Also you must realize that there is some small distance that the load table in a spring can will translate without friction, as the coil spring assumes a shape much like a double offset bend, on a much smaller scale. Sliding will begin once the OD of the coil spring meets the ID of the housing.
For large axial movements of piping on a spring can, a roller chair is a nice accessory, but of course it's useless for lateral movement. (Guides are nice!)
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CraigB