Primitive Archer
Main Discussion Area => Bows => Topic started by: bigcountry on February 07, 2014, 01:49:59 pm
-
I have a friend that says do not make black locust bows real wide. He has built a few. I always heard, 1 3/4" for BL. But what he said makes sense. He says with a high strength tension wood, you want to limit the backing width so the belly won't be overpowered. wider the backing, more chance it will overpower the belly, narrower, the belly will be thicker.
Any ideas? I do plan on heat tempering.
-
Locust is very strong in compression but is brittle so it has a tendency to fret if not tillered well. I think 1 3/4" is a good width to start with. You can always reduce the width if you find the limbs are getting too thin. Another option that goes along with what your friend says is to give the limbs a trapezoidal cross section with the belly wider than the back. This will reduce the tension strength some and give more compression strength compared to a rectangular limb cross section.
Locust also reacts well t belly tempering for more added compression strength.
-
My experience is that yes, it has a high compression strength, such that it could stand next to osage, but it's also got an overwhelming tension strength and brittleness that make it less stable as it gets more narrow. I've made a couple almost-successful one inch wide seventy inch long bendy handle trapped back BL bows, but I could tell from the start of the builds that while the bows would be fast they wouldn't be terribly long-lived.
They're dead after a few hundred shots, chrisaling all up and down the bows telling me it wasn't poor tiller but bad design for as much weight as I had (around fifty pounds each). Maybe if you keep it closer to thirty it'd stand up to the weight, but you're probably better off starting wide and flat and just narrowing as you go.