When sewing blocks for a quilt, one of the most important steps is “squaring up”– that is, making sure all blocks are of uniform size and shape and are perfectly square. Squaring up a block is pretty straightforward, but recently when I was squaring up a bunch of blocks for a quilt, I started using this trick to make things run a little more smoothly and quickly.
First, I take 2 pieces of masking tape and I align them on my cutting mat based on the size of the blocks I am trimming. In this case, I was trimming blocks to be 8.5 inches square, so I made sure the inner edge of the pieces of tape were 8.5 inches apart.
Next, I laid my square between the pieces of tape. I just eyeball it to make sure the middle is centered, but you could mark this off with tape, too.
I position my ruler along the inner edge of the tape, and I trim the block. Note– I also make sure the ruler is lined up with the grid lines on the mat above and below the tape to ensure that the cut is perfectly straight. But, having the tape as a guide makes it much faster to line the blocks up and trim evenly from both sides.
After trimming 2 sides, turn the block to trim the remaining sides. Make sure that the trimmed sides line up perpendicular to the taped lines. I usually pick a horizontal line on the mat and make sure my edge is flush with it before trimming.
And there you have it! Perfectly square blocks, all trimmed quickly with the “cheat” lines taped onto the mat.