For mounting a dial indicator to the extruder head for precision bed leveling.

How to use it:

Step 1: Home the axis

Step 2: Turn off the printer. You don't want to move the extruder with the controls, the dial will hit the tower before the extruder hits the limit switch.

Step 3: Manually move the extruder away from the tower so there's room for the dial.

Step 4: Remove the fan and insert the dial so that the tabs slide into the slots in the back of the heatsink. Be careful not to put force into the gantry, you do not want to bend that.

Step 5: Raise the bed by turning the screw nearest to the extruder, this should be the front left screw, until the dial stops turning (or slows down significantly). This is the point where the extruder makes contact with the bed. Zero the dial here.

Step 6: Lower the bed until the dial is at 4 thou or 0.1mm. Manually move the extruder and lift the contact stick thing between stops, this keeps it from jiggling around and possibly pushing itself up (not necessary for a glass bed since it's smoother). You can swich it back on and move it with the controls so you can get a continuous view of the level, just be careful not to let it crash into the tower. Do this for all 4 corners, halfway points between the corners, and it's also a good idea to check the center.

Then you're done! You may find that your bed is slightly high in the middle, try to even it out by lowering the corners a thou or two. It could take a couple laps around the perimeter before all 4 corners are level, so just keep going until it's good. You may have more uncompensatable runoff than you were expecting, mine is about 0.2mm but it still prints fine.