Assembly Assistance for the Printrbot Simple - 3D Printing: Build your Own 3D Printer and Print your own 3D Objects - page 52

Figure 3.14 Use a zip tie to hold the vinyl tubing to the lead screw.
You then insert the open end of the vinyl tubing over the Z-axis motor and use an-
other zip tie to hold it in place. Get that zip tie good and tight, as shown in Figure
3.15 . Spin the lead screw with your hand; if the motor axis turns easily, cut the tail
on the zip tie. Otherwise, tighten the zip tie a bit more.