Deep hole drilling is a machining process that can produce holes up to ten times deeper than the diameter of the hole and is suitable for a variety of metals, including the strongest of superalloys. Deep hole drilling services require special tools and setups to deliver high-pressure coolant, cleanly evacuate chips and reach the depth-to-diameter. Deep hole drilling, also known as gun drilling, is a highly-specialised machining operation that only a few engineering companies can perform, including PRV Engineering. Here is a closer look at some of the processes, applications and pros and cons.