Outlast 2 stretcher2/16/2024 ![]() ![]() At 60 hours we had to stop the test because the box frame was breaking up in other places where the design is the same as on the 14 year old Model C that we have never seen fail. We installed the reinforcement on a box frame that had developed 2cm cracks and had it go 60 hours with the 600lb fatigue test without any further cracking. After a number of dead ends, we designed a kit that exceeds the criteria. And for the units already shipped, we needed a reinforcement kit could be easily installed by the customer. Ideally, the solution needed to be applicable to both new production indoor rowers as well as indoor rowers that were already shipped. Once we were able to duplicate a fatigue crack, we then tested possible solutions. Fatigue is a fairly random process so each part will be different. With this test we started seeing a fatigue crack somewhere between one and four hours. The test consists of a rapidly alternating load of 600 lbs (275kg) on the rail near the foot stretcher. In order to get results quickly we had to both speed up the cycle rate and use a very heavy load. When we first became aware of a failure, we realized we had to devise a better test that could duplicate this fatigue crack we were seeing in a relatively short time. In hindsight this testing was not quite enough since at least in certain loading situations the frame has not been strong enough. Our pre-production testing of this part showed that we had adequate strength to avoid a fatigue problem. This notch was necessary to prevent the metal from tearing when the box frame was being bent into shape. The few cases of fatigue cracks that we are aware of to date have started at the small notch in the box frame at the end of the bend under the foot stretcher.
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