Staves with concave backs

[RyanY]

I’m curious what people’s approach is to staves with concave backs. Flat belly vs rounded belly? Decrown the high edges? The stave I’m working on currently has a particularly sharp dip in a couple parts of the limb. Not too uncommon for some woods.

[SLIMBOB]

I have rounded the belly with some success. Don’t much care for them like that though.

[Weylin]

I get valleys in my osage staves sometimes. I stick with the principle of the belly always following the back. So if there's a valley on the back there's a hump on the belly. I had one osage recurve with really thin rings and some valleys where the back would get these little micro-cracks in the valleys when the bow was getting drawn. I had to scrap that bow. Otherwise it hasn't been an issue other than being a pain to tiller.

[Rākau]

I remember simson either posted a bow or has one on his website with a very concave back, I can't remember what he did with the belly though

[bushboy]

Like weylin.....concave back/convex belly.....just even thickness.

[George Tsoukalas]

Like Weylin said, let the back follow the belly.  I am not a fan of a rounded belly. Jawge

[PEARL DRUMS]

I just roll with it. I will give those high, outside edges on the back a very good rounding so they dont pop on me. The bow I refer to as my "baby" is 7 years old and has been shot thousands and thousands of times. It has a long, low spot in the upper limb just above the fade end.

[bradsmith2010]

I would just try to keep the taper even ,,best I can,,if the tiller is good you are naturally compensating for the dip,,,right

[Pappy]

I round the belly in the concave areas, trying to keep the limb thickness the same across it. Like Pearl said it puts a real strain on the outside rails I call them if you make the belly flat. Had a few pop early on but no problems since I started rounding them in those areas.
 Pappy

[RyanY]

My main concern with a rounded belly would be the force trying to flatten it out. That being said, hollow limb bows seem to deal with that stress just fine. Thanks for the wisdom, all!

[Marc St Louis]

Don't like them.  Made a BL static recurve some 15 years ago that had a slight concave back in one area.  It was a great shooter.  Then a few months after making the bow I let a friend try it out and as he pulled it to full draw it pulled a giant splinter right at the concave area 

[DC]

I have a concave Osage stave(my only Osage) that you could use for a water trough. It's the reason I was asking about boo backed Osage a while back. I may just do that.

[Weylin]

My main concern with a rounded belly would be the force trying to flatten it out. That being said, hollow limb bows seem to deal with that stress just fine. Thanks for the wisdom, all!

Well, I think that the stress gets applied differently on a concave back vs a concave belly. In my mind a concave back would have more force trying to flatten in out than a concave surface under compression. I don't have any hard science to back that up, it's just what my logic is telling me.

[Bubbabowyer]

I've done like pd said and just rounded the edges. My fastest bow had a groove 1/3 up both limbs through the handle. I've since searched desperately for another tree with that particular characteristic. Probably find bigfoot first.
 

[Marc St Louis]

My main concern with a rounded belly would be the force trying to flatten it out. That being said, hollow limb bows seem to deal with that stress just fine. Thanks for the wisdom, all!

Well, I think that the stress gets applied differently on a concave back vs a concave belly. In my mind a concave back would have more force trying to flatten in out than a concave surface under compression. I don't have any hard science to back that up, it's just what my logic is telling me.

I don't think it makes any difference.  I heat-treated a very wide, relatively thin limbed HHB bow many years ago.  The process made the belly go concave.  On first stringing one limb split from fade to nearly the tip of the bow