Crowned Back on Hickory and Elm

[hickry]

I've just got my copy of TBB4 and am having a blast!  Just hearing about this concept of "trapping" and have a question.  On high tensile strength/relatively low compressive strength woods (like elm and hickory), would building a bow with a high crowned back/flat belly be doing something similar to trapping it?  Would there be a benefit to having a crowned back on these type woods?  I realize there may be a more precise method to trapping than just chamfering the back... but am just curious if others have any thoughts on this? The information may be in TBB4, or elsewhere on this site, but I haven't found it just by skimming.  Thanks, in advance, for your input!

[Pat B]

I've made a few "pole" bows from hickory and osage. They were high crown and flat belly and shot pretty well. With hickory being high crown I guess it is similar to a trapped back because most of the tension stresses are concentrated down the crown on the back.at

[Springbuck]

Yeah, it's pretty much the same, BUT since it is really rounded, you are rally concentrating the forces there at the highest part of the crown.

  Elm sapling bows have always been easy for me, and I have used trees down as far as 2-3/4" diameter or maybe 3", but not much more...

[hickry]

Thanks for the thoughts!  I guess you would really be concentrating the forces at the highest part of the crown.  I wonder, if the outer early growth ring were relatively thick, if it would be better to flatten it some... without violating the ring?  My first thought is that it may be hard to do w/ good consistency and that you would be violating grain... but not sure about that.

[Pat B]

You will do more harm by messing with the back ring. A good bow can be made with the high crown and a flat belly.