Wood longbows.. some completed pics and a few questions

[Bradford]

So I have made 5 youth longbows.  All with Hickory for front and belly with an accent strip in the middle.  I have made 4 - 48" and 1 - 56".

3 came out great and work wonderful, 2 broke.  The two that broke where both made with Walnut for the center strip and and handle.

I have been gluing 3 strips together with tightbond 3 glue.

Is it because the Walnut?  or am I doing something else wrong.  The first break was my fault.. I bent it to far back.. but the second break happened after shooting it multiple times with no problem, then pulled it back a couple more times to exercise the limbs and "blam"

Anyway.. any help would be appreciated.

 

 

 

[macbow]

From the strung picture. My thoughts are,it,is bending way too much just out of the fades. And this is without it being pulled at all.
From the picture of,the break that is the same general area.

Did you use a tillering gizmo ?

It looks like the thickness is the same all the way through.
If this is the case the only tillering is,the taper in the limb width.
More of a pyramid shape that is a,little,wider,at fades and much narrower at tips would,help a little.

Other wise wood need to be removed from past mid limb towards the tips on the belly.

Pretty wood combo.

[kennym]

I'm with Ron, needs a power lam and some more taper in the lams.....

[vanillabear?]

[Bradford]

thanks guys.. the strung pic is a 10# bow and shoots well... but yes.  i am using the binghams design for these, and all the lams are te same thickness with the taper in the pyramid.  I will start adding a power lam to them.

[macbow]

I'd suggest the power lam go well beyond the fade.

[Mike Most]

One thing you might consider, in using binghams patterns, I believe they are made as a design for glass and wood bows. If you are using only wood, I would look for some designs that have a more substantial thickness in the fade area.

Just my 2 cents,

Mike

[Bradford]

The other thought then.. could I taper my center strip instead of adding the power lam?  would this do the same thing?  Or should I do both?

Thanks

[Pat B]

It looks, from the pic you posted of the broken bow, like the back failed at a run off in the backing grain. I don't think it was necessarily the core material you used. For backings especially you want to use wood with good grain configuration, ie. straight grain with few if any runoffs and if it has runoffs they should not be too drastic.

[DVSHUNTER]

I agree with everyone else here. I would try tapering the core and also beefing up the fades a bit, but at that light weight, tapering the core to move the bend out away from the handle will help quite a bit. Pat nailed the break on a runoff, but I think that the hickory would have held if the limbs were sharing the stress a bit more equally. Nice looking bows non the less though.

[Bradford]

Cool.. thanks guys.

That is why I am laminating these.  I figure it will help with holding them together.. and I was right.  That one broke in my hand on pull back.. scared me, but did not blow up.  So I am sticking with the lamination's.

I feel that you will always have run off when you cut an angle for the limbs.. logically if you have straight grain and you cut at an angle, you are gonna have some run off.  

I will beef up the fades and taper the core on this next one I am starting today.  It only needs to be around 15#, so I should be good.

I will post and let you all know.

[Crooked Stic]

A little bit of deflex in the riser would help also.

[So-Mo Archer]

I'm with the rest, you need more 'meat' near the fades. The bows are beautiful though, and would make my kids slobber and giggle. On your next try, I would suggest starting your taper around mid limb, that should help spread the load more evenly. FWIW.

[Bradford]

I just made the core tapered today.  I will glue up tomarrow.