Cabinet building is easy with aluminium angle and wood from the DIY store. The advantage of building a box for your equipment compared to buying a box, is that suitable enclosures are very hard to find. When you do find a box the right size, it is invariably very expensive. By building your own, you get exactly the size you want, when you want, and not too expensive!
Here some raw materials: pieces of aluminium angle from the DIY store and a strip of 1/4-inch (6mm) pine.
These particular pieces were used to construct the cabinet for my polyphase method receiver. The aluminium angle was bolted together to create a frame, which the wood sections were screwed onto. The front panel is made of a piece of aluminium sheet (also available at the DIY store).
Extensive use of aluminium angle again, in my TinyScope miniature all-valve oscilloscope project. Here aluminium angle is used to fix on the steel mesh sides of the cabinet. The steel mesh allows heat to escape the compact enclosure but prevents accidental access to the high voltage components inside. The steel mesh is also from the DIY store.