Assembly Assistance for the Printrbot Simple - 3D Printing: Build your Own 3D Printer and Print your own 3D Objects - page 41

Early Assembly Observations
In the first few steps, you assemble the base of the Simple. You see how to connect
bearings to one of the larger laser-cut pieces. The bearings have a slightly greasy
feel because some oil has been applied to them for lubrication. Later you'll insert
metal rods through the centers of the bearings, and the lubrication will allow them
to slide back and forth easily. Figure 3.4 shows that I've got all four bearings at-
tached to the wooden piece with zip ties. Notice that I haven't yet clipped the zip
ties like the ones shown in step 2 of Figure 3.2 . I'll clip them before moving on to
the next step.
Figure 3.4 Metal rods will be inserted into bearings (underneath the wood piece).
Note
If you look back to Figure 3.2 , notice that the BOM describes the bear-
ings with a part number—LM8UU. Fortunately, all the bearings in-
cluded in the Simple kit are labeled. You have to look carefully, but the
part number is visible on the rubber gasket that's inserted inside one
end of each bearing.
Many 3D printers use aluminum rails or other materials to form a base. Instead
of zip ties, these types of materials often require nuts and bolts to lock everything
down. Part of the low cost of the Simple is found in the materials, such as the