Originally Posted by NedSVS

I've succesfully straaightened two sets of discs now; both bent due to crash damage. My experience has been that the carrier gets bent and the rotor itself is still a flat disc, but I suppose there are exceptions. I work with the disc bolted to a spare wheel and using an engineers DTI (dial test indicator), placing the wheel on a spindle in V blocks. I "clock" the runout on the inner edge of the rotot and bend the rotor straight by hitting it with a hammer and piece of soft wood (to stop damage). Final tweaking i do with an adjustable spanner adjusted to fit the thickness of the disc and the use this as a lever. Sounds crude, but it does work! The downside - it takes lots of time and patience. I have succesfully trued discs to about 0.1mm runout working like this.