I have never worked in Osage or Yew. But I know a few thigns from reading and general wood work. Not all Yew is the same. Yew has been a premium bow wood for centuries.
Yew is behind the loss of nearly a whole generation of French nobility (what ever that means). It made deadly bows on a comercial scale. There is a reason it is so expensive.
So rather than blaming the species perhaps look at the piece or the operator
. My guess is that you need to add more steam time and possbily more heat.
Steaming the middle will mean that you are loosing heat as it is drawn out to the ends. That will need to be compensated for by time.
There is probably more mass at the handle then out at the ends. That will need to be compensated for by time.
The design of your steam box may be inefficient. I read some articles about using PVC becasue it's a better insulator than wood ones or metal ones. I'd say try to find some urethane board?
Or try the wet shirt and tin foil method. Personaly I'd want to make sure I got even heat and steam all around and could quickly get it where it needed to be and bending.
I recently watched a video on Nova about rebuilding the pharo's chariot. The long gooseneck section was breaking when they tried to bend it to match the curves in exibited originals. They extending the time in the steam oven to 6 hours (I think) and it worked.
I'd say if you are steaming 45 min.. try 2 hours, get it HOT, use alot of steam.
Don't give up but don't get stupid. Step away from it till you can remain objective and you aren't mad at it.
Just my $.02.
