Hi Robert,

That's a BIG undertaking for a first machine so my first job is to try to talk you out of it...Lol

It's a common mistake for new builders to think that building a large machine cannot be much harder than a small machine because let's face it they work exactly the same way don't they, which in theory they do.!

However, the complications of building a large machine are much higher and the work involved is far greater. Error factors multiply greatly so any twist in the frame etc is amplified. So areas of the build like plane alignment that rails etc sit on have to be so much more accurate and as the size increases, this gets harder to achieve without expensive machine work on the frame.
Likewise, Gantry alignment and stiffness all get harder to achieve and again any errors are amplified which ultimately shows up in the accuracy and quality of the cuts.

My advice to you and any new builder is to start small but if you really must have a large machine then don't try to build one as a first machine, instead, look to buy a used machine or an old machine with older electronics and do a conversion on it, because the electrics are often the easy part of a large machine compared to the mechanical side.

Think long and hard if you continue down this road and do lots and lots of research before buying so much as a welding rod because it's very very easy to fail and end up with an inferior machine that costs probably 2/3 the price of buying a machine.

But if you do continue ask your questions and we will answer.