This screw was an 8-32 screw that served as a stop for a mechanical jackscrew, and without it, the jackscrew could disassemble and in fact, did while under load. Throughout the investigation, it was discovered that the screw failed in fatigue. Given the occasional marine atmosphere, it was decided that a protective zinc plating would provide some protection, in addition to specifying a cold-formed screw. Upon further investigation of the screw condition, wear on the outer rim of the screw showed significant bending load from stopping the threaded collar that mates with the jack screw.
After interviewing some of the operators, it was discovered that they would tighten the lifting collar into the screw forcibly because operational needs required attention on the lifting task of the jack which was more critical. Simple operational changes such as not forcing the collar into the screw seemed obvious, but a simpler design solution enabled the operators to not change their lifting procedure for the simple price of a replaceable, backfittable protective collar made from PVC piping.
BMC looks for opportunities to apply processing and metallurgical improvements, but occasionally, simple, low-tech solutions allow for easier and more cost- and crew-effective measures. BMC is sensitive to your needs and seeks out efficient and reliable solutions.
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