Connecting BOB one axis to 2 stepper drivers

[Neale]

I'm not sure of the exact parameters of the hardware you are using, but typically putting two driver inputs in parallel will not guarantee that each driver will reliably see each pulse from the BOB. BOB outputs usually have an opto-isolator, and so do driver inputs. An opto-isolator in crude terms is an LED which needs a certain current to turn it on. That pulls down the voltage across the input terminals which might then be too low for the other LED to operate in parallel. If you really want to operate two opto-isolators from a single signal, you could wire them in series so they have the same current through them. But that means a higher voltage from the BOB would be needed and what this should be gets a bit more complicated. It's really a lot safer to use the X+A approach - this is exactly why it is there, and also allows independent homing of the two motors (as you cannot guarantee that they will stay exactly synchronised for ever, however carefully set up).

[Noplace]

Thank you, I appreciate you explaining it thoroughly :)