Re: Home built machine setup, perpendicularity

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Scott Riddle" <sariddle@l...>
wrote:

> I am looking to put together my own home built CNC machine with
> linear rails and ball screws onto a heavy tube frame. I am trying to
> figure out how to drive the main X axis which will move a gantry
> over the table. I am contemplating using 2 ball screws(smaller ones)
> to drive each set of trucks. This way I can assure no racking
> problems and have increased machine stiffness. My main questions is
> if I go to the 2 screw system and I am using stepper motors how do I
> initially when build this machine get my X and Y axis perpendicular?
> Assuming that each X and Y rail setup is straight to start with.
>

The first thing I think of is to drill 4 holes in a large sheet. then
measure the results.

if your machine is square, all the measurements will be identical.
if you make a parallelagram, then two will be closer and two further.

Dave