A few things you can check for next time.
(1) Make sure your backing starts out square in the frame. You can roll the backing onto the takeup roll and then back again as extra insurance that it is on straight. I always do this.
(2) I use a misting of spray starch as I roll the backing onto the takeup roller (before adding batting). Learned this trick from watching Sharon Schamber on Youtube.
(3) How did you attach the bungees on the sides? It should be just to the backing.
(4) Make sure your cloth leaders are square on the frame. I discovered my cloth leaders were not rolling evenly; they had gotten catty-wonky, probably from me being too rough with them. I noticed this when I rolled the leader completely onto the roller and both ends were longer than the middle!
(5) Also make sure that your rollers are not bowing. If the rollers bow towards the center of the frame as you quilt, you will have excess fabric on the sides that can crease as you work. This is more likely to be a problem if your frame is all wood and not especially heavy, as wood rollers can bow under stress. Also, how tight did you keep the quilt? You want to have it slightly loose (so you can easily grab a finger that is pushed up from below; too tight could cause rollers to bow a little in the middle from stress.
Last edited by Prism99; 09-14-2014 at 05:39 PM.