Michael,
Additionally when we consider guide or stops with 0 mm gap, one or two rotational movements also gets arrested (see sketch).While doing piping stress analysis there are many assumptions, depending upon criticality of the system we should try to build our theoretical model to simulate actual condition of the system.
For critical system such as compressor, turbine etc. where 0 mm gap is required to achieve nozzle loads, I prefer to use rigid struts. Advantage is that we can achieve near to 0mm gap with almost negligible friction. Rotation of strut needs to be taken into account.
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