I’m building my new 3D printer and I have a doubt. I’m using limit switches on the 3 axes, but only the MIN switches. I also have another three switches which I want to use as MAX switches. How can I do that? I mean, if I insert a specific measure of the plate in Marlin and than the extruded stops before of the limit of the plate due to the MAX endstop what will happen? What should I do, upgrade to MIN and MAX endstops or only keep the MIN ones?

  • $\begingroup$ Most boards lack contacts for MAX. $\endgroup$
    – Trish
    Commented Apr 25, 2020 at 7:48

1 Answer 1


You should see MAX endstops similarly as MIN endstops, or as an additional option to protect the printer:

  1. Similarly seen as MIN endstops, you would define in the firmware that you are using them to set a reference point at maximum values, your offsets and bed dimensions would be calculated from the MAX positions;
  2. You can configure the MIN endstops and have additional MAX endstops set beyond the bed size dimensions. If the printer would encounter a layer shift causing the nozzle to go beyond the printer (MAX) boundaries, the printer shuts down when the MAX endstop is triggered.
  • $\begingroup$ Ok, thanks. So i can’t use both of them in one axis? I think i’m going to use only the MIN ones $\endgroup$
    – Valeri 0S
    Commented Apr 27, 2020 at 6:06
  • $\begingroup$ @Valeri0S As explained in the answer under 2. You can use them both. But don't put them at exactly at the maximum axis positions according the bed size, put them a little further, then they will act as safety stops in case of layer shifting occurrences. $\endgroup$
    – 0scar
    Commented Apr 27, 2020 at 6:19

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