Hi All

In another post regarding a new build, one of the contributors commented:

If you are using two screws and two motors you will have to use two home switches to make sure the gantry is put square every time you home.

You can of course use two screws with one motor and a belt driving both screws then one home switch will be fine.

This might be another example of "the blindingly obvious", but to me it's not......yet!


This was a moving Y gantry machine.


If the machine was well designed for maximum rigidity, and accurately built with good quality components (as best this can be achieved in "home" circumstances), why does it go "out of square" such that "squaring" is necessary?

I can only think that it might be caused by one motor missing a step.......but then why doesn't the gantry resume "squareness" naturally when the system is powered down?


But this suggests that in a single motor, twin belt drive moving gantry machine, the gantry always remains square?..........does it?


Then I wonder what is regarded as "square" or unacceptably "out of square"?

5um/m, 50um/m?


Can someone explain and put this into perspective for me please.


Many thanks

Martin