Julian, I have made a number of Hard/Rock/Sugar Maple self-bows. None of which have broken. Trap the back, or at least round the edges. Heat treat after floor tiller. If you build it the same design as your previous effort, you should have a good bow, If you choose your board wisely. I have not seen any chrysals in any of my maple bows. Mind, they are 66" plus. Diffuse porous woods can handle a little violation. If you go with flat sawn, make sure the cathedrals are not close together. Rift and quarter sawn, look for nice straight lines. If you get a board say 145mm wide with cathedral middle and rift either side you will get three bows out of it. Rock Maple was my favourite til i used it all up. Now my supplier has plenty of "birds-eye" maple, but nothing with straight grain. Oh well, find something else. I have a white oak bow on the bench at the moment. Probably shoot it in next week. A well rated and tough bow wood.....