GeoDave’s calculator works very well.
I think you asking how big can you go if you bought my bundle from this site?
Still not a simple answer.
Let me lead with, the smaller the stronger, the stronger the easier it is to use, also the faster you can cut, print ect.
Z-axis I supply 12″ of allthread, so the max you could do is a little over 6″ of travel and that would need about 2 pieces of 15″ of conduit.
So the limiting factor for the X and Y axis is only the belt that I supply. it is enough for 48″ of combined movement, X=24″ and Y=24″, or x=12″ and Y=36″, ect.
Easy numbers would be 4 pieces at 28″ and 2 pieces at 27″.
I made mine from a big square into a smaller rectangle, turns out I only cut really small parts…..Why did I build a machine that could go so big?
If you want exact numbers run that calculator