I have my Grandma's quilt frame, which is 4 1x2s sized for a double size quilt - as big as they had 100 years ago, which is about how old these are. I don't know what kind of wood they are, but they are just as straight today as when they were made. At that time cut trees were allowed to dry before being cut into boards. Today "green" trees are cut into boards then kiln dried (rather partially dried) so are often warped before they get to the lumber store. Smaller boards like 1x2s are then stood on end and warp even more. If you want to use 1x2s for any quilt frame I recommend going to the hardwood section and paying the higher price for oak, poplar, etc. They will be less likely to warp. Do not stretch the quilt too tightly and your frame should work very well.