I don't think you have anything to patent with the backhoe design.
You can copyright the plans and files for CNC cutting. That is basically asking people to not turn around and sell them as their own. It is expensive to enforce if they try to sell them anyway. Government does very little to enforce either patents or copyright, it is your expense to bring a civil suit and in most cases your damages are too minor to warrant the expense.
Mr. HE
Good points, Mr. HE. I have some experience that might help BFreaky, having patented several devices and also copyrighted a few designs in my career. In both processes I learned more about them than I ever really wanted to know. Yes, I agree that both processes vary widly from one country to the next.
Even definitions of what is and isn't patentable varies. In general, a patent is description of a unique way of doing something that represents an improvement on current practice. Copyrights differ in that they are more oriented towards works of art or design. And yes, both can overlap. Patents are juried - that is, before being issued they are required to be reviewed by a peer group. A copyright is not juried; anyone can simply put the symbol on his own work that says to the world that this artist wants to retain his own exclusive ownership of his own original work.
A patent has a humanitarian orientation in that it is intended to grant the patentee a defined period of exclusive use of the improvement in exchange for which the patentee agrees to publish that improvement so that anyone can use it.
Copyrights have a less well defined period of exclusivity, are more self-serving as they don't carry any obligation to make the work public property.
All of this is vague because of the different ways that different countries view both processes. And that changes over time as well. As Mr. HE points out, many governments do little or nothing to enforce either one even to their own citizens - and even less for anything of foreign origin. There may even be countries where foreign patents and copyrights are not recognized as exclusive. If so, it would be quite legal for people in that country to sell copies of any work without any obligation toward the inventor/artist.
So, the lack of enforcement is quite common. Expect it. Several otherwise modern countries don't even make a pretense.
IMHO, if you do want to sell plans your best bet is to copyright your work and then to advertise that you will provide good plans for a fair price. I know that sounds to simple to be good advice, but personal popularity and integrity are still just about the best protection any artist can have...... and both are free. For that matter, the entire copyright process itself is free - since it is just a symbol along with your name and a date all intended to signify that your intent is to retain ownership of your work.
Your copyright also keeps someone else from being able to copy your work and then denying your authorship.......that being one of those odd and quixotic possibilities that can be entertaining to ponder.
Best of luck with it,
rScotty