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5.4 KiB
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html>
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<meta http-equiv="Content-Type" content="text/html; charset=utf8" />
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<title>CUCC Expo Rigging Handbook: Placing bolts</title>
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<link rel="stylesheet" type="text/css" href="../../css/main2.css" />
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</head>
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<body>
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<h2 id="tophead"> CUCC Expo Rigging Handbook</h2>
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<h1>Bolt belays - Hand-drilling and placing spits</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; bollards have almost no
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footprint at all, rings and bends somewhat more, and twists a great deal.
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Remember, of course, that the next person who rigs the pitch may well use a
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different type of hanger from the one you happen to have handy.
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<p>
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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>Hand spits</h2>
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<div class="onleft" style="clear: left"> <a
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href="../../1623/161/l/boltin.htm"><img alt="(36k image)"
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src="../../1623/161/t/boltin.jpg" width="113" height="152" /></a></br><span
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class="caption">Bolting by Hand</br>(click to enlarge)</span> </div>
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<p>Old-style hand-drilled spits are self-drilling; the spit sleeve functions
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both as a drill bit and as an anchor. Screw it firmly onto the driver and tap
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it gently against the surface of the rock, turning it around slightly between
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each tap and removing it to blow dust away every half dozen blows or so. (You
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should also tap the spit itself gently to free dust compacted into it). Once
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the hole is established you can begin to hit a bit harder, but don't overdo it;
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the idea is to powder the rock at the point of the spit without setting up
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cracks through the rest of the rock which will weaken it.</p>
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<p>Watch out for the spit <i>cratering</i>; this is when flakes of rock crack
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away around the rim of the hole. A severely cratered spit is greatly weakened
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as the end of the sleeve is not supported by the rock. With some types of
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hanger (bollards and Clowns) it is possible to drive the spit in a bit further
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into the bottom of the crater, particularly if the rope is thin, but this
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renders it almost impossible to use other types of hanger with that spit.</p>
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<p>There is normally a line around the driver stem around 3mm above the thread;
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keep drilling until this point is reached. (This typically takes around 15-20
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minutes of drilling). Now grab yourself a cone, put it in the end of the spit,
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and hammer it back into the hole. You can normally detect when it is fully set
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by a change in the tone of the sound when you hit it; it should rise gradually
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to a high ring. If the hole is the right depth this will coincide with the spit
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being flush with the surface. Now you can remove the driver and screw in a
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hanger, and Bob's your uncle.</p>
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<h3>Peter and Phil's photo guide to placing a spit</h3>
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<img src="hand_bolting_guide/img_2989.jpg" /><p>Decide where you want your bolt to go.</p>
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<img src="hand_bolting_guide/img_2990.jpg" /><p>Before you start drilling, "dress" the rock; that is, hammer away the flaky top surface of the rock and flatten out a small area around where your spit is to go.</p>
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<img src="hand_bolting_guide/img_2991.jpg" /><p>Hold the spit driver perpendicular to the rock and start hitting it, gently at first, while rotating it clockwise in between taps.</p>
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<img src="hand_bolting_guide/img_2993.jpg" /><p>Make sure the driver is perpendicular to the rock surface.</p>
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<img src="hand_bolting_guide/img_2995.jpg" /><p>After every few taps, blow the dust out of the hole.</p>
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<img src="hand_bolting_guide/img_3001.jpg" /><p>It also helps to give the driver a tap to remove dust caked up on the end.</p>
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<img src="hand_bolting_guide/img_3002.jpg" /><p>When the hole is as deep as the line around the driver shaft (about 3mm beyond the rim of the spit itself), the spit can be set. Take a cone, and fit it into the end of the driver,</p>
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<img src="hand_bolting_guide/img_3003.jpg" /><p>like so.</p>
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<img src="hand_bolting_guide/img_3005.jpg" /><p>Now hammer it in (without turning it, which would rapidly become impossible) until the spit is flush with the surface.</p>
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<img src="hand_bolting_guide/img_3006.jpg" /><p>Finally, squirt a bit of grease into the spit to keep it from corroding. Notice that this spit is rather deep in, and would probably be rather hard to use for a rigging bolt; more dressing would be needed as well. This bolt was actually for the tag on cave 2005-07, and tag bolts clearly needn't be all that strong.</p>
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<img src="hand_bolting_guide/img_3007.jpg" /><p>Finished spit.</p>
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