Holes that qualify as âdeep-hole drilling are three or more drill bit diameters. deep. When drilling this deep, the speed and feed rate must be adjusted to. reduce friction. Friction creates heat, and heat build-up in the drill bit can cause. failure and breakage. Lubricants help dissipate heat from the tip of the drill bit, prolonging drill life, and should always be used when deep-hole drilling.
Humphry's Peak (not to be confused with Mt Humphrey's in the Sierra) in the Coconino National Forest, is the tallest summit in all of Arizona. It is part of the San Francisco Peaks, a volcanic mountain range 9 miles north of Flagstaff, Arizona.
Area code 928 in Flagstaff, Arizona, is also home to Mount Humphrey, which peaks at 12,643 feet as the highest mountain in the entire state. The Flagstaff area code split off from the 520 area code in 2001. It also covers the touristy Grand Canyon and the quaint town of Yuma, Arizona.