I have three Bernina machines... the 153 QE is the oldest and I've used the bobbin winder on it many many times over the years. I also have a 440QEE and a 530 which I use the bobbin winders on and I have never had a problem with any of them. I have friends who have other types of machines and they don't have any problems either so I don't know why anyone would say something like this.