I built this jig about 10 years ago while waiting on a job site for a building inspector. The parts — laminate countertop scrap and an old 2-foot wooden level kicking around the back of my truck — were cheap.

After cutting the countertop roughly to size, I drew a baseline along the bottom edge and marked a pivot point at one end. Then I measured over 24 inches and made a second mark, drew a second line perpendicular to the baseline, and marked this line every 2 inches.

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