The toolhead offsets are only relevant to printers with two extruders. If your printer has a single extruder setup, then ignore this section.
When, however, you have two extruders, the printer must know the spacing between the nozzles. The reason being that, when the printer switches extruders, it needs to know what distance to move the extruder carriage so that, for example, the left extruder is now over the exact position at which the right extruder finished printing. This spacing along the X and Y axes is known as the X and Y toolhead offsets. It is assumed that the two nozzles are at the same Z position, and thus there is no Z toolhead offset. Each printer manufacturer has an “ideal” set of nozzle spacings, which are built into each printer-specific version of Sailfish. However, owing to manufacturing tolerances, your nozzles may not quite be spaced with the ideal offsets. As differences of tenths of millimeters can impact the final appearance of your prints, you can adjust the toolhead offsets to match your printer.
These values may be set from the printer’s front panel as explained in Section 3.7.11. They may also be set from ReplicatorG, MakerWare, and MakerBot Desktop using the “Machine” menus and accessing the onboard parameters. However, there is a simpler method to set the toolhead offsets: print a calibration print. Complete step-by-step directions may be found in Section 5.2.
Additional details on the implementation of toolhead offsets are given in Section 9.2. Look to that section if you plan on making your own calibration prints and need to know, for instance, the sign conventions associated with application of the offsets.