I have a piece of very straight grain osage board that I am planning on backing with Boo. I have a osage board bow from the same tree backed with hickory that seems to be a shooter that I rounded the belly. My question is at approx. 62" x 1 1/4" wide do I slightly round the belly or keep it flat.
Pipedream, I started rounding the belly slightly on the osage bows I've made and they seem to perform well. The rounded belly seems to help add a little zip to the shot.
My first bows were mostly red oak board bows with flat bellies. The first osage bows I attempted also had flat betties. None of those bows were very impressive when shooting. Many of them failed and had chrysalling on the belly.
I like flat with rounded edges myself. The highest point on your belly will do all the work. If you decide to round them keep that in mind.
I fully radius ALL of my wooden bows' bellys regardless of whether they're selfbows, boo backed, wood backed, sinew backed, made of osage, hickory, elm, ash, cherry, hophornbeam, yew... you name it.
IMO, an unradiused belly ain't done yet :)