Does zero set mean "overbuilt" ?

[PatM]

I doubt it's anywhere near that  level or at that speed, Steve. The limb would return too slowly to push the arrow if you start talking more than even fractions of a second.

[Badger]

Pat, you atr talking in thousands of a second. The healing process on the limbs starts occuring the very second you let go of the string. If there is no healing to do a bow has no histrias. How fast that bow recovers it original shape is what concerns us, any recovery that takes place after the arrow has left the bow is set regardless of what we see 2 seconds after we unstring it.

[willie]

well i was remembering something I watched when the bow was still on the long string. now you got me thinking .....

you could make a string that you could instantly change from long to short, then you might be able to watch the bow relax as you tiller out further.

[PatM]

I think you have to consider the momentum of the loose. If you break a string on the loose the limbs almost certainly instantly go past the resting unstrung position.

[willie]

patm,

i think we are talking about different things

[PatM]

   Not at all. A broken string represents what happens with a quick unstringing better than anything.

[willie]

i am thinking of how to monitor set while tillering a bow.

[PatM]

 I am going by the thread title and the main portion of the discussion.

[Badger]

Willie, you can easily monitor set while tillering a bow. Find out what your bow is pulling at say 12", evrey time you go past 12" come back and recheck the weight to see if it has changed. Any change in the weight is set regardless if you can see it or not. Of course if you remove wood to adjust tiller you can expect to loose weight so would need to go back and restablish a new benchmark.

[Badger]

  going back to the thread title as Pat suggests, I think a zero set bow probably would be overbuilt but not neccessarily have to be. If the mass of the bow was overiding the  positive effects of low histerias then it would be overbuilt

[George Tsoukalas]

Overbuilding a bow is not necessarily a bad thing.
Read The Bent  Stick by Comstock.
Jawge

[SLIMBOB]

I agree with that Jawge.  Over building a bow would mean either making it longer than is needed for the intended draw length or wider than is needed for the intended draw weight.  One would first have to know what the "ideal" would be for each individual bow stave.  That alone is more of an educated guess than anything else.  Certainly experience gets you in the ballpark on those numbers, and using the mass principal gets you even closer, but I am still making some assumptions after a certain point.  That being the case, and this pertains to my level of experience only as others may have narrowed the field even tighter, the question really is how long and wide should I make THIS particular bow.  An Osage self bow puling 50 lbs at 27 inches, stiff handle...64-66 inches long and 1 3/8 inches wide...some of mine will take very little set at those dimensions, and others will have more noticeable amounts.  I would not classify the former as being "over built", just well built for that piece of wood.  Over built might apply if you instead were making those same Osage bows 2 inches wide or 70 inches long.  They may show very little set but you clearly have more mass than is needed and that mass will have a more negative effect on the cast than the lack of set can make up for.  Just my rambling thoughts on the matter this morning.

[George Tsoukalas]

Slimbob,

That's why making self-bows is an art.

I basically let the stave determine the design.

Let's take osage, since you mentioned that wood. Let's say I want  45-50#. The stave has no knots, relatively thick rings, and good early to late wood...nice and orange.
Then I'll go 1 1/8" wide and 64-64" long ntn. I have a 26" but I like smooth all the way back.

If there are knots, poor early to late wood ratio, or thin rings then I'll go wider...say 1.5 inches.

What if that is too wide for the stave? It will let me know. The stave will begin to get too thin to bend it safely, risking a serious plunk in the head. Been there.

Then I begin to narrow it to bring the tiller home.

Jawge

[RyanY]

When I think about optimizing a bow I look at it in terms of thickness and width. Thickness is what determines the bend radius at any point along the limbs. For optimization this means we want the maximum thickness the wood can bend at without taking set. Once we have the correct bend we can adjust width for our desired draw weight. With maximal thickness for the correct bend and the minimal width for draw weight we get the smallest cross sectional area which means the least amount of mass necessary for the bow. Length comes into play by adjusting thickness where a longer bow can accommodate a larger bend radius and therefore the thickness will be greater before taking set. When making a bow there is a lot of factors in the building process that can effect how it takes set. An optimal method would start with wood wider and thicker than necessary and adjust both width and thickness as we assess for set. If the bow is bending 20" for a 28" draw bow and has taken no set than we can reliably reduce width as the thickness is at a point where it is not stressed. I think for many of us we start at a width that we feel will work for the bow and go from there. I'm sure this is what people like Steve do in his no set tillering. It is an interplay of width and thickness to achieve the lowest cross sectional area and therefore mass.

[George Tsoukalas]

Here is how I minimize set.

First, moisture content is vital. I use a moisture meter throughout right down to the stave's initial stringing. I look for the wood to be at 8-10% except for hickory at 6-8%.

Second, I floor tiller getting the limbs to bend a few inches.

Third, I long string tiller out to 10 inches of string movement (for a 26" draw) looking for target weight or a little more and good limb bending. Don't force it to 10 inches. Easy does it. My aim is to be no more that 15# above target weight.

Needless to say I use a rope and pulley.

Fourth, then I string it at 2-3".

Fifth, let's assume I want 48#.  I never draw more than it takes to expose a problem. As I increase the draw length, I increase the brace height. I  look to get in the high 30's for a draw weight at 20". I look to hit draw weight at 25 inches and that's for the first time. I shoot it in to 26".

Since I've used a scraper-like tool since I string it little sanding is needed. I avoid holding for more than a second when shooting.

Jawge