Drilling a hole deeper than 4 to 5 times its diameter is considered deep hole drilling. Dearborn has built our business and reputation dating back to 1947 on our precision gundrilling expertise and technology. Our ability to deep hole drill ferrous and non-ferrous specialized metals and alloys is unprecedented. In fact, we can drill ultra-deep holes, with a potential depth-to-diameter ratio of 600:1 possible depending on material and hole size requirements. This is an example of the unrivaled precision that Dearborn consistently provides to our clients.