Originally Posted by Scissor Queen
When you put your selvedges together do you make sure the fold is straight? If it doesn't hang in a straight U you don't have it folded straight. Make sure your second fold is also straight. Then you have to make sure your ruler is at 90 degrees to the fold.
The last sentence is the most important thing to remember. Your ruler must be at a 90 degree angle to the fold (use the lines on the ruler to align with the fold).