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A horizontal boring machine or horizontal boring mill is a machine tool which bores holes in a horizontal direction. There are three main types — table, planer and floor. [1] The table type is the most common and, as it is the most versatile, it is also known as the universal type. [2]
The machine began excavation of the 1.7-mile-long (2.7 km) route on July 30, 2013, with completion of the bore scheduled in 14 months' time and the tunnel opening to traffic in December 2015. [ 24 ] [ 25 ] [ 26 ] Over 5,000 members of the public, along with Governor Jay Inslee , were present for the machine's dedication a week prior to the ...
Directional boring machine. Directional boring, also referred to as horizontal directional drilling (HDD), is a minimal impact trenchless method of installing underground utilities such as pipe, conduit, or cables in a relatively shallow arc or radius along a prescribed underground path using a surface-launched drilling rig.
This method of bore finishing is better suited for bores with relatively low length-to-diameter ratios, usually less than 2:1. However, if there are cross-holes, or other interruptions in the bore, then a ratio greater than 2:1 is possible, because swarf and fluids may be expelled via these routes. This process is also not well suited for ...
There are two styles of small-hole gauges: full-ball and half-ball. The full-ball gauges are easier to set correctly and maintain, under the pressure of measurement, a better representation of the bore. Half-ball gauges tend to spring just a little bit, and this may be enough to make a measurement incorrect.
The operator also monitors the surface to ensure it remains undisturbed. As the tool nears the exit point, it is slowed down, and an exit pit is dug to locate both the tool and the bore. As the tool enters the exit pit, the operator chooses to either dig up the tool to retrieve it or reverse it back into the first bore pit for retrieval.
Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal directional drilling - HDD), and surface in seam (SIS), which horizontally intersects a vertical bore ...
Thus very high surface qualities with bore hole tolerances of IT 9 to IT 7 can be achieved by deep hole drilling processes. Subsequent steps to improve the surface quality of the bore hole can often be reduced or eliminated completely. A further advantage is the low burr formation for trough holes and for over-drilling cross holes. [1]