True or False?

[Badger]

  " A pyramid bow of equal thickness will always bend evenly regardless of starting width"

      I honestly don't know the answer, a good friend of mine and prominent respected bowyer insists this is true. I usually but not always find myself tillering out the pyramides with a slight taper. My belief is that the closer I am to the right demensions the less tillering it needs. He does awknowkedge that not wide enough will take set or break so we are not really that far apart to begin with.

[PEARL DRUMS]

Depending on the woods origin, i.e. stave or board. A stave could vary too much in other ways to hold a thickness tip to fade. A board? I cant see the thickness changing anymore than .020-.030" with most cuts.

[bubby]

pretty much that's true, but nothing is absolute, I build a lot of pyramids and they all start out even, and they bend pretty even right off the bat but to get a great tiller I think they end up with just a slight taper, slight

[bushboy]

Because it's wood,nothing is always totally uniform.

[nakedfeet]

You know, I've read this so many times.

I think the catch is that it's not quite possible to have a perfectly triangular limb. It would have to end at zero width and the string would have to attach there at the very end. Of course that's impossible. Even on the narrowest tips the zero point is a few inches at least off the end of the bow.

At least that's how I understand it.

With extra width you get closer because the angles are steeper, so it's slightly closer to truly triangular. Instead of the zero point being maybe 5 inches off the end of the bow, you're 2 or so.

[Hamish]

Depends upon extremes of the limb's width and or length. A really wide pyramid limb 3" and 30"(2x limbs /bow, 8"handle and fades, 68" btwn nocks) long is and a constant limb thickness is going to be bending a lot more(too much for a good tiller) in the mid limb and the tips and not enough near the fades. It would need stock removal from the thickness, nearer the fades to get a circle of arc tiller.
A pyramid bow limb 1&3/8" wide x 30"long with a constant thickness is going to be a lot closer to a good tiller than the first example.
 Always go by how the bow bends rather than what a theory states.

[George Tsoukalas]

True, it will bend evenly theoretically, Badger.

Problem is near handle wood that is wider has too bend more than the narrower outer wood to give a more circular tiller.

A bow with parallel limbs out to just past mid limb will have an elliptical tiller.

I think that prominent bowyer and I have disagreed a bit on that point.

Jawge

[Don Case]

I would make an assortment of limbs from PVC to prove the theory and from then on it's up to the differences in different woods.

[JonW]

I can't say for sure on boards because I don't use them. I have never had a stave bow have a constant thickness. A pyramid is my favorite style and I make them whenever I have enough width.

[JackCrafty]

   Watching this...

[toomanyknots]

It's been always true with me with board bows that have a straight profile. Laminates not so much, but maybe because I reflex them during glue up, and that might effect tiller. Or I also might do a small taper to the pyramid board bows and not realize it so much. With either bow I find fades are very important to keep the bow from bending off the handle.

[toomanyknots]

With extra width you get closer because the angles are steeper

True, the wider the fades start out, the better the tiller will be in my experience.

[bubby]

I've built a lot of pyramid board bows, cut the thickness on a tablesaw constant even thickness, most of the time after I cleanup the saw marks I go straight to full brace, good bends, but, and it's a big butt, by the time I have it finished if I mic it it will have a slight taper, very little is perfectly uniform with natural materials, bub

[mikekeswick]

EZC has it 

Watch the fades at all costs!

[Pappy]

I always figure with a stave bow [haven't done a board bow] that it gets me in the general vicinity of where I want to be,but not exact,never really measured if they have a slight taper or not,[probably do]    I just remove wood until it bends like I want. I never really do much measuring of anything after a stave is floor tillered. So Steve I guess the answer is True/Flase/some what true/some what false. You know that seemes to be the case in a lot of this wood bow building stuff.
   Pappy