Uneven limb properties

[Art B]

I decided to bring this discussion over from another thread.

Seems as though many bowyers see a piece of wood as, well, just a piece of wood. Never giving any thought to even or uneven limb working properties. Here's a little something I copied from Torges' article "Tillering the Organic Bow".

Torges wrote: As an aside, this might be the place to mention that the reason sister billets were preferred by past masters over full-length staves is that the wood is nearly identical limb to limb. Its working properties therefore are nearly identical. By contrast, if you sift through a stack of full length osage staves you will discover in each one dramatic differences in the growth rings from one nock end to the other. Selfbows of ring porous wood seldom resemble each other not only when made from staves taken from the same tree, but even within themselves, from one end to the other in a full length stave. It may be easier to build a bow from a full length stave rather than having to join sister billets at the handle, but it is simpler not to.

Your thoughts!  Art

[JamesV]

I always thought the tillereing process made the limbs equal out. Are you suggesting that although they will bend the same they might not perform the same. This is a very interesting point, will be glad to see the replies from the builders that know.

James..............

[Pat B]

I think one thing Art is referring to is the difference in ring thickness from one end of a stave to the other. Think of the tree as it grows. It tapers from bottom to top. The closer you are to the stump the thicker the rings. With sister billets you split a billet in half lengthwise and splice the butt ends together. This give you the approximate same ring taper for both limbs.

[Roy from Pa]

That is why I choose to use sister billets.

[Art B]

You're a smart man Roy!      :D   Art

[Roy from Pa]

Yes I am Art, now if I could only understand the less positive tiller for 3 under, I would be a genius:) LOL  

Pat, what are your thoughts on positive tiller for 3 under compared to split?

[PEARL DRUMS]

Roybert has you guys all fooled!.........oddly enough Im half way into my first osage self bow and was wondering about what you just typed Art. Not having much self bow knowledge I didnt know what I was thinking, but I could see it and it made me quit tillering for the day until I figured it out. I wondered how a full length stave with different characteristics from bottom to top can be made to bend the same and deliver the same power and tiller timing? I need to pay attention to this thread.

[Roy from Pa]

Ya need to get back to work is what ya need to do Son:)

[PEARL DRUMS]

I am working Roy.......working on building better bows!

[Pat B]

Roy, my brain doesn't allow me to get into the how and why of building bows. I just build them and let you brainier guys do the figureing. When I have thought about 3 under it seemed to me that the bottom limb should be stiffer. Apparently that isn't the case.

[Roy from Pa]

Well Pat you and I think alike then.. But that Ole Art guy tells me otherwise..

[Art B]

Well now Roy, I'm going to take that back 'bout you being smart      :D  Art

[Roy from Pa]

Injun Giver:)

[PEARL DRUMS]

I tiller my top 1/8-1/4" positive for sissy pants 3 under shooters. The bottom limb gets pulled the same distance on a shorter string. Take it for whats its worth Royboy. I feel like this thread got hi-jacked........Art's gonna come gunning for us!

[Roy from Pa]

1/8th would be plenty for your sissy pants 3 under shooten Pearly Boy:) I ain't skeered, don't think Art could catch me:)

[TroutGuide]

Tell me more about these sister billets.  I have the perfect pair, wood borers ate the other end.  So how and when do I splice and what about a takedown version?  I was already mulling over trying to do this with these pieces.

[Art B]

With billets, just butt the stump ends together. Most of the time it's fairly easy to tell which end is which. Just match the thicker/larger rings in the handle and use the smaller/thinner rings for the tips........Art

[Roy from Pa]

Got pictures Trout? They board or stave billets? Like Art said, match the thicker rings together at the handle.

[TroutGuide]

They are staves that are too short to buid a bow with due to damage.  They are about 40" long and split form the same log, side by side.  So what is the process of splicing or what is the best way to build a takedown with these.

[TroutGuide]

Sorry no pics but they are just standard osage staves with relatively thin rings.