Decrowning osage?

[sami bow]

While working Hurricane damage in Ohio last year (I am an electrical lineman and hurricane Ike jumped north and took out a bunch of trees in Ohio) anyway, around Zanesville I picked up a couple of straight osage branches about 4" in diameter.

I sealed the ends and waited a few months, then yesterday started working on them.  I have mostly worked split staves made from an upright tree, and understand the tension wood on the top of the branch makes the best bow.

One stave has a crown or ridge on the top and if I were to use it as is, it would have the crown of about an  inch and a half circle. That would put a lot of tension stress in a small area.

My question is, does it pay to go to the trouble to de-crown such a stave and will I have to back it with sinew, rawhide or something?

The other option is to make a kids bow out of it.

[tom sawyer]

I've seen selfbows with that much crown.  Osage is good enough in tension to withstand it.  its strong enough that you can make a 50lb bow out of a 1" wide piece, going narrow and pushing the thickness will reduce that crown.  I'd leave the belly a little flatter than the crowned back, that'll push the neutral plane a little more towards the back and alleviate some of the problem.

I've seen very few decrowned bows, theroetically you can do it and make a selfbow but I think a backing is a good idea.  I love sinew for a short bow, it adds significantly to the performance.  Rawhide looks cool but is just for protection.

[Ohio John]

thats my neck of the woods!  If you come on any more osage and need some help look me up

[sami bow]

Hey, Ohio john,

We drove from northern Minnesota to work storm damage there for a couple of weeks last year. I wish I would have had time to look for more wood.

Thanks for the advice, Tom sawyer, I believe I will make a narrow bow out of the stave and see what I can get.

[George Tsoukalas]

I'd just leave it an inch or 2 longer than you normally would. Jawge

[sami bow]

I forgot to mention that the stave is fairly short, I believe, 62" or so, so I will have to make it bend thru the handle.

[sami bow]

So far i have it rough tillered, straightened the crooked spots, now i have to tiller it to desired weight  (60Lbs @ 26") it is barely an inch and a quarter wide at the widest, tapers to narrow tips andlimbs are about 1/2 inch thick, and it is so strong it's just barely floor tillered. Strongest piece of osage I have worked with.

I didn't decrown it and am keeping the belly flat

[George Tsoukalas]

Let us know how it works out. Jawge

[sami bow]

I forgot to mention that it was only 58" from nock to nock. I started getting a lilltle temporary set in the limbs, while tillering for 60 lbs., So I decided to go for a lighter weight on the highly stressed limbs. I had a nice circle tiller, just barely bending in the handle, so I started shooting it in at about 55 lbs. After about 20 or so shots I inspected the bow and found a fatal crack in the belly , right by an area of especially high crown in the back. The belly crack did not look like a compression fracture, but must've cracked when I was heating and straightening it, and I didn't see it till after shooting. good thing I didn't have the horn nocks finished. Sure wish it had been 62 or so inches long.

Another lesson learned from a questionably short , high crowned stave. I am picking out a nicer stave for my next go-round.

FYI, I have been successfully making bows for at least 17 years, but, havn't had much experience with short, high crowned osage branches.  I have made over 100 bows and broke about a dozen or so. (usually too short) always learn something from a broken bow. (even if it feels like a punch in the gut.)

[koan]

Sami, if the crack is longitudinal you can fill it with superglue and keep truckin. If your are done tillerin you can wrap the crack with silk thread and soak it in glue....Brian

[sami bow]

Three cracks across the limb and about 1/3 of the way through, in about an inch and a half area. I will cut out the area, do a belly patch and re-tiller for one of my nieces or nephews. with the high crown and short length, I should have tried for a 40-45 pound bow, should've known better.

[sami bow]

Soaked the cracks with super glue, rasped all the way through them and re-tillered the bow. The cracks were not as deep as I thought and the bow tillered out at 42 lbs. shoots pretty good.

A little set due to overstraining at the higher weight, but a sweet shooter anyhow.