Flatten the broom once the corn bristles have been tied to the handle. Do this with a sewing clamp, which is a simple device made from two small boards clamped together with two screws tightened with wing nuts. You can build one by drilling a hole in each end of a 1-by-2 section of board and sliding the wing nuts and bolts through. Slip the clamp over the broom and tighten the nuts until the broom is held tight between them.
Stretch out a length of waxed hemp. Hold the cord at your waist and stretch your arm out to its entire length three times. Fold the cord in half.
Loop the folded cord around the broom bristles then tie a lark knot, also called a slip knot, by slipping the two free ends of the cord through the folded loop. Orient the knot to the side of the broom.
Thread the needle with the top piece of cord. Make one stitch at the side of the broom to secure the cord.
Lay the bottom cord flat beneath the broom corn. Use the needle to stitch all the way across in a lock stitch --- move the needle over a small bundle of bristles, then down through the broom; lock it around the bottom thread then immediately back up. This creates a looped stitch holding the bristles. Continue all the way across. Tie off the last stitch to secure it.
Thread the bottom string into the needle and run the needle straight back through the center of the broom and out the other side. Tie it off and cut the strings flush. Do three rows. Alternate the location of the stitches so the drop of the stitch on each row isn't in the same part of the broom for more strength.