This is a full redesign of my popular, but old and relatively weak spool holder that I designed nearly two years ago... Old, Obsolete Spool Holder: http://www.thingiverse.com/thing:290064 Here's a video of me explaining everything you need to know about the redesign... https://www.youtube.com/watch?v=cyQ8u1Kn0mM&feature=youtu.be This new design is 100% better - I completely redesigned my screws and spinner bolts for better tolerance for 3d Printing... My old screws were good if they were machined, but they were way too fine to be 3D printed well... So I made the threading much better and made the screws much stronger... I also added a lot of structural features that I explain in the video... Here's a list of what I did in the new design. Made both arms (the base and the spinner) 2.5mm shorter in height, I also added fillets to every corner so every contour is nice and rounded. Redid the bolt pattern and made that easier on the hand while spinning the spinner bolt. Increased the diameter of the screws and added 45 degree chamfers for strength... Screws are very strong now. Redid all the threading... This will thread smooth and tight right off the printer - I had 100% success rate on prints. Added a hole on the lower Rods to hold ends of filament to keep them from unraveling or raveling in - resulting in getting the spool tangled up. This is now about a 33% decrease in total print time from my old design... Overall, it should take about 6-7 hours to print an entire holder on a standard .2mm layer setting... But you can speed it up by going .3mm and everything will be perfect... Infill is not a big issue... 15-20% should do it... If you want everything to look nice on the outside - do 3 perimeter shells. Other than all of that - this should work for everyone and will fit on 95% of spools... The only two spools that I know do not fit are Makerbot's newer long, skinny spools and Taulman spools... Which I actually made a spool holder specifically for... You can find the Taulman spool holder here... http://www.thingiverse.com/thing:938437 **I hope you find this spool holder useful... Thanks for reading... ENJOY!!!