Wegener also noted that the continents move up and down to maintain equilibrium in a process called isostasy. As an example he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago.
Drill that is fitted with a Pipe provides effective connection to the rig surface equipment or application with the bit and the bottom hole assembly for the purpose of pumping the Drill fluid to the bit.
Hammer drills are regularly used by contractors and professionals to install electrical boxes and other fixtures to brick and block walls. DIYers and homeowners also use hammer drills for many types of projects, with the most common being the installation of shelves and cabinets on masonry.