Okay, I will give a quick run down of what Im trying to do here. What I want to do is build a tesla turbine from old hard drive disks. Being that they're already rated for high RPM, it seems like a viable option. Now these disks are probably going to be aluminum and Im probably going to buy steel shaft for them to attach to. I know that metals like most anything else expand when heated and contract when cooled. My question is if I were to heat the aluminum disks to a few hundred degrees, and cool the shaft to say -100 degrees (Fahrenheit) ensuring the disks just BARELY side onto the shaft. When the shaft warms up and the disks cool down will the disks contract enough, and the shaft expand enough to hold itself rigidly in place without any glues? Any help or guidance on this would be a MASSIVE help.