My chuck is a Apprentace 4 way. Mounted on a 3MT arbor. The arbor is way too heavy duty to be bent......I think. I tore the chuck apart a couple weeks ago to clean it but did not help. I did however notice that the teeth were a bit dinged up so makes me wonder if this is all chuck related. I measured the insdie of the arbor and it had very little bounce. Once I mount the chuck and put in a block of wood the wood bounces all over the place. I tried shimming the chuck with paper a couple weeks ago and it did not help.