Setting the Z-Axis Home Position


The distance between the nozzle and the print surface is an important factor in print quality. With the bed at the Z home position, the gap between the hot end nozzle and the top of the print surface should be 0.010 inches (about 3 sheets of standard paper). If the gap is too small, the hot end nozzle will either contact the print surface or squish the first layer, potentially making your print difficult to remove from the bed. If the gap is too large, the first layer of plastic will not adhere to the print surface adequately. This article will guide you through the process of setting the Z-axis home position for the ideal first layer height. 

Tools Needed: 

  • 4mm Allen key
  • 8mm wrench
  • Calipers or micrometer
  • 0.010" feeler gauge or 3 sheets of standard paper


  1. For GB2, adjust the Z home position using the Z-axis limit switch screw, found on the right rear corner of the bed frame. For GB3, the screw is located on the right front corner of the bed frame. Adjust this screw using a 4mm Allen key.
  2. Ensure the M5 x 65 screw (M5 x 70 for GB3) is inserted into the Z-axis limit switch block with the head sticking up about 50mm above the block, and the lock nut (GB2 only) is tightened.
  3. Position the extruder and hot end at the rear of its travel (Max Y position).
  4. When homing the Z-axis, ensure the hot end does not come into contact with the bed. Manually move the print head to the very front or back of the machine so the nozzles are not above the bed. You can also manually stop the bed motion by triggering the Z-axis limit switch with your finger.
  5. Using the Pronterface or Simplify3D control panel or the Viki, press the Home Z-axis button.
  6. Adjusting the M5 x 65 (M5 x 70 for GB3), lowering the screw will raise the bed higher (closer to the nozzle), and raising the screw will lower the home position (further from the nozzle). Ensure the lock nut (GB2 only) is tightened after adjusting the limit switch screw.
  7. One revolution of the screw will change the bed height 0.8mm (0.031").
  8. Use a 0.010" feeler gauge or 3 sheets of paper to gauge the distance between the nozzle and the bed. Keep adjusted the screw and homing Z until there is slight friction on the feeler gauge or paper between the bed and nozzle.
  9. The photo below provides a visual reference for what your first layer should look like. 

Bed Height

For GB3, the screw is located at the front right corner of the bed frame.

GB3 3 Adjust

File: Z-axis Alignment Tool

For initial calibration, please proceed to the next calibration step (Select Single or Dual depending on your extruder type): Single Extrusion Calibration | Dual Extrusion Calibration

Questions or concerns? Reach out to our support team at or open a support ticket.  

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