Recently got a Bison semi-machined 1.5-8 chuck blackplate from MSC. I've found that the threaded bore and spindle register it comes with is _larger_ than that of my lathe. Am I missing something or is this a defect? I was under the impression that semi-machined BPs were supposed to be slightly undersized so they could be finished to match the machine. This one's so loose it wobbles around quite a bit--larger than 1.5" by a bit.