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An underground rocket or rocket drill is a device for rapidly drilling holes through soil and rock of varying composition at rates up to 1 metre per second [1] [2] by utilising supersonic jets of hot gases. It was developed by Russian engineer Mikhail Tsiferov in 1948.
The drill was contracted due to the lack of machines capable of breaking up the caliche-laden sedimentary rock present in the region. In addition, it was also used in the construction of the Blue Diamond Road flyover. [1] Later that month, Big Stan was used to drill the foundation for the Gold Line basket bridge in Los Angeles, California. [11]
Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multi-point. The bit is pressed against the work-piece and rotated at rates from hundreds to thousands of revolutions per minute.
Modern gun drills use carbide tips to prolong life and reduce total cost when compared with steel tips. Speed of drilling depends on the material being drilled, rotational speed, and the drill diameter; a high speed drill can cut a hole in P20 steel at 75 centimeter (30 inches) per minute. Gun drilling can be done on several kinds of machine tools.
11. A memory phone can store photos with names and contact information. 12. Puzzles and activity books stimulate the brain and promote cognitive sharpness.. 13. Card games and board games ...