AZ Ironwood Bow

[richgibula]

Next to the right:

[richgibula]

This is a composite for clarity but the details are hard to see:

[richgibula]

I plan to cut a section, following the grain for about 34 inches. Then cut it in half longitudinally to make 2 pieces 1 1/2 inches wide and do a half-lap joint at the handle end with a couple of dowels. Then I have to decide about the backing.

The remaining question I have is the bow arm thickness.  Does anyone have an ideas about that with such hard wood?

[joachimM]

bow limb thickness: that's just the whole process of tillering. Take off wood, bend, indicate where you need to remove wood, repeat. If you're gonna back it: 15 mm is more than enough thickness for any bow. You'll probably end up at around 1 cm.

But honestly, this looks like a hell of a difficult project for a first bow, with wood you don't know is even any good for a bow. Yes it's extremely dense, but that doesn't make it better as bow wood per se: it just means it allows narrower limbs. Which isn't necessarily easy. I'd put it away, make a bunch of regular bows first, and then maybe look back at this piece.

my 0.02 €

[richgibula]

Thanks JoachimM.

I have made a bow from laminated bamboo and a mesquite bow before.  The mesquite bow was 68 in and has an over 65# draw.  I had to use fiberglass backing because it could not be used without a very strong backing.  I wanted to have a little less draw weight since I have developed a muscular disease that makes this bow hard to use. I wanted to prepare the wood better and learn to follow the grain. 

This is the mesquite bow pic.  I wasted a lot of time and mesquite to make it.  I was hoping to do a lot better with the Ironwood.

[richgibula]

Another question is: what is the best taper?  I was of the impression that softer woods will work best with the taper #1, that is, right at the end and the hardest woods should be the slowest taper (#3).

[willie]

for a bow limb to bend evenly or to be stressed equally and not be overstressed or hinged at any point it must be tapered

tapered in width or tapered in thickness or some combination of both.  changing the width taper only means you will have a different thickness taper to get the stress even.  this principle is a mater of physics.

whether the wood is soft or hard, strong or weak, brittle or elastic all affect the thickness or width or limb length or draw length
ie a characteristic of materiel qualities

[richgibula]

Thanks for the reply willie.  I understand the physics and tillering concepts.  I was thinking that there were recommendations based on the wood type.  I have seen people make bows out of very soft wood but they would make wider and longer bow limbs to increase the mass to generate more recoil from the draw.  I thought that there were reverse concepts for very hard woods.

I tried to review the pics of osage bows on this blog.  Since that is a hard wood, I thought that the designs would have something in common with what I am trying to do.  Unfortunately, most of the pics were removed and I was not able to see too many successful construction images.

[richgibula]

I have. been reading around and wondering if, since it will be hard to follow a growth line, should I shoot for a wider bow rather than a more aggressive taper?

[richgibula]

3500+ views and no more advice?

[willie]

I think I understand your concern about thickness tapering the ironwood, if you mean that it might expose more grain runoff in the already wavy ringed ironwood.

if you made a bi-lam with the ironwood belly at 3/16 to 1/4 ", and had a hickory board lam for the back.  you could start with the hickory at any thickness and tiller from the back

 pryamid would require less thickness taper and might be preferable

[richgibula]

Thank you willie.