So how does set work?

[Ryan Jacob]

Say I have a bow that pulls 35 pounds and another one that pulls 70:
If they both take 1 inch of set, do they lose the same amount of poundage?

Now If I have two bows that pull 50 pounds but one at 26 inches and another at 30 inches:
If they both take 1 inch of set, do they still lose the same amount of poundage?

[Badger]

 The answer is no because not all set is the same. I like to think of hard set and soft set. When a bow is first unstrung it will have a resting profile. One some bows that will stay almost the same after sitting for a while and on other bows it might come back quite a bit. I have found bows with hard set that don't come back tend to shoot better than bows that will almost retain their shape after sitting. Something else about set that is very difficult to gauge is how much comes back the instant you remove the string, of the amount that comes back right after a shot. A bow might have 3" of set but if measured within the `10 minutes minutes might only show 1"

[TimBo]

So hard set is almost more like a naturally deflexed bow?  (I do know the difference between set and deflex and string follow...at least I hope so!)

[Badger]

So hard set is almost more like a naturally deflexed bow?  (I do know the difference between set and deflex and string follow...at least I hope so!)

  As far as I can tell yes. I spent quite a bit of time trying to figure out how set works and I learned a bit about it but a lot more to learn.

[PatM]

If the bows are designed according to their weight it should be the same percentage of weight.

[RyanY]

I can’t speak much to Badger’s points on set but I’ve always thought of the amount of set being related to the length of the bow limb and radius of the bend. I assumed that two long bows of the same length but different weights are taking the same strain if they take the same amount of set.

I think of set as being a signal for efficiency. No set means it’s overbuilt, a little set means you have a good amount of wood doing the work, more set means it’s under built or was overdressed during building. For average length longbows I like to keep it around 1” or less generally speaking.

[Badger]

I can’t speak much to Badger’s points on set but I’ve always thought of the amount of set being related to the length of the bow limb and radius of the bend. I assumed that two long bows of the same length but different weights are taking the same strain if they take the same amount of set.

I think of set as being a signal for efficiency. No set means it’s overbuilt, a little set means you have a good amount of wood doing the work, more set means it’s under built or was overdressed during building. For average length longbows I like to keep it around 1” or less generally speaking.

   I mostly agree with you, but I find accurate set measurement so difficult to do because of the different things that set is telling us. I think most of the set recovery takes place in the first second we unbrace the bow, the next 5 seconds a bit less and then it keeps slowing down until it recovers as much as it is going to. Some of the set recovers right behind the arrow leaving the bow while it is still braced. The bottom line is just measuring performance and efficiency for a given design. This will tell us more about the set than we can actually measure.

[bradsmith2010]

you mean like shooting through a chrono?

[Badger]

you mean like shooting through a chrono?

 Exactly and even that doesn't mean much unless measured under very careful parameters

[bradsmith2010]

bows are mysterious,,,

[DC]

Some questions that rattle around in my head.
In it's purest/performance affecting form is set any more than just damaged wood?

If a stave warps a bit while drying and then that warp pulls out while tillering, is that set? Is it performance affecting? How can you tell if you have a little set and a little pull out?

Same question about heat treating.

When I put in Perry reflex, I sometimes gain a little reflex. So now the bow is gaining a little/losing a little as the tillering is progressing and there is no way of knowing what is causing it.

I don't think that, on an individual bow basis, you will ever be able to predict what is going to happen. All you can do is figure out some general procedures to follow based on a lot of bows(I'm still trying to do that ) and follow those to the best of your abilities and the Bow Gods will take it from there.

[bradsmith2010]

Yes

[SLIMBOB]

Agree 100%. General guidelines but nothing much more will fool the bow gods.

[Weylin]

I don't think that, on an individual bow basis, you will ever be able to predict what is going to happen. All you can do is figure out some general procedures to follow based on a lot of bows(I'm still trying to do that ) and follow those to the best of your abilities and the Bow Gods will take it from there.

This is what I think it really boils down to. That's not to say there isn't value in the more detailed questioning and analysis that people like Steve do, there absolutely is. But for the rest of us I think following what you said will get us good bows pretty consistently. The smart guys can agonize over the details and help push the boundaries a bit further, and that helps us all in the end, but there are so factors at play in any given piece of wood there's no need for every bowyer to kill themselves trying to quantify every aspect of the bow they're making.

[Badger]

   Weylin I am with you on that. When I started studying set my goal was to find out how much avoidable hysteresis there was in wood. My final conclusion was simply the less set the more efficient a bow was regardless of the profile. I also found out that set by itself doesn't tell us all that much because there are different kinds of set. Bottom line just design the bow the best you can and tiller it the best you can.

   One thing worth noting is that heavier mass bows with relatively simple profiles are outperforming the lower mass bows because of less set. Arvins bows are a good example of this. The bow I got from you is also a good example.