Im currently using a eShapeoko CNC with dual Y Steppers for Milling with Mach 3 via Parallel Port.
Software and Electronics are setup so that the 2nd Y Stepper has its own Limit Switch and Homing also Squares the Gantry.
The next Step on my List is Setup the Machine for 3D Printing.
Ive got a DIY Version of the Gen7 Electronics where i want to do the same.
But im far away with my knowlegde to be able to implement a 2nd Y Limit Switch to the Firmware ( Teacup or Marlin ).
So maybe someone allready did that or is able to help me with this Problem.
( Is it even possible? What about the Host Software? )
All help is appreciated.

Edited 2 time(s). Last edit at 10/26/2014 06:29PM by Ironaxe.

I'm in the same boat. I'll let you know if I figure it out.

I'm looking for this solution too, but at the moment (March 2017) Marlin does not support DUAL Y endstop feature, only Z axis dual stop is supported.

So, there is a very simple work around for this. Mount two switches and wire them in series (they have to be mechanical switches, otherwise electronics would be more complicated). The effect of this is this: Marlin will only consider Y homing complete once BOTH switches deploy. This will cause a slight sliding of one of your motors, but that's not a very big problem, I think. At least if they aren't WAY off.