Yes 1mm above with springs compressed. You want room where you can adjust up and down with adjusters if needed. If your springs are tall enough you could even try 2mm.
For the extruder you need to confirm feed direction. What I do is lower the bed, move the extruder to the center over the bed. I then go to the host and heat the extruder to heating temp as it will not move unless hot. I then try to feed filament. If it is running in the right direction you should feel it pull the filament in.
If it is pushing the filament out then the motor direction needs to be changed. if it is not running at all then the motor wiring needs to be checked. Unlike the axis motors, there are no endstops so only motor settings can affect how this one behaves.
Don't forget that once you get all the motors running and the extruder extruding you still need to set the steps per mm to get the correct dimensions and correct feed rate. There are instructions for this all over Google so I won't go into detail on this unless you end up having a specific question. But this is settings that is common for all firmwares. The only thing that will effect this setting is you choice of microsteps. But there are calculators on line that allow you to input that info as well as the desired dimension and what you.
In a nut shell you print a 20 or 30 mm calibration cube that is the same size in all dimensions. Once it is done make a note with a sharpie on it which axis is which and then measure them with calibers. Use the vale you get in the calculator versus the desired value and it will tell you what the steps need to be set for. You just keep repeating this until all your axis are within the desired tolerance.
Getting better than .004 will be near impossible though. So don't expect machine shop precision.
Setting the extruder is very similar. You tell it to extrude X amount and you measure the amount that was extruded. The only thing to keep in mind it that you measure from the input side, not the output.
Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
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