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Kurbeln mit Splintbefestigung: Unterschied zwischen den Versionen

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→‎Splinte ausbauen: Übersetzungsanfang
(puh... schwieriges Thema)
(→‎Splinte ausbauen: Übersetzungsanfang)
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==Splinte ausbauen==
==Splinte ausbauen==
Widerspenstige Kurbelsplinte gehören zu den größten Herausforderungen bei Reparaturproblemen. Der erste Versuch sollte immer der Einsatz einer [[Splintpresse]] sein. [[Park Tool]] hat die wohl beste hergestellt und ist im wesentlichen eine sher schwere "C"-förmige Klemme. Der Hersteller Var (aus Frankreich) hatte auch Splintpressen mit einer Nocke und langen Hebeln im Angebot, die wie bei einem Bolzenschneider aussahen. [[Sheldon Brown]] hat es allerdinsg geschafft, einen solchen zu zerbrechen.


Recalcitrant crank cotters are among the most challenging bicycle repair problems. The first thing to try, if you have one available, is a cotter pin press. Park makes the best one I know of, it is basically a super-heavy-duty "C" clamp. Var also makes a cotter pin press that uses a cam and long handles like those of a bolt cutter. I broke one once :-(>
Die Park Tool und Var Werkzeuge sind inzwischen vom Markt verschwunden und man kann derzeit (2018) bei [http://www.bikesmithdesign.com/CotterPress/ Bikesmith] in den USA eine Splintpresse beziehen.


[Update, September, 2013: Park and Var cotter pin presses have been discontinued but one is available from Bikesmith.]


The hammer and pipe system is best if you don't have a press, or if the press fails. You need a short length of pipe, long enough to go from the underside of the crank to the floor. Wedge it in position so that the non-threaded end of the cotter can fit inside of it. The pipe will transmit the impact of the hammer to the floor, so as not to damage the bearing cups or axle cones. It is best to rest the pipe on a concrete floor or to place a thick, steel pad under the end of the pipe. You could damage a wooden floor, and as the pipe indents the floor, it won't provide as good protection to the bearings.
Die [[Hammer]] und Rohr-Methode ist die beste Variante, wenn man keine Splintpresse besitzt oder diese Methode fehlschlägt. Dazu benötigt man ein kurzes Stück Rohr, das lang genug ist, um von der Unterseite der Kurbel bis zum Boden zu reichen. Man verkeile das Rohr so, dass das Splintende ohne Gewinde in das Rohr ragt. Das Rohr wird die Einschläge des hammers auf den Boden übertragen, so dass die Kugellager oder Achskonen nicht beschädigt werden. Am besten steht das untere Rohrende auf einem Betonboden oder man schiebt ein dickes Stück Metall unter. Ein Holzboden könnte Schaden nehmen, wenn das Rohr durch die Schläge Dellen formt und bietet keinen guten Schutz für die Lager.
 


The more rigid the support, the better your luck is likely to be. One neat trick is to place the head of the cotter inside another cottered crank, used as an anvil as shown in the photo below. (Use a left crank so there won't be a chainwheel or crank spider in the way of your hammer.) The crank in the photo is resting on a steel fencepost which is filled with concrete and set in concrete at its base. The cotter shown, already mushroomed by several failed attempts, let go with one hammer blow when resting on this support.You could also rest the assembly on a bench vise or an actual blacksmith's anvil, if you have one.
The more rigid the support, the better your luck is likely to be. One neat trick is to place the head of the cotter inside another cottered crank, used as an anvil as shown in the photo below. (Use a left crank so there won't be a chainwheel or crank spider in the way of your hammer.) The crank in the photo is resting on a steel fencepost which is filled with concrete and set in concrete at its base. The cotter shown, already mushroomed by several failed attempts, let go with one hammer blow when resting on this support.You could also rest the assembly on a bench vise or an actual blacksmith's anvil, if you have one.
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I prefer a claw hammer to a ball peen. Claw hammers are designed to drive nails without bending them, and that is very similar to what you want to do to a cotter. Most people are scared to hit a bicycle with a hammer, and are afraid they will miss if they swing too hard. They go "tappy-tappy-tap", nothing happens, then they try hitting a bit harder, then harder still, until the end of the cotter is mushroomed over or bends. If you are going to hammer a cotter, pretend that you are going to try to smash the crank right off the axle. Hold the hammer by the end of the handle, and give it everything you've got! It may work, or you may just bend the end of the cotter over. If you bend it, use the claw of the claw hammer to straighten it, then try again. If you repeat this cycle unsuccessfully a few times, the threaded end of the cotter will snap off.
I prefer a claw hammer to a ball peen. Claw hammers are designed to drive nails without bending them, and that is very similar to what you want to do to a cotter. Most people are scared to hit a bicycle with a hammer, and are afraid they will miss if they swing too hard. They go "tappy-tappy-tap", nothing happens, then they try hitting a bit harder, then harder still, until the end of the cotter is mushroomed over or bends. If you are going to hammer a cotter, pretend that you are going to try to smash the crank right off the axle. Hold the hammer by the end of the handle, and give it everything you've got! It may work, or you may just bend the end of the cotter over. If you bend it, use the claw of the claw hammer to straighten it, then try again. If you repeat this cycle unsuccessfully a few times, the threaded end of the cotter will snap off.


==Schwierige Splinte entfernen==
==Schwierige Splinte entfernen==
15.340

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