I had a salesman at a newer LBS trying to sell me a dishing tool. I have never used one and never needed to. My truing stand self centers on the hub bearing locknuts, not on the flanges, so when I build a rear wheel I just adjust and true the rim to be in the center of the truing stand. I have never had a problem with this. Now this salesman tells me that I am doing it wrong without a dishing tool. I don't even know how to use a dishing tool so I don't know if he is correct or not. Is my current method OK or do I really need a dishing tool to get the rear wheels correctly dished? As I said, I have never had a problem with the dish of a wheel when I build one, as far as I know.