Best intentions
I think the most intimidating thing about designing your first CNC machine is not missing something - but using a plan or assembly that will not work for our purpose despite how well we think it will. It's not like we all use our machines for the same thing so there must be some basic diversities in design and ideas.
So.. what are some of the biggest mistakes, black holes of cash and time that have been tried and proven to be to ambitious or costly for the hobbiest?
What did you want to cut with your settup but you just can't quite get it right?
Worry about success, failure takes care of itself.