I certainly don't want to garner any animosity or disrespect by using the word "toy", but the reason for my comment was twofold

1. From your comments I assumed you wanted the cnc machine to do the required job of making guitars. I have made quite a few guitars among other things and I know the amount of rigidity and spindle power that is required to do the job and in a timely manner. You could build a lighter machine that would probably work but you might be dissatisfied with the result so I'm trying to encourage you to avoid that.

2. I'm assuming you want version 1 of the cnc machine to do the job rather than embarking on a version 2 later, why do you think others have had to build a version 2 ?

If you want to build a cnc machine for learning purposes then Neale's reply might be more applicable. Best of luck either way.

A search on the internet for "cnc schematic" produces loads of hits.