I finally figured out my spine rolls were crooked because of a $4 plastic cutting mat
I was gluing up my third case binding in a row at my kitchen table in Sacramento and every spine curve came out slightly off no matter how careful I was. Bought a cheap self-healing mat and noticed the old one had a bowed edge I'd been lining everything up against for around 8 months, anyone else had a tool quietly sabotage their measurements?
My buddy went through something like this with a warped T-square he used for two years of trim work. Every cut was a hair off and he kept blaming his saw. Felt pretty dumb when his kid used it as a sword and he saw the bend.