broke a bow...why?

[mitchman]

ya in my thought it should not take that long to actualy shape and roughly tiller a board bow. i mean dont take it the wrong way it took me 6 hours to do the one im talking about. it wasnt quite as fast as some of you might think. but i started my other bow the other day and i learned from this post a ton. thanks you guys. i took an hour to draw it out and plan it and everything. then i shaped it with my band saw. i use a hand planner to tiller it. it seems to work really well, seeing as you cant take of too much in one stroke like you can with a drawknife. well im out to tiller it down some more and do what you guys suggested. now im so scared of i  braking i will take time and make sure i dont brake it.

thanks again,
   mitch.

[Brokestick]

My second attempt snapped when I suddenly pulled it to a point I had earlier tillered it to without warming it up first.  On further inspection, I found a runout I hadn't noticed before.