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96 lines
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HTML
96 lines
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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<title>CUCC Expo Rigging Handbook: Drilling holes</title>
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<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
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<body>
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<h2 id="tophead"> CUCC Expo Rigging Handbook</h2>
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<h1>Bolt belays - Drilling and placing</h1>
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<p>Once you've decided where to put your bolt, you have to actually physically
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place and set it. The methods used differ substantially depending on whether
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you are using hand bolts (spits) or Hilti HKDS's.</p>
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<p>Before you actually start drilling, it is wise to flatten the surface of the
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rock around the bolt site. This allows the hanger to lie flat against the rock.
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<p>
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Different types of hanger have different footprints. When dressing the rock, use the pointed
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end of the hammer and tap gently, so as not to crack the rock below the
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surface.</p>
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<h2>Power-drills and Hilti anchors</h2>
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<div class="onleft"><a href="../l/bosch.html"><img
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alt="(73k image)" src="../t/bosch.jpg" width="250" /></a></br><span
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class="caption">Using the Drill</br>(click to enlarge)</span></div>
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<p>Since the first cordless hammer drills made an appearance on Expo 1990
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thanks to sponsorship from Bosch, drills have been enthusiastically adopted as
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the best solution for large-scale bolting tasks; some of the fun and games of
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recent years, like the 21-bolt traverse over Gaffered to the Walls in 2003,
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would be unthinkable with hand bolts. However, drills are not suited to use
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with ordinary spits, as the setting process depends critically on the bottom of
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the hole being flat. It is possible to drill a hole part-way with a power drill
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and finish it off by hand, but this is tedious.</p>
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<p>Hence we have found it easier to use Hilti anchors, which are specifically
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designed for use in drilled holes.</p>
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<div style="text-align: center">
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<a href="../../years/1990/hilti1-300.png"><img
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alt="before setting - 1k png" width="530" height="90" style="margin: 10pt"
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src="../../years/1990/hilti1-100.png" /></a><br />
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<b>Hilti HDK spits before and after setting.</b><br />
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<a href="../../years/1990/hilti2-300.png"><img alt="after setting - 1k png"
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width="220" height="94"
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src="../../years/1990/hilti2-100.png" style="margin: 10pt" /></a></div>
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<p>There are two versions of these bolts, the HKD and the HKDS. The latter are
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easier to use, as they have a "shoulder" around the top of the bolt which sits
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against the rock, meaning that the depth of the hole is not important.</p>
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<p>To place a HKDS, drill the hole in the obvious manner until it is deep
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enough for the bolt to sit in without touching the bottom. If in doubt, drill
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it deep! When the hole is deep enough, grab a setting tool and start bashing it.</p>
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<p>Start with very gentle taps. The reason for this is so the shoulder can hold
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the bolt in position until it begins to grip the sides of the hole; if you
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start by smashing it with all your might, the shoulder will bend and the bolt
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will disappear, useless, into the depths of the hole. Once it has some grip you
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can start hitting a bit harder.</p>
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<p>It is very important to hit the Hilti setting tools exactly square, as they
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are made of very hard steel which is rather brittle and hence it is easy to
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shear the end off. When the bolt is fully set, you should be able to see marks
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on the shoulder of the spit from the four little teeth on the collar of the
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driver; don't worry if you can't see all four setting marks, but aim for two at
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least - one can easily be a consequence of leaning the driver over too far to
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one side.</p>
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<p>Sometimes, in particularly hard rock, it can be impossible to get the
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setting marks. Use your judgement; if you're not making any progress despite
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sustained hammering, it's probably OK to stop!</p>
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<hr />
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<div id="menu">
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<ul id="links">
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<li><a href="../index.htm">Expedition Handbook</a>
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<ul>
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<li><a href="../rig/rigit.html">Rigging guide</a></li>
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<li><a href="../survey/index.htm">Surveying guide</a></li>
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<li><a href="../look4.htm">Prospecting guide</a></li>
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<li><a href="../rescue.htm">Rescue guide</a></li>
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<li><a href="../photo.htm">Photography guide</a></li>
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</ul></li>
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<li><a href="../../infodx.htm">Main index</a></li>
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<li><a href="../../index.htm">Expo Home</a></li>
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<li><a href="../../../index.htm">CUCC Home</a></li>
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</ul>
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</body>
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</html>
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