Joinerers v1.0

Used to join 25.4 mm / 1 inch square extruded aluminium together in various ways to make frames (generally sold in standard lengths in hardware stores or metal suppliers - e.g. known as Qubelok or Connect-IT in Australia). These connectors are designed to be printed flat without supports to improve printing times and avoid clean-up for rafts - so they aren't perfectly "cubic" as a result (to avoid overhang).

The use of aluminium extrusion square tubing allows for larger frames to be created - test out various degrees of in-fill or shells to see *if* it is strong enough (as with any 3D printed part that needs to take load).

Unlike the limited options for commercial joining pieces - by creating a 3D printed version (aka "Joinerers") there are a wide range of additional pieces and you can do funny angles if you need, hence the name "Joinerers" - for all those weird joinering needs!
All the standard things like 90 degree connectors (elbow, Tee, Cross, corner and intersection type