I have been on both sides of this decision. I have set up in-house gun drilling operations and I have sent work to specialized shops. Both are the right answer in different situations. The decision comes down to four factors: volume, diameter, depth, and how much your time is worth. When In-House Makes Sense In-house gun drilling works best when the conditions are right for it. Here is what I look for: ...
The Breakeven Volume Rule I advise shops to buy a machine when the annual volume exceeds about 500 parts. Below that, outsourcing is cheaper. Above it, the machine investment pays off within 2-3 years. The 500-part rule is a starting point. The actual breakeven shifts with part size, material, tolerance, and the shop’s existing capabilities. I have seen shops that broke even at 200 parts because they already had a suitable machine and only needed the drilling attachment. I have also seen shops that needed 1000 parts to justify the investment because they needed a complete machine and coolant system. ...