Sewing Thread Carousel in CD Spindle

My daughter asked me if I had some idea how to store the many sewing thread spools and corresponding machine bobbins which started to accumulate since she got her new sewing machine. Fortunately I never threw away my empty CD/DVD spindles, always thinking that "some day" I will find something useful to do with them...

So this little project builds a carousel for storing sewing thread spools inside an empty 50-CD/DVD spindle. :)

The carousel consists of a round base plate for two concentric rings of spools and the corresponding number of spears onto which the thread spools are stuck.

The spears are mounted on the base plate by sliding them into the corresponding rails. The top of the spears is hollow and acts as a compressible clamp for retaining a machine bobbin for the lower thread of the same color as the main spool on this spear. Given that the clamp need to have some flexibility, ABS is the material of choice for this project.

The SCAD source is fully param