Adrian,
Yes, I too, had this problem. I think it must have been due to plating the drum, though, the hub and drum did not start life together. It's been a while, so I don' recall exactly the feel of the fit, but I ended up fixing the problem. That last sentencce was going to keep going until I realized that I could not remember exactly how I fixed it. It was either by using a file or a Dremel tool a tiny bit on both sides of each tooth. I do, however, remember my shooting a short bit of video of me doing this. I know, it sounds stupid that I can't remember such a pain-in-the-backside task. I think I probably tried both approaches and the winning method just escapes me. On the other hand, it was just one in a history of such tasks, and, by far, not the worst. I'm curious if anyone else here has done such QD-spline dentistry.
Richard L.