How to Cut Angles for a Deadman Fence Brace

Stretch the tape measure across the scrap lumber. Mark the length of the deadman post brace. Although length varies according to application, 6 to 8 feet is standard.

Butt the narrow side of a framing square, called the tongue, against the edge of the lumber to position the wide side of the square, called the blade, perpendicularly across the lumber's face. Align the square's blade with the cut mark. Run a pencil along the square's edge to lay out a cut line across the lumber's face.

Lay the lumber on a stable cutting surface such as a pair of sawhorses or workbench. Alternatively, lay the lumber on the base of a bench saw such as a miter or chop saw. If you are using a portable circular saw, extend the lumber's cut line over the edge of the cutting surface.

Rest the nose of the circular saw's base near the edge of the lumber's face and align the saw blade with the cut line. Pull the blade away from the lumber, activate the saw and slice through the lumber along the cut line. Alternatively, position the cut line beneath the bench saw blade.

Lock the bench saw blade in the 90-degree crosscut position position. (Miter saw blades typically rotate and lock in position via a sliding plate and knob located on the front of the saw's base.) Ensure your hands are clear of the blade, then activate the saw and lower the blade through the cut line.

Dig a small trench on either side of the posthole to accommodate the deadman brace lumber. The trench must allow the deadman to butt perpendicularly against the face of the post on the side of the post that experiences pulling force. In other words, position the deadman post on the inside face of the post. Dig the trench deeper than the brace's height, as the brace must rest several inches below ground level. Lay the brace in the trench during post installation.