How to Square a Panel

Set the odd-sized piece of panel on a set of saw horses with enough room so you will be able to move around all four edges with ease.

Place the framing square on all four corners to see if you can find one with a 90-degree angle. If you find a corner with a right angle, the task of cutting a square piece will be much easier, and you can go straight to step 6. Otherwise, proceed to Step 3.

Pick the longest edge and measure in one inch from the edge. Do this at two places along the outside edge and make a mark. Each measurement should be made at opposite ends of the longest side.

Chalk a line between the two marks. You will probably need someone to help you hold one end while you snap the line and make the chalk mark on the panel. Then cut along the outside edge of the chalk line with a circular saw or utility knife. Wallboard and thinner paneling can be cut with a utility knife, while everything else will require the use of a circular saw. It is best to use a straight edge to guide you when making the cut.

Lay the short end of the framing square on top of and flush with the freshly cut edge. Next, trace a perpendicular line on the outside edge of the framing square. Do this near one of the corners. Then extend the line to the outside edge of the panel. In essence, you will have a large right angle inscribed on the face of your material.

Cut along the outside edge of the mark until you reach the far end of the panel. Now you should have a four-sided piece of panel with one square corner.

Measure across the length of the panel and make a mark. If you don't know the desired length, make the mark as close to the far end as possible.

Take the framing square and delineate a 90-degree angle at the mark. Extend the line to the far side of the panel.

Cut the panel. This will give you two square corners and three square edges.

Measure the width along the two shorter edges, make a mark and connect the two points with a pencil and a straight edge or chalk line.

Cut the fourth side to make your panel, which now should have four square corners.