As to the question on how this is done...there are several ways to put a "set back" in a bow. You can use, lard and heat, dry heat, or steam. Now when you use steam you are putting moisture back in the wood and this could cause checking and cracking so When stem is used you should coat the bow in some kind of sealer so it can cure slowly and loose the moisture without damaging the wood. I seal with bacon grease.
When you use lard and heat you are basically using the lard to lubricate the wood fibers to help protect them from the heating process.
And dry heat has to be done very carefully because you can not get the wood to hot or it will burn or split. So those are some of the methods that are used to achieve these bends. I would never reccomend boiling the wood if it's osage because the boiling although allows for great bends it seems to take something away from the wood.
Always degrease!
I will say that many bowyers prefer steam but to me that is the least favorable.
The bows with the greatest set back are very difficult to make and tiller.
Eric
