[msisk6]

These aluminum extrusions are called T-Slot, or as McMaster-Carr calls it, "T-Slotted Framing". Very common in industry; we have it everywhere on the Boeing factory floors. Not cheap, but very durable and reusable. Highly recommended.

Check it out starting on page 2240 of your McMaster-Carr 132 catalog. They have all kinds of things you can mount up like monitor arms. It's an erector set toy for engineers. ;)

[jmarcher]

https://www.mcmaster.com/products/t-slot-framing-components/...

[johnwalkr]

Misumi sells it, and they have an online tool to configure almost anything you want in 3D, including brackets of your choice, fasteners and accessories (like panels, hinges and handles). Then, you can order all of the parts to make your creation with 1 part number.

Makerbeam is also nice, they sell a 5x5mm, 10x10mm and 15x15mm version (normally the smallest cross section of t-slot is 20x20mm). The 5x5mm version is comically small when you hold it in your hand. When you order a set, it comes with tweezers to pick up the screws which are size M1.2.

[seany]

It's often called 8020 aluminium if people are looking for alternative vendors.

[anitil]

Always a good day when I get to look at the McMaster catalogue

[p2hari]

Do we have something similar to McMaster-Carr in Europe. I am looking at maybe Germany, Denmark, Sweden , North Europe and Scandinavia?

[zihotki]

Similar - no (I'd be glad to be proven wrong), but you can find some small suppliers focused on specific niche like https://www.motedis.com if you need the profiles.