A new 54" TTT symmetrical one piece core ready for some gemsbok horn with some longer regular handle fades [3"] fadeing nicely into the the limbs.Overall 10" handle.11" working limbs with 11" stiff outer contact recurved levers.Thickness composed of 40% core,30% horn.30% sinew/glue.Going for a 28" draw and around 50#‘s.
As you know I foolishly broke the 52" bow.
Took some references from Adams’ book about profile for more efficient outer limbs.Putting more core reflex in the right places before sinewing.I bent my recurves in two stages.Once at the beginning of the outer fade or kasan eye and then 6" farther another bend 3" from the tip.
I have 2 types of hickory around me.Mostly shagbark and some pignut also.Pignut as a general rule can be slightly denser,but not much more.Usually in the .78 specific gravity range.
The core from this pignut is dense with around 30 rings to the inch.I can notice the difference with the same parameters when weighing it.Almost like osage but not quite…ha ha.
Horn is on and thickness and width limb matching is established.Ready for sinew.Looks like only 2.5 mm sinew is needed.Just a little over 2 ounces I figure.
I figure to reflex this one to 12 or 13 inches making it more user friendly,but still get the performance I like.It’ll begin to have the boat look when reverse braced and after sinewing.
I pay attention a good deal to mass weight also when zeroing in on my draw weight with a build.
8 ounce core,40%/+3.5 ounce horn,30%/+3.5 ounce sinew and glue,30% puts me right at 15 ounces on a 54" TTT bow.Enough core to make tillering more stable.Very close to where I want to be for +50#'s.
Very interesting Ed! I see very similar measurements on the core and horn thickness on some of my builds. Almost identical actually! Looks like I may be on the right track for a 50# bow. Love following your builds. Lots of info. On my current Korean build I kept my outer third of limbs are little thicker but only slightly. My hope it to get the bend more concentrated mid limb and then get last bit of bend in the outer limbs at full draw like similar to a Turkish or ottoman bow. My hope is to get that longer draw I’m after. Thanks for posting Ed.
Cool.
Long ago for me it helped to understand the stress dynamics along the length of the limb stated by Tim Baker in the TBB series books.There is’nt much stress on the far outer limbs so they can afford to be narrower and lighter…increasing performance.
At least on these longer versions of horn bows anyway or any regular bow for that matter.
Still a fair amount of bending needs to happen on the inner limbs to keep the string angle low at full draw with no stacking.
I’m a bit envious of your access to all those different hickorys and other hardwoods! If i want a true hardwood i need to go to lumberyard…hah.
Its a selfbow heaven in the north america - at least compared to Finland.
We have similar procedure when it comes to measuring the core! I draw lines and compare difference each 2" . Works really nicely. And allows you to measure sinew thickness in finished bow. Thats really neat.
Yes it’s check points along the whole way with construction.Then it’s always satisfying when it works out to the good.
I’ve tried the specialty lumber yard in the past with the exotics.It takes a good eye to come out of those places with good material.
I like air drying it slowly so I usually cut a lot of logs for many staves over years to over supply enough to get to work with continual dry wood.
Even though the culture here in my area is’nt for making and shooting flight bows I’m always impressed by those pushing the limits of their craft.That’s when the term unlimited really means something.
Just through with 3 courses of sinew on the pignut bow.Around 2 ounces of sinew and 2 ounces of hide glue.A scooch over 2.5mm thick of sinew.It will be at least a 50# but not over 60# bow.
Got to use the 250 grains of 22" long sinew as the last course.Put it on in 3 strip sections onto each limb crowning it slightly while applying it and overlapping at the handle making a nice swell bulbous feel to the handle.Very little filing will be required.
Reflexed a little after each course up to 12" to the back of the limbs.
Some slight imbalance between the limbs but not much.I did not get the core as evenly matched as I should have for that.Nothing out of the normal for me…ha ha.Tip alignment spot on though.
I’ll correct everything whlie tillering probably 5 months from now.
Onto the next project.
