I'm rehabbing my MILs old road bike. It has an old shimano derailleur that, instead of mounting on a dedicated hole on the drop out, clamps itself under the quick release around the axel.

The problem I'm having is that derailleur doesn't have any knurling on it so that when you torque up the drive train it lets the axel shift in the dropouts and the tire ends up sideways rubbing against the chain-stays. I've got the quick release clamped as tight as I can get it without using a tool to raise and lower it. It seems like the derailleur is providing another slip surface and is keeping the knurling on the inside of the QR nut from grabbing the drop out like it normally would. I'm considering getting out a checkering file and putting some texture on both sides of the derailleur tab, but I figure there must be a non Neanderthal way to accomplish this.