Following up from this great resource (How to calculate V-Slot® deflection) to calculate deflection, what is a good deflection to shoot for? It looks like assuming a 10kg load, the 750mm C beam router (C-Beam Machine XLarge) is calculating out to about 0.03mm of sag in the middle of the space. Actually a related question, the link is saying 0.140mm, which is using the horizontal moment of inertia, not the vertical which would be from the weight of the Z axis and router. Is this assuming a 10kg cutting force? Assuming this is correct, would a good design aim to be under 0.14mm of deflection in both directions? The reason I ask is I have been working on a 850mm gantry design, as a good middle ground between rigidty/price/cutting width (plus it has successfully been done before on rigid machines), with the intentions to get up and running and then expand to a 1500mm gantry so I can slide full sheets of MDF through eventually, but am questioning myself if I should just jump into the design of a 1500mm wide gantry from the get go so that I wont have to buy parts, and un/reassemble multiple times. As usual thanks for all the input guys!