Think Small

[UserNameTaken]

I'd really like the village elders to chime in on building small diameter sapling & branch bows. And, I'm not talking about 2" "saplings". I'm talking about sticks that are 1 1/4" and less. Some of the denser woods like Plum, Osoberry & Ocean Spray can obviously pack a lot of power into a very small package, and I like that. I like simplicity. Unfortunately, their bigger brothers are always stealing the limelight, and it seems like there's very little information on how to build powerful bows from small branches.
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Some questions that I have:

How do you deal with the extreme taper that some of these small staves have? Do you taper the fatter side to match the narrower side, or do you just take more wood from the belly of the fat end?

What are some possible layouts that you could use? What should the profile look like? I envision something that looks like a little needle.

Possible dimensions?

How short could you go with say a 28" draw?

What would decrowning accomplish? and can you decrown without backing? What if I decrowned & backed with flax fiber?

How would you best apply Tim Baker's mantra, to a 1" sapling?

The best wood for these small bows seem to check badly. If it checks, can I still use it?

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I'm really inexperienced with this whole bowyering thing, and I'm finding that I'm not particularly talented when it comes to tillering. It's in everybody's best interest to make sure that I figure this stuff out soon, because I'm destroying lots of perfectly good bow wood in my quest for knowledge. Please, help me stop the madness! 

[johnston]

This was my first year collecting bow wood and a lot of my stuff was small.
Also I often cut 1" stuff on purpose for practice or just lite bows. With the
right wood it may be possible to build "powerful" bows out of small diameter
pieces but a lot would depend on length of the bow and your draw length.

I taper the large end and leave the high crown doing all tillering from the belly.
Bendy handle D bow and the handle is treated as part of the limb so the
whole bow is arc of a circle.

Posted one a while back.

http://www.primitivearcher.com/smf/index.php/topic,28769.0.ht

Lane

[mikekeswick]

Good questions!
De-crowning on small branches is a good idea if the wood isn't particulary strong in tension. If it was elm or another tension strong wood then leaving the crown intact would be a good idea.
To get the most weight it's best to keep the limbs full width until say 8 inches from the tips and then start the taper to the nocks.
The densest woods will give the most weight when you are limited to width.
Labernum if you can get any makes great narrow/deep bows (like yew).
If one limb is wider than the other reduce it's width to match the narrower limb, if you don't you will end up with one limb thinner than the other - this means it will weigh more = handshock.
If you have problems with a certain type of wood checking then keep it somewhere humid and cool to slow the release of it's moisture. As the moisture content drops so you can speed up the drying process.
Good luck.

[JackCrafty]

How do you deal with the extreme taper that some of these small staves have? Do you taper the fatter side to match the narrower side, or do you just take more wood from the belly of the fat end?

I shape and taper the fatter limb to match the skinny limb exactly.

What are some possible layouts that you could use? What should the profile look like? I envision something that looks like a little needle.

Cross section depends on the properties of the wood.  Flat is best (rectangular cross section) but if the wood is particularly strong in tension or compression, you can leave that side rounded and then flatten the other side.


Possible dimensions?

1" wide handle tapering down to 1/2" or 3/8" tips.

How short could you go with say a 28" draw?

About 60" would be a good minimum for a sapling bow (with no reflex) with 28" draw.

What would decrowning accomplish? and can you decrown without backing? What if I decrowned & backed with flax fiber?

Decrowning helps prevent the breaking of a bow that is made of tension-weak wood.  Yes, you can decrown without backing if the bow is long enough.

How would you best apply Tim Baker's mantra, to a 1" sapling?

I'm not sure I remember what that is.  All I can say this that if your sapling is taking a lot of set during tillering, you are straining the wood too much.  Either the back or the belly needs to be flattened.

The best wood for these small bows seem to check badly. If it checks, can I still use it?

Yes, you can use it but it's risky.  Wrap the split areas with thread, cordage, sinew, or rawhide.

[UserNameTaken]

Hey, thanks guys. You cleared up a lot of my uncertainties. Now it's time to go destroy--I mean make--some bows.  That's a great looking bow, by the way, Lane.

[Keenan]

To understand decrowning think of it this way.   All bows have a neutral plane. That is the point where the wood is changing from tension wood"Back of bow" to compression Wood "belly of the bow"  In each bow it can vary depending on the shape of the limb cross section.  If you were to look at an extreme example of a heavy crown , think of a triangle with the peak as the back of the bow and the flat bottom being the belly.  If your limb profile looked like this and you bent the bow, the peak would be under the most tension,  and the belly very little compresion because of surface area sharing the forces.
 Now if you invert that extreme example and have th point as the belly and the flat of the triangle as the back of the bow. The tension would be spread out over a larger area and the belly would surely crush from not enough wood to balance the force.
 This is why some type woods will work better with certain designs. Hope that helps