Others have remarked that their bowdrill set is not really bushcraft since their bowstrings are not handmade. Here is a tip for making your own. You may have read my previous thread Ivan's Bowdrill Challenge in which I made cordage from nettle fiber. There are a number of other materials you can either collect yourself or buy from craft or hardware shops to practice with. Raffia (or Raphia) makes surprisingly strong cordage and is cheap and easy to come by in my area. Craft shops sell it for making the classical grass skirts. This fiber is very slick, so wrap your spindle the Egyptian way to prevent slipping. Anyone else have another favorite fiber?