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

[irving2008]

I've thought about it.... if only I had the time....

[m.marino]

Irving,

Your not the only to do some serious thinking about it but the time and resources to put it together proper is no small matter. Just setting up the tables and getting photos of different design set ups to show the pluses and minus of each and where they can be used and how they are applications of different formula is a nightmare. It would be extremely useful to folks wanting to build and understand as well as students of the mechanical and electrical principals just a headache in the making and very time consuming. Have a good portion of the data, just not the time to put it all together and get the other information that is need to make it work.

Michael

[martin54]

This will sound negative but I doubt if there are to many people who really care about the why's. I don't mean to sound negative but from what I see from looking about most forums (not just cnc) all people want is to know how to make it work, not the reasons behind how they could figure it out for themselves.
If there were more people like DC about & this sort of question got asked a lot on forums then I would have thought someone would have done something about it before now. Not saying it would be a waste of time to do, just don't think it would get the amount of use some people think it might get.

[JoeHarris]

Why don't we do it as a team effort on here through a thread. Use a post per design with honest +\-. If we had one thread with pictures and info on lots of machines it would be an amazing resource for those of us still designing. Spread the effort about! Then it could be compiled...

[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...

[martin54]

Perhaps it would be possible to do both the same way some websites are constructed where there is little detail about an item upfront for those that already know or aren't interested but with more detail deeper within the site for those that would like to know more.
Doesn't really matter how it is done as long as someone who knew what they were doing would agree to take the lead and monitor the thread & control it's direction. Would be useful a a sticky somewhere for people who were new to the site as well as helping some of us who are already members.

[D.C.]

Perhaps doing it online in a wiki form would help, it spreads the workload out and can be imroved by more people that way.

I agree that most people just want something to work, but the number of horror stories and people getting hugely stressed about things not working and not understanding why they don't work I think shows that such a resource would be useful. While ploughing through the forums I came across a similar sentiment of "If a machinist can't fix his own machine he isn't a machinist". People don't really decide to build their own car without expecting to learn about being a car mechanic and how internal combustion engines work so why try to reduce cnc to the level of understanding that is required to assemble a table from Ikea?

[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.