Assembly Assistance for the Printrbot Simple - 3D Printing: Build your Own 3D Printer and Print your own 3D Objects - page 37

While you're there, be sure to download the Bill of Materials (BOM) PDF file so
you can get a complete listing of all hardware included in the kit. Should you pur-
chase the kit (versus the preassembled version), you can use the BOM to verify
you've got all the parts you need to do the assembly.
Printrbot Simple Assembly Part I
The first thing I'm going to do is verify that I have all the parts. I mentioned in
the previous section that the Printrbot website offers a PDF file for download that
contains the BOM. I can use this to make certain I have all the nuts and bolts, laser
cut pieces, motors, and so on. You get the idea.
Figure 3.1 shows the current version of the BOM. Don't go by this one because
Printrbot may occasionally update the Simple and change the parts list. But as you
can see, it lists things such as qty-12 8mm Linear Bearings, qty-34 Hex Nut- M3,
and qty-1 Extruder gear, among others. (Keep in mind, however, that the BOM for
your Simple may very well have changed by the time you're reading this.)