Like many of us, the place where I do my making is quite full and bench space is at a premium.  I have seen a number of freestanding hookup wire dispensers, but I wanted something that I could attach to the shelf I have in my work area, It works quite well for me.  If you use the STL files these are designed for 4.5 mm diamater heat set inserts for the bolt holes, spools with a diameter of 90 mm a rod of 11.5 mm and desk width of 25 mm. However I have included the fusion 360 files and have set the who file up based on parameters that can be changed so that the design can be adjusted for your unique situation given the parts you have laying around.  If you want to access these parameters refer to the image below.