I don't have the Q24, nor have I used the cup on my BSR with the 820. However, going back to my Janome 6600 days, there was a spring on the foot to tighten/loosen according to the thickness of the quilt sandwich to get it to glide. So? is there a spring?
Have you phoned your dealer?? ... should be something they could answer simple enough on the phone.
Otherwise, maybe try some Googles???
