I messed up this strange piece

[Jodocus]

Bad bowyer's luck this week. First, a very nice hazel bow fretted while shooting in. It was probably just 10 pounds too heavy. I had planned 40@26, and when it was 40@22 and the tiller looked good and I scraped and scraped but it did not come further back, I just slowly pulled it to 26. It looked good,weighed 55 and then fretted when shooting in.
 

Then I had this nice BL strave I wanted to make into a bow for my brother. He had wanted 70# at 32" draw, and I was quite nervous about it, since I have not built in these dimensions yet. I know he'd shoot it regularly and he is a much better archer than me. So I wanted this to be a good bow. I made it pyramidal, 73" long and almost 3" at the fades.
When I had it roughed out, The upper limb bended some, but not the lower. I kept thinning the lower, floor tillering, and even though it was already noticeably thinner than the upper, the lower limb remained stiff. Worse still, the upper, fatter but softer limb took set immediately even from sensible floor tillering. I had it on the tiller on a low brace yesterday, pulled to no more than 40 pounds. 
The limbs are now at similar strenght, the lower still a tad stiffer. The upper has taken so much set despite being much fatter. The mass-center of the bow is in the upper fade!

I'll have to tell my brother he has to be patient...

[blackhawk]

If your getting set from floor tillering, then more than likely your wood is too high in moisture content still

[Zion]

Similar things have happened to me, where one limb is so much stiffer than the other, while being thinner. The best thing that i've found to do is not take too much wood of the lower stiffer limb, even if it suggests to do this. Strange things can happen when wood is wet, and a good sign of this is the set from floor tillering. Let it sit a few more days and then start bending it again. Also if the weirdness persists obviously you could heat treat the weaker limb.

[Pat B]

Are you exercising your limbs after each wood removal? That really helps to register the wood removal so you don't go overboard with it. Are you using a tiller tree while you build your bow? The tiller tree allows you to view the overall bow from a distance while checking to see if your limbs are bending evenly and together. Getting this part of the process out of the way early in the building will help assure you reach your draw weight goal rather than just guessing.
  Your wood needs to be at an optimal moisture content(MC) or the limbs will take set as you stress them if it is still too wet or it will blow if it is too dry. Black locust should be at about 9% to 11% like most other woods(hickory likes 6%).
 Another observation I have is you have also shaped the handle and finished the tips before tillering the bow. Neither of these areas need to be worked until the bow is near finished. If for some reason the bow fails you have not put out unnecessary work. Also, by leaving the handle area and tips wide you can make adjustments to the string allignment after you get to the low brace stage.

[Jodocus]

blackhawk, Pat B, Zion, thanks for your comments. This really puzzled me. I exercised the straighter limb plenty, had it on the tiller, weighed it until i was sure the weight followed the weather but not more. Should I take wood inside before building to get to a good moisture content? The both limbs just seemed to be of different wood. Can a stave be dry in one half and moist in the other? maybe the sealing was better on one end?

However, I'm gonna set this aside and start over. I was hoping that if the lower limb took some set too, I'd just bend some reflex into the handle, but it doesn't.

[crooketarrow]

  Like PAT said you don't have to but From day 1 I always add my handle before tillering. This way for looking a a bow THE WAY IT WILL BE. Some times WHILE TILLERING I'll tiller the bow to line up tips with the handle. This is better than of heat beening.