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. ...
I estimate total cost of ownership every time I compare machines for a production application. The purchase price is only part of the picture. Over a ten-year machine life, the operating and maintenance costs often exceed the initial purchase price by a wide margin. The TCO Breakdown That Matters For a mid-size gun drilling machine running two shifts over 10 years, the cost distribution looks like this: Cost Category Percentage of TCO Typical 10-Year Cost (Mid-Size Machine) Purchase price 30-40 percent $150,000-250,000 Installation and rigging 3-5 percent $15,000-30,000 Cutting tools 15-25 percent $75,000-150,000 Coolant and filtration 8-12 percent $40,000-70,000 Power consumption 5-8 percent $25,000-50,000 Planned maintenance 10-15 percent $50,000-90,000 Unplanned repairs 5-10 percent $25,000-60,000 Training and support 2-5 percent $10,000-30,000 I have seen too many shops focus on the purchase price alone. A machine priced 20 percent below the competition but with 30 percent higher tooling costs will cost more within three years. ...