Ice screws are used as a benchmark when ice climbing. Ice screws are pipe screws with very sharp polished tips and a coarse thread outside. They are made for reasons of weight occasionally made of titanium, but mostly of steel. Depending on the model is attached to the securing lug a small crank handle, which facilitates the screwing the screw into the ice.
They are inserted with one hand in the ice and the ice blasted displaced is transported through the hollow ice screw to the outside. In the security lock slot, a carabiner to set up a stand or a Expressset be suspended for laying an intermediate backup. When Standplatzbau two ice screws in the ice with a belt loop are connected by a triangle of forces in general. The angle of this triangle of forces should be as small as possible in order to reduce the forces acting on the ice. Optimal is the distribution of power, if the screws are one above the other and 50 inches apart arranged.
Strength tests by Black Diamond, a manufacturer of ice screws, overall strengths of the Eissicherung of up to 40 kN have shown. The German Alpine Association has also investigated the strength of ice screws and fuses in the ice. There the Eissicherung of up to 22 kN were measured in "good ice " strengths. ( The measurement setup could display as the maximum force only 22 kN. ) Expressed old units correspond to 22 kN 2200 kg respectively. 4000 kgf at 40 kN. When trying a number of bolts were torn from the rock and aluminum carabiner failed.
The first ascent of the north-western wall of the Great Wiesbach horn used in the Glockner group Willo Welzenbach and his companion Franz Riegele 1924 first ice picks. Besides the advantage of rapid setting a major drawback of ice picks was the need to have to unlock the beat almost completely to them - once frozen - to capitalize on the ice again. In about 75 years, (1 and 2) developed by the ice picks on the Marwa screws ( 3), ice screws of the 1970s ( 4) and the Rohreishaken ( 5) ice screws from today (6 ), which by itself can unscrew the thread again.