Select two sturdy 6-inch diameter logs. Cut both logs down to 4 feet long. These are the sides of the gate.
Cut two 3-inch diameter logs to 3 feet long. These are the top and bottom of the gate.
Cut both ends of each of the top and bottom logs down to 2-inch diameter tenons. Make the tenons 1 inch long. These attach the logs to the sides.
Measure 3 inches from the top of each side log and drill holes. Make the hole 1-inch deep and 1 inch in diameter. Repeat 3 inches from the bottom of each side log. Use a chisel and hammer to widen the holes to 2 inches in diameter. These are the mortise for the tenons.
Drill a 1-inch deep and 1-inch diameter hole every 6 inches along the top log. Repeat on the bottom log.
Cut seven 1-inch diameter logs, each 3 feet long. These are the inside logs for the gate.
Fit one end of each of the inside logs into the mortises in the top log. Enlarge the hole with a chisel if needed.
Fit the opposite end of the inside logs into the holes on the bottom log. Be sure each mortise and tenon joint fits tightly.
Fit the side pieces to the ends of the top and bottom logs. Enlarge the tenons as needed with a chisel. Push all the logs together ensuring all joints fit tight.
Attach one of the gate hinges, 3 inches from the top of the fence, using screws. Attach another hinge 3 inches from the bottom using screws.
Hold the gate in the 4-foot wide opening between the two posts. Attach the hinges to one of the posts, being sure the gate is 6 inches from the ground. This will allow the gate room to swing open and shut. Tie the gate shut with a piece of rope.