I promise I will stop asking daft question soon. Ish.

[irving2008]

Hmmm... I think there are lots of different ways of approaching this... my thinking was more theoretical in terms of how to actually do the formal assessment of a design, rather than the comparative assessment of a specific build v another specific build. Don't get me wrong there's a lot to be said for the crowd view but there's always some subjective opinion. I think the issue raised by DC is one of "with all the helpful but diverse input how does he make a reasoned assessment, what are the basic parameters he needs to understand", at least in sufficient detail to get a feel for things, and, IMHO, that needs an element of the 'why' about it. For some people that could be intuitive, they can look at something and see how it might behave, others need to see the numbers and yet others need pictures...

[D.C.]

I think the issue raised by DC is one of "with all the helpful but diverse input how does he make a reasoned assessment, what are the basic parameters he needs to understand", at least in sufficient detail to get a feel for things, and, IMHO, that needs an element of the 'why' about it. For some people that could be intuitive, they can look at something and see how it might behave, others need to see the numbers and yet others need pictures...

I think this is pretty accurate, looking at buiilding a CNC machine my inuition tells me that optimum design would be to make a lightweight but very rigid moving gantry that is supported on four rails inside a structure that is a hollow cuboid. My inuition might be totally wrong, it might be that the extra friction would eliminate any benefits or one of a million other reasons why that might be an awful layout but I lack the engineering knowledge to work it out for myself.

There are loads of books for cars or photography or telescope building etc etc that are aimed at a mechanic sort of level, combination of practical skills and enough of the maths to work things out reasonably well in most circumstances without reducing things to the level of 'insert screw a into hole b' and without bogging things down with doctorate level maths/material science.