There's a pricey set of rulers at Quilting Tools for No Math Quilting, Accurate 1/4" Seam Allowance. Non slip quilting ruler with Fabric Guide. Guidelines4Quilting designs and manufactures quilt tools for accurate piecing and cutting. Our Finished Size Quilting system lets you make q that are absolutely wonderful. First, they're uber-accurate because they were designed by an engineer who figured out that 1/8-inch is close but not precise enough for perfect piecing. Second, this same engineer created clear stripes that run down the edges of the rulers and transfer your downward pressure to these edges. Result? Those rulers ab-so-lute-ly do not slip!!!

Here's the good news, now you can buy these edge grippers and put them on your own rulers. They're amazing. I encourage you to order a set of two.

Best of luck!