A bridle is a piece of horse tack that fits over a horse's head, used to direct it while riding. According to Carolyn Henderson, author of "Horse Tack Bible," most modern bridles are made from leather or braided rope. You can make a simple rope bridle from a length of nylon rope as an alternative to the common commercially made bridles. Rope bridles make a gentle alternative to a bridle with metal parts, and work in a pinch if your horse's bridle breaks.
Fill a small glass with cold water.
Melt both ends of the nylon rope using a lighter. Hold the rope over the flame until it melts into a rounded nub, and then place the melted nub into the cold water to harden it.
Measure the length around your horse's lower jaw. Carefully place the measuring tape through his mouth where a bit would sit and draw it underneath his jaw. Measure and add four inches; this is the mouth band length.
Measure the length from one side of your horse's mouth, up over her head behind the ears, to the other side of her mouth. Add two inches to this measurement. This is the headstall length.
Measure the mouth band length from one end of the nylon rope. Tie this length in a simple overhand knot to form a loop.
Measure the headstall length beginning from the knot that forms the loop. Tie the rope at the end of the measurement in an overhand knot to the mouth band loop, directly across from the existing knot.
Tie the remaining length of rope to the original knot that secures the mouth band loop to make the bridle's reins, and complete the rope bridle.
Do not ride a horse with a rope bridle unless he has been previously trained with one in a controlled environment. Rope bridles can severely injure a horse's mouth if used roughly; always use a light hand when riding with one.