... than free length of spring .It can increase service life.>. scroll spring only use for compression ,except extension ,torsion , or will ... be bending .transforamtion and scrap ,etc.Tolerance limits of scroll spring: Outer Inner free length free length load curl direction ... .5mm±1mm ±10% right Deformed degree and working life of scroll spring Working time 1 Million time 0.5 Million time ...