The models come in different sizes. I uploaded diameters of 4mm, 5mm, 6mm, 8mm, 10mm and 12mm each in a 150mm, 200mm and a 250mm version. If you are not sure, wich one to choose, just get the 8mm x 200mm version, it is a good place to start.
These simple knitting needles are printed in two parts and are then jointed together using some short 1,75mm filament-strips that act as dowels. That makes them easy to print laying down flat on your printbed.
If you want, you can add some glue and/or give them a sanding to make them even smoother after putting them together. Therefore it is the easiest way to ut them in a dril and turn them while using the sand paper.