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Main Boards => The Bowyer's Bench => Topic started by: Art B on March 07, 2011, 09:09:00 AM
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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
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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..............
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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.
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That is why I choose to use sister billets.
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You're a smart man Roy! :readit: :D Art
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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?
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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.
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Ya need to get back to work is what ya need to do Son:)
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I am working Roy.......working on building better bows!
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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.
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Well Pat you and I think alike then.. But that Ole Art guy tells me otherwise..
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Well now Roy, I'm going to take that back 'bout you being smart :readit: :D Art
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Injun Giver:)
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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!
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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:)
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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.
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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
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Got pictures Trout? They board or stave billets? Like Art said, match the thicker rings together at the handle.
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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.
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Sorry no pics but they are just standard osage staves with relatively thin rings.
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To splice them for a full length stave, you need to z-splice or w-splice them together. You should do the splice on the thicker ring end of the staves. If you have the traditional bowyers bibles, there is a section in there about splicing.
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Trick is to get both limbs in the same plane. To do this you need to have the same plane on the back of the handle the same as the limb just outside the fade. Best to rough shape your bow limb and leave about a 5" handle section (both billets).
You can either eyeball your work if you have the eye for it or do like me and use a level.
I first work the belly down to where it's in the same plane as the back of the limb, level close to the fade, and adjust the plane of the handle using said level. Once both handle and limb show level you know you're right. Do both the same way, and once spliced or joined for a takedown, both limbs will be in the same plane.
For a takedown, get your handle section very dry. Last thing you want to happen is your wood to shrink later as it season/age out.........Art
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This is good stuff...
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Do you tiller 1/8" positive at brace or at full draw?
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just read this thread...reminds me of my hickory board stave I'm staring at.
One end has 4-5 fat rings and the other end has 10-15 thin rings.
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Brace.
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After Art explained to me what a sister billet was in a past PM, I can completely understand why and how it works. I've never done a splice in the handle, but a sister billet bow is in my immediate near future. :saywhat: :goldtooth:
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Once you get the hang of splicing you're never look at staves the same way ever again Semo.
Staves, with they often uneven working properties, can be more evenly matched by cutting into, swapping the lower stump end around, and spliced/joined back together.
Plus, the stump end creates problems with bending/curving unlike the top end. And since the stump end is stiffer/stronger/denser wood the bow will benefit by placing this section just outside the lower fade area where the bow receives the greater limb strain......Art
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This all makes sense but it is a little strange for me to think about bc I am so interested in finishing a true selfbow. The best part of it though is that I can find lots of good 40" staves but there is always a problem with the trees about 45-60". I will look at trees differently for sure. Lots more usable wood out there!!!
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So should you atempt to chace the same ring? Should you split before drying or wait? Any cool all wood dovetail type takedown systems? I have several new candidates for this that I just debarked and sealed.
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I've only used the metal sleeve system, but there are others out there, a search will surely turn up more.
If you're referring to green Osage, and you want to dry as quick as possible, I would suggest that you rough shape the limbs close to bow dimensions and seal 'em all the way around really well. Put behind your bedroom door and forget about 'em for six months. You can dry 'em faster, but fresh made bows can turn into a disaster later on......Art