Jawge is mostly right so far as my experiences go. Most of my bows are Osage so there you go. But when I started most everybody, 'round here anyway was using Osage almost exclusively. The "FF will cause your bows to break" was in an era before all these bows were being made from white woods. Again, Jawges point is a good one in that FF strings may cut into softer woods unless overlays are used or you fatten the loops. I do one or both so never a problem. I believe it is one of those things that got said by a well meaning expert, was repeated as gospel for decades. As Weylin said, so many people using it now without much ill effect.
