Screw Quad Extension
thingiverse
The screws are the smoothest 3d printed ones i've found. Going to use it as a lead screw for a cheap 3d printer but they're not long enough. These screws SHOULD attach together.
Download Model from thingiverse
With this file you will be able to print Screw Quad Extension with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Screw Quad Extension.