Hi, I am not an expert, but I will throw some basics on the table FWIW. I am sure others will throw in their ideas.
Let's suppose you want to use a NEW Haas mill to do the work
- For the mill and setting it up - about 100K
- Tooling for specific tasks - about 15K
- Software for designing about 15k
- Quality experienced machinist about 80K year including overhead, benefits
Can you go cheaper- sure - maybe 1/2 of that if you shop carefully.
You might even find a machinist locally that is willing to set up a shop in your building and exchange rent for parts, depending on if you have that much room.
I think the main driving force for bringing machining in-house is for more rapid turn around and quick testing of ideas. It is hard to justify internal capability on a pure cost savings aspect. Of course, that has not stopped many hobbiest from buying and building mills and cnc routers.