 2.5mm or 3mm diameter drill bit (not included).

Why it works

• Holds parts perfectly square in 3 dimensions for precise screw-fastening.
• Eliminates marking out, dominos, Lamello, or complicated joint prep.
• Saves time and increases accuracy whether you’re a DIYer or trade professional.
• Unique corner design gives clear visibility for lining up edges and marking reference lines.
• Works seamlessly with Festool, Makita-style rail clamps, and most Irwin clamps.

Latest Upgrades

• Extra clamping slots for upside-down benchtop use.
• Re-shaped mid braces for easier assembly.
• Clean, flat side surfaces (no recessed logo).

Perfect for DIY & Trade

DIY: Makes tough jobs simple with minimal tools.

Trade: Boosts efficiency and profit both in the workshop and on-site.

Workshop-Tested

At Freebird Interiors, we've used this jig concept for many years before refining and improving it for CNC production and sale to you. 

We still regularly use this jig in our 2600 sq ft Sheffield workshop, alongside CNC, Lamello, Festool and Mafell tool systems - because sometimes, this simple tool is still the most efficient solution.