Author Topic: Laminate ELB question: Should I just do a pyramid taper for the width profile?  (Read 1629 times)

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Offline toomanyknots

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The profile I have been using for a typical elb is:

76" from tip to tip
1 1/8" wide for 3 1/2" on each side of center, tapering from there to 3/4" wide 6" from the tips, than taper to 1/2" nocks for the last 6"

The thing is, no matter what woods I use, or how much I do or don't reflex the stave it seems, the outer tips are always very very stiff. Which of course I will then have to correct. I've heard Ian on paleoplanet (I think the same warbow making Ian on primitivearcher? ) say that laminates don't require the same type of taper as a yew bow. I adapted this profile I use from a general 100# @ 32" yew warbow design, I just scaled it down a bit. So have I been using needlessly making my profile wider at the outer limbs than I need to? Because tiller wise it sure seems so to me? The woods I use are hickory or ipe for belly's, maple or bamboo for backings, etc.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
The width doesn't make as much difference to draw weight as the thickness (Yeah I know that you know that), but it does add to the stability and lack of sideways bend.
I tend to ignore the width profile (generally it's parallel for say 6-8 inches then taperd to the tip when roughed out) until I'm pretty much finished and then I blend it in with the nock to to make it look a smooth curve. (I hate those longbow tips that look like someone has just done it with a giant pencil sharpener and plonked a block of horn on it, and no attempt to blend from circular at the nock to the limb profile.).
What I'm really saying is use thicknes taper to give the tiller you want, and width taper to make it look stylistically how you want.
Hope that makes some sort of sense?
Del
Health warning, these posts may contain traces of nut.

Offline toomanyknots

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The width doesn't make as much difference to draw weight as the thickness (Yeah I know that you know that), but it does add to the stability and lack of sideways bend.
I tend to ignore the width profile (generally it's parallel for say 6-8 inches then taperd to the tip when roughed out) until I'm pretty much finished and then I blend it in with the nock to to make it look a smooth curve. (I hate those longbow tips that look like someone has just done it with a giant pencil sharpener and plonked a block of horn on it, and no attempt to blend from circular at the nock to the limb profile.).
What I'm really saying is use thicknes taper to give the tiller you want, and width taper to make it look stylistically how you want.
Hope that makes some sort of sense?
Del

That makes perfect sense. I guess I'm actually not making any though, :) , I forgot to say that I am cutting the taper to these staves on the width and belly, rounding the edges, and then when I go to floor tiller this is always what I get, tiller wise. I taper the belly from around 3 1/2" from center to the 1/2" tips in a straight line. It's funny though, after posting this I thought, "why don't I just go measure a pre-tillered bow's width taper, and then copy that?". So I went and measured a finishe bow I had, and the width taper is exactly the same. I think I might of brought the stiff outer limbs around though by reducing on the belly mostly, I don't know,  :o. I guess what I am shooting for is as close to a pre-tillered bow as I can get to after cutting all the tapers and rounding the belly, etc. On my bows though, I think it ends up a lot of the time something (roughly) like this:



Yes, it is a horrible picture that tells you nothing really. :) But it's not really a straight taper anywhere is what I mean, it seems to always come out a curved taper. I made a template which was a straight pyramid taper for both the width and the thickness, but I think it resulted in the mid-limbs being way too narrow.

EDIT: This is what is roughly what my tiller looks like on every bow the first time I check the longstring tiller: (I go right to longstring tiller anymore and skip floor tiller, with roughed out laminates it seems I don't need to really like with staves)



I'm thinking I need to reduce either the width or thickness or both on my template on the outer limbs. I know templates will only get you so far, and the rest of the way only good ol tillering will take you, but I am just not super happy with the results I am getting, and I think I can easily get closer to the tiller shape I want.
« Last Edit: September 08, 2013, 08:30:47 pm by toomanyknots »
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline adb

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I make all my laminate ELBs with continuous tapers from a parallel 4" grip to 1/2" tips, regardless of grip width.

mikekeswick

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The width taper you are using is what i've used on hundreds of elb's.
The mistake most people make is not making the tiller elliptical enough.
You say the tips 'always come out stiff'....well remove some wood there then  ;)
Go back to basics.....no thickness taper = circular tiller              thickness taper = elliptical tiller       lots of thickness taper = a more extreme ellipticaL tiller.
People imo get stuck in the elb must be tillered circularly notion.....well this is tosh...the thickness taper or lack thereof determines what the tiller should look like....end of story.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Just thowing ideas here...
Sounds like maybe you are doing too much before tillering on the tree, and expecting it to be right from the start? Or maybe just not taking enough off the tips for fear of coming in under weight?
Mike nails it...
"You say the tips 'always come out stiff'....well remove some wood there then  ;) "
It's just good ol'  back to basics.
If you don't want to make the tips any smaller, then maybe just go up a whisker on the thickness along the rest of the bow at the lay up or rough out stage?
Laminates not my bg, but out of interest do you use tapered cores?
Del
Health warning, these posts may contain traces of nut.

Offline toomanyknots

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You say the tips 'always come out stiff'....well remove some wood there then  ;)


Well that makes sense, :).

I make all my laminate ELBs with continuous tapers from a parallel 4" grip to 1/2" tips, regardless of grip width.

Duly noted. I will try that out myself, thanks.


Laminates not my bg, but out of interest do you use tapered cores?
Del

For the most part no, usually they are around 3/16" thick. Although, the ends do usually end up a tiny bit tapered just naturally from the way I flatten them on my little belt sander.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair