Machinery Dynamics
Cold it runs beautifully. An hour into the shift the cylinder is thirty degrees hotter than the cam ring and the needles seize.
— mm
Clearance left at running temperature; negative means interference
A negative remaining clearance is not a small problem: it means interference, and the machine will bind or gall rather than merely run tight. Free unrestrained expansion of two concentric rings is assumed, so nothing here accounts for the thermal gradient through the cylinder wall, which distorts it out of round and can jam locally while the average fit still looks fine. Both temperatures must be measured on the metal at running speed rather than inferred from the air around it. The needles and sinkers have their own temperature and expansion and are outside this calculation.
Knitting Cylinder Thermal Expansion vs Needle Jamming — free, with the formula and a worked example, at Textile School.