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Power Screw Question

  1. May 25, 2009 #1
    I was reading through some examples in my Design text when I came across this one.

    This was their solution:


    I am not sure that I completely follow it. Can someone help shed some light on what's going on here?

    I am assuming that the specimen to be put under tension goes where the "B" dimension is right?
  2. jcsd
  3. May 25, 2009 #2


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    Yes, the tensile specimen goes where the B dimension is. Both screws must have the same hand. My impression is, their explanation is very poorly written. Here is the answer I arrived at before reading their solution. The machine is missing thrust bearings at the top of the screws. Therefore, the machine should not be used for a compression test, because galling of the upper channel web material might occur. Plus, the diagram shows only a small-diameter shank inside the upper channel.
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