Chaps, pronounced "shaps" were originally used by South and Central American horsemen, who called them chaparajos. Made from thick cowhide, they were worn over pants to protect legs from thorny underbrush and later barbed wire fences. Today they are part of the recognized clothing for rodeo and show riders, and have been adopted by bikers. They are basically leggings, open at the rear and crotch, that are made of thick material and are pulled over denim or other jeans and have loops to hook into the wearer's belt. They can be worn by men or women.
Make a pattern using newspaper or a large sheet of brown wrapping paper. Take a pair of jeans that fit the person who will be wearing the chaps and lay them out on a flat surface. Use a marker to draw around them on the paper, then set the jeans aside.
Draw a border of two inches around the outline you have drawn, and three inches at the top of the waistline. Fold the outline in half down the center so it is folded in half at the waist and one leg is on top of the other. Cut along the outline you have drawn, then down the fold line to make two pattern pieces. One will be for the front and the other for the back.
Draw a semi-circle from waist to crotch on each pattern piece, leaving about three inches at the outer leg side of each pattern. Fold your fabric in half and pin the pattern pieces onto your fabric. The edges that you folded and cut must line up with the fold in the fabric.
Cut around each pattern piece, then cut out the semi-circles. You should end up with a front and back piece with crotch and pants cut out, and a strip at each side to attach to the belt loops.
Finish the edges around the semi-circles by folding over like a hem and zig-zagging or use a straight stitch. If makes it easier if you hand tack it first, easing the fabric around the circle. Join the inner legs of the front to the back.
Sew the legs together at the outer edges. Fold over the tops of the side panels to make a loop wide enough to fit over a belt. Hem the bottom of the legs and attach any trim or fringing to the bottoms or sides if desired. Pull the chaps on over your jeans and hook the loops through your belt. Ride 'em, cowgirl!!