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I never gave these descenders names. I can number them in chronological order, so I figure I can call them Figure __ descenders, filling in the blank with the number.
I designed all of these descenders in the early 1970s, but until I bought my milling machine, I had no practical way to make models to test. Even then, I delayed until my sister and I found a large sheet of 6061-T6 aluminum scrap in a dumpster where she worked. It was buried under a ton of furniture (literally), but she talked the maintenance men into digging it out for her. After that, I was ready to make chips and make descenders.
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Warning: Do not try making descenders at home. You will die. |
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I made my Figure 1 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 1 is 173 mm. tall, 62 mm. wide, 13 mm. thick, and weighs 167 g.
My first design received its inspiration from the Peck Hook that I saw illustrated in Alan Blackshaw’s 1968 book, Mountaineering, from Hill Walking to Alpine Climbing. The descender is a simple wrap device, but the long shaft allows the wraps to spread out more than they do in a simple carabiner wrap rappel. Unfortunately, the helical wraps cause the user to spin rapidly, just like they do when using a Patten’s Hook (which I didn't learn about until 1972).
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I made my Figure 2 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 2 is 175 mm. tall, 91 mm. wide, 13 mm. thick, and weighs 325 g.
I did not like the spin created by my first idea, so I thought that I could reduce the spin by tilting the shaft. A horizontal shaft would eliminate the spin but cause the rope to bend too sharply, so I decided to compromise and place the shaft at an angle. In the process, I enlarged the hook at the top for security, and added a lower hook for tie-offs. This was an improvement, but there was still more spin than I liked.
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I made my Figure 3 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 3 is 175 mm. tall, 90 mm. wide, 13 mm. thick, and weighs 320 g.
My third descender returned to a vertical shaft, but I kept the large hooks introduced in the second design. If I couldn't eliminate the spin, maybe I could counter it by wrapping the rope in one direction at the top and another at the bottom. The central bar serves as a direction reverser, but I always worried about the rope slipping off the bar.
[ Top | Fig. 1 | Fig. 2 | Fig. 3 | Fig. 5 | Fig. 6 | Fig. 7 | Fig. 9 | Fig. 0 | Return to Plate Descenders ]
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I made my Figure 4 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 4 is 175 mm. tall, 121 mm. wide, 13 mm. thick, and weighs 239 g.
My fourth descender addressed the security issues present in the third design. In this descender, the user pushes a bight through the hole and around the shaft. The horizontal extension on the right helps increase the average bend radius around the lower shaft.
[ Top | Fig. 1 | Fig. 2 | Fig. 3 | Fig. 4 | Fig. 6 | Fig. 7 | Fig. 9 | Fig. 0 | Return to Plate Descenders ]
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I made my Figure 5 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 5 is 173 mm. tall, 90 mm. wide, 13 mm. thick, and weighs 342 g.
My fifth design works more like a brake bar rig, but it does so with no moving parts. Like most single brake bar devices, the friction is low and the rappel fast, and once more, I don't trust the rope to stay where it should.
[ Top | Fig. 1 | Fig. 2 | Fig. 3 | Fig. 4 | Fig. 5 | Fig. 7 | Fig. 9 | Fig. 0 | Return to Plate Descenders ]
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I made my Figure 6 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 6 is 173 mm. tall, 88 mm. wide, 13 mm. thick, and weighs 339 g.
My sixth try returned to the idea two designs earlier of passing a bight though a hole, but rather than passing it around the attachment post prior to clipping in, I added a hook at the top left. The user clips into the large hole, then pulls a bight through the same hole and loops it over the hook. The Longhorn uses a similar idea.
[ Top | Fig. 1 | Fig. 2 | Fig. 3 | Fig. 4 | Fig. 5 | Fig. 6 | Fig. 9 | Fig. 0 | Return to Plate Descenders ]
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I made my Figure 7 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 7 is 173 mm. tall, 102 mm. wide, 13 mm. thick, and weighs 330 g.
My seventh resembled the second, except I added a cross bar to spread the coils, and eliminated the lower tie-off hook. It still spins.
My eighth design was another attempt to pull a bight through a hole, but the resulting design was so obviously absurd that no one would ever consider using it. It is so bad that I refuse to show it here.
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I made my Figure 9 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 9 is 181 mm. tall, 90 mm. wide, 13 mm. thick, and weighs 294 g.
My ninth idea was much like the fourth, except I enlarged the hole and eliminated the horizontal extension on the right-hand side. It work on flexible rope but tends to be rough on stiff-lay braided ropes.
[ Top | Fig. 1 | Fig. 2 | Fig. 3 | Fig. 4 | Fig. 5 | Fig. 6 | Fig. 7 | Fig. 9 | Return to Plate Descenders ]
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| Take a Figure 1 | Add a Figure 0 | Get a Figure 10 |
I made my Figure 0 in 2007 by milling a piece of ½" (12.7 mm.) 6061-T6 aluminum alloy plate. The resulting Figure 0 is 173 mm. tall, 82 mm. wide, 13 mm. thick, and weighs 323 g.
My tenth idea uses two pieces. The first was salvaged from my first design, and the second was a ring. By lying the first across the ring, you have another brake bar rig. Clip into the ring.
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Do not try to use the "0" piece without the "1" or you will find yourself rappelling on nothing! | |
These are not all of my early designs. I have 26 more to make when I find the time.
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