Old thread here but maybe someone will catch this.
I've had some issues with localized fretting/chrysals on two of my sugar maple bows. Both were from the same tree harvested in the summer in Vermont. A 10 inch log that yielded 6 staves, so I have 4 left. The first bow I build was a flatbow 66" ntn with a pyramid design, 50# at 28". I shot it for months with no issue. After moving it to a slightly more humid climate and leaving it unstrung for a few weeks, I took it down and strung it. After inspection i noticed a 2 inch patch midlimb (lower limb) had developed a serious chrysal network. There is a tiny dip in the back about an inch above it, and i suspect that was the culprit. It did not take long for the bow to take excessive set there and I've set it aside as a learning tool. the maximum width for this bow was 1 and 7/8" at midlimb.

My second sugar maple bow is 65 inches ntn and 47# at 28". I recurved the last 6 inches and it holds about 1.5 inches of reflex after about 100 shots. I kept the bow fairly wide, 1 and 3/4" inches at midlimb. I was feeling redeemed in the sugar maple camp and the bow was shooting really clean and fast. The other day after stringing it I noticed a localized fret on the lower limb, again. It's smaller than the last patch and the bow has not taken any noticeable set. I have not shot it since but was thinking i would go ahead and put it through the paces and see what happens. Bad idea?
Besides an overstrained cherry bow, I have not experienced this issue with other white woods. I mainly work eastern hop hornbeam and elm, but I've had some great luck with hickory and white oak staves as well.
Both of these maple bows received a decent heat treatment on the belly and showed no obvious signs of tlller imbalance. I've felt some frustration with sugar maple as both these bows did not seem close to be strained to the limit during the build. I'm hoping to use some of the remainder for cores in a horn/sinew bow.
Anyone else seem to run into this with sugar maple? Any suggestions? I'm wondering too what people's experience is with shooting bows after developing minor chrysals, should i assume they will fail dramatically if shot?
I've heard such good things about it and there's plenty around where i live!
Thank you!