A modern core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core.
Truck-mounted core drill
Core drills used in metal are called annular cutters. Core drills used for concrete and hard rock generally use industrial diamond grit as the abrasive material and may be electrical, pneumatic or hydraulic powered. Core drills are commonly water cooled, and the water also carries away the fine waste as a slurry.[1] For drilling masonry, carbide core drills can be used, but diamond is more successful when cutting through rebar.[2]
The earliest core drills were those used by the ancient Egyptians, invented in 3000 BC.[3] Core drills are used for many applications, either where the core needs to be preserved (the drilling apparatus used in obtaining a core sample is often referred to as a corer), or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit. This is the reason that diamond-tipped core drills are commonly used in construction to create holes for pipes, manholes, and other large-diameter penetrations in concrete or stone.
Core drills are used frequently in mineral exploration where the drill string may be several hundred to several thousand feet in length. The core samples are recovered and examined by geologists for mineral percentages and stratigraphic contact points. This gives exploration companies the information necessary to begin or abandon mining operations in a particular area.
An oriented core goniometer, commonly used when analyzing cores for contacts and other structural features
Before the start of World War Two, Branner Newsom, a California mining engineer, invented a core drill that could take out large diameter cores up to 16 feet in length for mining shafts. This type of core drill is no longer in use as modern drill technology allows standard drilling to accomplish the same at a much cheaper cost.[4]
Core drills come with several power choices including electric, pneumatic, and hydraulic (all of which require power sources, such as a generator).
Wireline core drillingedit
Wireline core drilling is a technique used to extract the core without having to retrieve the entire drill tube, which generally only needs to be retracted when the hole is finished or the tip must be replaced. Drill tube extensions are added at the top as required to extend the tube as the hole gets deeper. The core sample is carried by an inner tube locked in place in contact with the drilling head, To recover the core, the drive system is disconnected, opening the top of the tube. A tool called the overshot assembly is lowered at the end of a wire using the retraction winch, when it reached the sample tube, it locks onto the top, and applying tension to the wire unlocks the sample tube from the drill head and retracts it and the core sample to the open top end of the drill tube, where it can be removed before returning the sample tube down the drill tube to lock back onto to the cutting head. This is particularly useful if there is a high risk of the hole walls collapsing when the drill tube is retracted, so it is suitable for most soil types, and to depths of 1000 m. Several diameters are available.[5]
This section needs expansion with: Sectional diagram of the core removal system. You can help by adding to it. (March 2022)
^"Diamond Core Bits vs Carbide Core Bits". 10 December 2012. Retrieved 4 August 2014.
^"Concrete Drilling Tutorial". Retrieved 4 August 2014.
^Jacques W. Delleur (12 December 2010). The Handbook of Groundwater Engineering, Second Edition. Taylor & Francis. p. 7 in chapter 2. ISBN978-0-8493-4316-2.
^Boone, Andrew R. (December 1943). "He Bores Bigger Holes". Popular Science: 104–107.
^"Wireline coring". Parma, Italy. Retrieved 17 March 2022.
January 01, 1970
core, drill, modern, core, drill, drill, specifically, designed, remove, cylinder, material, much, like, hole, material, left, inside, drill, referred, core, truck, mounted, core, drill, used, metal, called, annular, cutters, used, concrete, hard, rock, genera. A modern core drill is a drill specifically designed to remove a cylinder of material much like a hole saw The material left inside the drill bit is referred to as the core Truck mounted core drill Core drills used in metal are called annular cutters Core drills used for concrete and hard rock generally use industrial diamond grit as the abrasive material and may be electrical pneumatic or hydraulic powered Core drills are commonly water cooled and the water also carries away the fine waste as a slurry 1 For drilling masonry carbide core drills can be used but diamond is more successful when cutting through rebar 2 The earliest core drills were those used by the ancient Egyptians invented in 3000 BC 3 Core drills are used for many applications either where the core needs to be preserved the drilling apparatus used in obtaining a core sample is often referred to as a corer or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit This is the reason that diamond tipped core drills are commonly used in construction to create holes for pipes manholes and other large diameter penetrations in concrete or stone Core drills are used frequently in mineral exploration where the drill string may be several hundred to several thousand feet in length The core samples are recovered and examined by geologists for mineral percentages and stratigraphic contact points This gives exploration companies the information necessary to begin or abandon mining operations in a particular area An oriented core goniometer commonly used when analyzing cores for contacts and other structural features Before the start of World War Two Branner Newsom a California mining engineer invented a core drill that could take out large diameter cores up to 16 feet in length for mining shafts This type of core drill is no longer in use as modern drill technology allows standard drilling to accomplish the same at a much cheaper cost 4 Core drills come with several power choices including electric pneumatic and hydraulic all of which require power sources such as a generator Wireline core drilling editWireline core drilling is a technique used to extract the core without having to retrieve the entire drill tube which generally only needs to be retracted when the hole is finished or the tip must be replaced Drill tube extensions are added at the top as required to extend the tube as the hole gets deeper The core sample is carried by an inner tube locked in place in contact with the drilling head To recover the core the drive system is disconnected opening the top of the tube A tool called the overshot assembly is lowered at the end of a wire using the retraction winch when it reached the sample tube it locks onto the top and applying tension to the wire unlocks the sample tube from the drill head and retracts it and the core sample to the open top end of the drill tube where it can be removed before returning the sample tube down the drill tube to lock back onto to the cutting head This is particularly useful if there is a high risk of the hole walls collapsing when the drill tube is retracted so it is suitable for most soil types and to depths of 1000 m Several diameters are available 5 This section needs expansion with Sectional diagram of the core removal system You can help by adding to it March 2022 See also editCore drills annular cutters for metal drilling Drilling fluid Drilling rig Exploration diamond drillingReferences edit Diamond Core Bits vs Carbide Core Bits 10 December 2012 Retrieved 4 August 2014 Concrete Drilling Tutorial Retrieved 4 August 2014 Jacques W Delleur 12 December 2010 The Handbook of Groundwater Engineering Second Edition Taylor amp Francis p 7 in chapter 2 ISBN 978 0 8493 4316 2 Boone Andrew R December 1943 He Bores Bigger Holes Popular Science 104 107 Wireline coring Parma Italy Retrieved 17 March 2022 Retrieved from https en wikipedia org w index php title Core drill amp oldid 1188532041, wikipedia, wiki, book, books, library,
