It's not the cutting-I did a Moda jelly roll quilt & the bowing drove me crazy & I swore Moda had cut the strips off grain but that wasn't the problem---When sewing long strips together alternate the end you sew at--always starting at one end stretches the fabric a tiny bit but it bows on long strips. alternating which end to start sewing corrects for this and I haven't had a problem since-sorry Moda!!