I'd suggest that any instructor who failed a student for "not making a bow shaped bow" ought not to be an instructor. And maybe all those instructors who would disagree that a bow shape isn't as effiecient just haven't been shown a better wayBack to the original question "what's the easiest way to get good tension with the bowdrill"
In my part of Canada it's almost impossible to find an "L" or "j" shaped piece of wood for a bow, it's strange how differently the trees grow in different locations. Some days I've searched for literally hours while out hiking in and not found my ideal bow, when I do find one I cherish it! It doesn't mean I can't use something that's not perfect but if I was begining and having trouble getting things to work I'd start with the easiest idea first.
The thing with the "L" shape is you don't have to start with much tension on the thong at all, a lot of problems come from too much or too little tension as you experienced firelighters know. Too much and the spindle wants to flip out and the thong wears faster and too little the thong slips on the spindle. All of that is eliminated if you can vary the pressure. By the way before someone says "but you can vary the pressure with a regular bow," sure you can but not as easily or as consistently.
Happy firelighting and stay warm!
I was doing some bow drill demos recently, and found an "L" piece which I then corded up. I haven't used it yet, but following your experience with the more adjustable tension I shall try it soon and report back.
