New build with recycled parts on a ridiculous budget 120cm*60cm work area

[Neale]

How are you planning to use the dual home switches (Y axis in your case?). Generally you do this for gantry squaring, but only if your motion controller supports this (and not all do!). I don't think that Mach3 can do this either. I have the same problem on my own machine, by the way, and not trying to pick holes in your design. It's just one of those things that isn't obvious until you come to try to do it...

Personally, I home my dual-axis using just one home switch and manually tweak the other side for squaring purposes as my motion controller is no help at all in this area.