Mr. Westerfeld,
I am interested in your engraver, whether via a set of plans, parts to assemble, or a finished product.
If it was my project, I would sell drawings for making the tool from scratch and a parts kit with assembly instructions, plus a source list for the ancillary pump, fitting, lines, and so on. Maybe an assembled and de-bugged tool. I would sell as many as possible as quickly as possible before the copy cats start selling their own version.
I also wouldn't disclose any more details here until they are ready to sell in order to protect the intellectual property.
A patent is only useful if you have enough money to defend it in court, and with the recent turn in US patent law, the first person to submit the patent application will be awarded the patent whether the IP belongs to that person or not. The Chinese don't care one way or the other.
Even amongst large companies with dedicated intellectual property offices and attorneys on staff, every great idea may not be submitted for a patent, it may be more valuable as an industrial secret that aids competitiveness.