HICKERY

[Buck Buckley]

I would like to know if I can use hickery on the belly of a bamboo jataba bow instead of osage I always make my osage .150  would hickery be the same in .000 thanks BUCK

[LittleBen]

You COULD use hickory instead of osage, but it is not the better choice.

Hickory is stiffer than osage, but less elastic.

IF you go to hickory instead of osage, I would say you'd need to go slightly thinner on the lamination .... maybe by 5-10% ... so say .140" thick.

But I would also go wider, so if your osage bow is 1.5" wide, I'd go at least 1.75"+ for hickory.

Tell us more about the bow you're making ... why use hickory instead of osage?

If you're out of osage, but you have bamboo, hickory, and jatoba only ... I would make bamboo back, hickory core (I know it sounds crazy), and Jatoba belly.

Hickory is much lighter than Jatoba, and Jatoba is much better at handling compression on the belly.

In general the core lam should be as light weight as possible ... it doesn't comtribute much at all to the draw weight, and it just adds mass to the limb if you use something very dense.

I'm a believer that for a tri-lam bow, ipe (or even jatoba) is really hard to beat especially with a light weight core lam like maple or cherry or walnut. I think hickory would be fine for the core if you don't have those available.

Alot of people say jatoba is prone to fretting, but I have not found this to be the case ... ever ... and I've made a number of them ... the most extreme is only 58"ntn static recurve 55# @ 26", with a 20" long riser and fades ... so less than 20" working limb only 1.25" wide at midlimb ... it has no frets ...


tell us more about this bow and your materials available.

[Zradix]

Nice to hear about your exp with jatoba Ben.
I've been looking at it as a more affordable alternative to osage....jeez I wish ipe and my skin got along...lol

I don't have much exp in bow making but from what I've read I agree with what you said above 100%.

I would add a sideways question/comment though...
If using the boo as a backing with the jatoba belly..I'd think you'd want to get that boo pretty thin to keep from over powering the jatoba. which at the same time will move the hickory into a little more tension vs compression.

...would you agree?

[LittleBen]

So here's my take John,

Thinning a backing is not nearly as effective as narrowing the backing by trapping. This is because the outer surface of the limb does most of the work, and experiences the highest stress and strain.

When you thin a backing, what happens is exactly what you mentioned ... some of the tension work will just be done by the material under the backing ... and the reduction in tensile strength will be minimal unless your core material has almost zero tensile stiffness.

When you trap the back, you are actually reducing the width of the outer surface of the backing. This should give you a nearly linear change in tensile strength .... so trapping to 3/4 of the belly width, will leave the backing 3/4 of it's original strength.

By comparison, thinning a backing to 3/4 of it's original thickness would have nearly zero effect on the strength of the backing.

If you're going to get really extreme and thin the backing down to a paper thin layer, I believe it can work, but trapping is mathematically a superior approach ....

not to mention, if you thin the backing ... then you just thinned the backing and thats that ...

but trapping can be done later if needed after glue up ... you might decide not to trap at all ... or you might decide you need more trapping than you originally did ... either way it gives you more flexibility.

With all that said, I rarely if ever bother trapping backings or thinning them down much. I just tend to make my bows a little wider than absolutely necessary, and that will reduce the surface stress on the belly AND the back ....

[Zradix]

Thanks Ben...makes sense.

I have heard the theory. And it seems valid to me.

I have wondered though, if you're backing a core/belly that NEEDS to be backed ( not great grain etc )  I've thought there may be a higher possibility of the exposed wood of the under-layer to splinter since it's sorta becoming the back in the trapped area.
...sorry if this is too boderline hijacking

[Buck Buckley]

BEN I made alot of bamboo baked osage  with jataba core My bows ar 1 1/4  at the fades taper to 1/2 64 to62 inches long  my bamboo is 1/8   MY jataba is planded to .300  then i equaly diff in half then I take one half and diff it in 3 pieces  I THEN RUN IT THROUGH MY EDGER  run it to my first mark  start over and run it to my  2 nd mark  and do the same thing over to my 3rd mark  and then do the other side the same way that will give you a taper on both sides. my osage  .150 for a 62" .160 for a 64" the reason I WOULD LIKE TO TRY HICKERY IS I got a out let for ir  BUT I want to make sure it will work

[LittleBen]

Yeah hickory will definately work, but I think you'd be best advised to go quite a bit wider.

I'd go for between 1.5 and 1.75" wide, I know that seems like alot, but you can always narrow later.

You could also go for bamboo-hickory-hickory. The possibilities are endless.

Hope to see some pics of one of these guys finished up!