I was hoping to avoid this, but if I haven't made any typographical errors :
For a solid shaft :
Change in outer radius - in
delR = den/4*omega^2/386.4*R^3/E*(1-nu)
where den = density lb/in^3
omega = angular velocity rad/sec
R = outer radius in
E = Youngs modulus lb/in^2
nu = Poisson's ratio