Use either of these two hinges (they have the same dimensions).
National Hardware 3/4" x 1" Solid Brass Hinge, No. N211-326 (pack of 4)
Stanley 3/4" x 1" Solid Brass Hinge, No. 80-3190 (pack of 4)

A browser may be instructed to download these files for non-profit use (e.g. ctrl/click on a Mac). The type S cube is the same as the type A but also has "JAS" printed by the hinge cutout. The cubes can be assembled in the slicer for a single print of all eight cubes.

Mini Cube A (print 2)
Mini Cube B (print 2)
Mini Cube C (print 2)
Mini Cube D (print 1)
Mini Cube S (print 1)

Standard Cube A (print 2)
Standard Cube B (print 2)
Standard Cube C (print 2)
Standard Cube D (print 1)
Standard Cube S (print 1)