How to Cut Vinyl Window Grid Inserts to Size

Measure the window sash's opening with a tape measure. If the window uses a beveled opening, measure the window's smaller daylight opening and the larger sash opening. The daylight opening touches the window pane.

Arrange cuts on the vinyl window-grid insert, using a pencil to place measurement marks on the grid's surface. If the window uses a sash with a flat opening, place the measurement marks on the vinyl grid's exterior side. If the window uses a beveled sash, place the sash measurement on the grid's exterior side and the window's daylight opening on the grid's interior side.

Cut through the vinyl window-grid inserts along its sash-opening measurement marks, using a 4-inch angle grinder equipped with a 4-inch fine-tooth wood blade. Hold the center of the blade on the measurement marks. An angle grinder's high-speed rotation combined with the fine-tooth blade leaves smooth, chip-free cuts along the grid's edges.

Cut the beveled edge of the vinyl window-grid insert, using the angle grinder's blade to custom cut the bevel's angle. The bevel's angle depends on the window manufacturer's sash design.

Test fit each vinyl window-grid insert in its respective window. The grid should slip in the window sash's opening without binding. Trim the grid as needed.