Agree 100% with winding the bobbin slowly -- first time I used it both top and bottom was on a very basic Brother machine, and no problem. Then used the bobbin winder on my Viking Sapphire -- had it about half full -- and couldn't get the bobbin off the winder -- it was so tight on there it had to unthreaded, by hand, to release the tension enough to free the bobbin from the post! Sometimes, I use the monopoly on the top, and a regular thread on the bottom which coordinates with the backing. Never have a problem with the top thread pulling up the bottom, so this also works for me.