4" Square to Round Cork Coaster Template Holder

I originally used my CO2 laser to cut 4" squares for slate coaster engraving. I wanted to use the same template for 4" round cork coasters, but the cork coasters were more like 100mm, making it a loose fit. This would cause the coasters to move around when engraving. This jig inserts into the 4" square and allows the cork coasters to fit snugly, while being easily removed when needed. This was designed to fit the squares my laser cut out, which have a slightly focus bevel along the edges, and the specific cork coasters I buy, which are labeled as 4", but measure 99.5-100mm in diameter. Results may vary.