Pyramid

[DC]

 From a performance/design point of view is there any difference between bows that have a different taper rate? Like if one bow was 2" wide at the fades tapering to 1/2" at the tips and another was was 1 1/2" wide at the fades tapering to 1/2" at the tips. Same length limbs, same DW.

[Deerhunter21]

just pointing out the obvious but it would be thinner and thicker with the 1 1/2 to get the same poundage and that (at some point) could be better or worse. the limbs would be lighter than the 2" and that might make it faster.

[PatM]

There would be an optimum width relative to material and draw weight so yes.

 For your two examples one would be closer to it's optimum even  if neither are actually close to optimum.

[DC]

just pointing out the obvious but it would be thinner and thicker with the 1 1/2 to get the same poundage and that (at some point) could be better or worse. the limbs would be lighter than the 2" and that might make it faster.

thinner and thicker??? Could you clear that up a bit?

[DC]

There would be an optimum width relative to material and draw weight so yes.

 For your two examples one would be closer to it's optimum even  if neither are actually close to optimum.

Like narrower for Yew and Osage and wider for Red Oak?

[Selfbowman]

DC I have found that the wider pyramid design has helped with set from fade to mid limb. Seems the wider limb spreads the load more even. Yes it makes for more mass but being on the inner limbs the affect on cast is minimal. The fact that the bow does not take as much set makes for a positive in cast.
Arvin

[Del the cat]

For a true pyramid design of constant thickness, the taper makes no difference to the tiller shape... just the draw weight.
Visual proof here!
https://bowyersdiary.blogspot.com/2014/12/pyramid-taper-test.html
Del

[bownarra]

Well done Del good on ya!
I always say do the test yourself and then you actually know...….not just think you know
Another very interesting test is to make test bows and then cut them in half along the neutral plane. You may be surprise at what has happened to the belly compared to the back.

[Selfbowman]

Bow design can change this can it not? Put 21/2” reflex in the ends and it changes the thickness on a pyramid. Yes I agree on same thickness and perfect deminishing mass no matter what the width will have the same arch. I have not bothered to proof this but have thought this for a long time .i think that string angle will also be affected by the induced reflex. Correct me if I am wrong. Arvin

[SLIMBOB]

Arvin my thinking is the same as yours.  In an academic sense the, pyramid = constant thickness, is true no doubt.  In the real world so many variables affect that, and change the whole equation. 

[DC]

I've seen your blog entry and I know the tiller stays the same. It's just the amount of taper I'm wondering about. I guess I'm wondering if wide or narrow might affect the weight distribution in the limb. So does the top half of a pyramid always have the same percentage of the total mass no matter how wide it is?
Selfbowman- for what I'm asking I don't think reflex enters in to it. In the real world, yes I think you're right.

[sleek]

It would be interesting to take a pyramid bow, tiller it out perfectly as one might get it, and take it to 50#@28. Shoot it in well so it's taken all its set.Then recurve it. See what difference in tiller and draw weight that make. Then bend the curves back out flat, and measure it's set and where it occured. Afterward,  bend the bow into a reflex/reflex shape, and see what affects that has on the bow.

All this to see what affect side profile has on a bow. Some yall can prob9figure it out just by thinking about it, but it would be interesting to see.

[DC]

I was kinda thinking of that but I was just going to do the one step. Make a flat straight bow, shoot it in and then reflex/recurve it. See how much difference there is. The bow I'm working on is Ocean Spray. I've heat treated it once and took out a little deflex on each limb. I either tillered off the heat treated wood or the correction pulled out so it might not be the ideal bow to experiment with. I'm going to heat treat again today so we'll see how that goes. I'm at 40#@20-21" so now is when the set really starts.

[scp]

I was kinda thinking of that but I was just going to do the one step. Make a flat straight bow, shoot it in and then reflex/recurve it. See how much difference there is.

That's what I always want to do with most of my selfbows. I have done that to a dozen or so, but I failed to measure anything, neither before nor after. As none of my several dozen bows are ever broken in, I can still do the experiment, one of these days. However there are many experts here, like Badger, who might have done it hundreds of times. So far as I can tell, they are saying that recurving the tips works but it has to be done early in the final tillering. Once broken in, doing so will just cause more set to cancel out the benefit. Still I have the nagging suspicion or wishful thinking that says we can recurve the tips at any time and doing so will be somewhat beneficial, within reason of course. Anyhow the simplistic but important question is how much benefit, if done properly. What is the maximum benefit, mainly in speed, we can get from recurving the tips as designed from the start, compared to making a perfectly flat bow with the same stave?

[sleek]

I'm probably going to do something just like this in a few days.