Step 1
Determine which gate post the gate is attached to, then locate the top corner of the free-swinging side of the gate. Measure on a diagonal between the top of the post and the corner of the gate. Add 12 inches to that to determine how much cable you need for the guy wire. Cut your cable to that length, and then cut it in half.
Step 2
Drill a hole through the gate post near the top and insert an eye bolt. Place a washer over the protruding end of the bolt and secure it with a bolt. Tighten the nut until the eyebolt is held securely and the bolt cannot move.
Step 3
Feed one end of the cable through the eye bolt. Bring the end out and around to make a loop so that about 3 inches of the end are next to the main section of cable.
Step 4
Place a cable clamp over both pieces of cable and tighten them securely. This will hold the cable in place through the eyebolt.
Step 5
Put the other end of the first piece of cable through one end of the turnbuckle. Make a loop of the cable and secure it with a cable clamp so that the turnbuckle is now attached to the cable.
Step 6
Drill a hole in the top rail of the gate on the side away from the hinges. Insert an eyebolt through the hole and secure it with a washer and nut. Tighten it securely so that it can’t move. Attach the second section of cable to this eyebolt by looping it through the hole and using a clamp to hold it in place. Connect the other end of the cable to the free end of the turnbuckle. There should be very little slack in the cable at this point.
Step 7
Place a block of wood under the free end of the gate, to lift it off of the ground. The wood should be thick enough to provide adequate clearance for the gate.
Step 8
Tighten the turnbuckle with a wrench until the cable is taught. When the block of wood is removed, the guy wire should hold the gate at the same level, enabling it to swing freely.