Is it set?

[stuckinthemud]

Is it set when a stave seasons and warps into reflex, then as you tiller, the reflex pulls out and the bow goes back to being straight?

[Hamish]

It is set in my book. I always go by what the stave looks like before tillering, compared with what happens after. It might be set, but not necessarily string follow. A stave that was naturally deflexed yet takes barely any set, still looks to anyone that didn't know what the stave originally looked like, is perceived as a bow that has taken string follow.
You are a very experienced bowyer, is this some kind of crazy trick question? If a tree falls in the forest, and it happens to be osage...

[stuckinthemud]

Nope, I never worked with a reflexed stave, except once as a much less experienced bowyer, and now I have head space to consider things I didn’t think about before.  My question goes like this.  If Set is caused by compression damage then is returning a stave to its original shape actually causing compression damage or is the stave just going back to it’s grown shape, ie not receiving damage, just being straightened? This has greater relevance as I never yet deliberately reflexed a stave before tillering, so, does heating in reflex before tillering reduce compression damage during early tillering?

My current idea is that by taking those cells that have been stretched by warping (and compressed on the back) and returning them to nearer their grown shape, you are not causing set but I would welcome other opinions on this.

[Selfbowman]

Ok if the bow blank does not change before heat is applied . Then I would say no to set . I also think when we apply heat to the bow blank and change its shape not all of the changes hold a hundred percent. Some just pulls out. I’ve noticed that  natural reflex in Osage does not change from stave to bow blank unless maybe the stave is not completely dry.so anything after that is set. Just an opinion.

[Hamish]

 How much reflex are we talking about? If its only a couple of inches then there won't be a practical difference.

[willie]

not sure what you call it, but consider that green wood is  flexibile,  and then when it dries the cells get stiffer,  so comparing green wood to dried wood is sorta like apples and oranges.

btw, the shape or reflex of the dried stave was caused by the the outside drying and shrinking faster or sooner than the middle

[superdav95]

I think that changing the reflex from natural shape with heat on the belly will make the belly less susceptible to taking compression set.  There still is some set that occurs but it’s minimized with the hardened cells of the belly wood.  It also makes those cells less likley to absorb moisture too compared to just air dried seasoned wood.  Like has been said here already.  I count set from the pretillered state and backset or deflex at the start of tiller.  I do find that natural reflex holds better and takes less set also.  I also find that with heat treating a ton of reflex or backset there is a limit to what the bow will retain.  Too much reflex or extreme designs on self bows is risky and have greater chance of failing.  Keeping it to 3-4” is the limit for me with self bows with heat treating on white woods.  This can be increased with backings like sinew or bamboo or others backings. 


Cheers