Tillering Advice & couple of questions.

[mwosborn]

Here is one of the bows I am currently working on.  Hackberry static curve - 64" ttt, 1.75" to midlimb then currently tapered to 3/4".  Stave was cut and sealed in 2011.

Pictures are at a brace of 4.5" and then drawn to 13".  Currently 36# at the 13".  Final picture is immediately after unbracing.

This is my first static and I am going very slow with the tillering.  Have been very careful to keep limbs bending very similar as I reached this brace.  Have not exceeded 40# and have slowly exercised limbs after each wood removal.  It looks to me that the outer 1/3 of the limbs need to be bending more - wanted to get opinions on this as I not sure on a recurve like this.  What you think?


Secondly, the limbs are starting to take some set (even being careful)  the right limb more than the left.  My original plan was to make an unbacked bow.  However, it looks as if I might be better off putting some sinew on the back.  Opinions on this?  I need to get to 27" draw and I am shooting for a 45-50# bow when finished.

I plan on narrowing the tips when I get closer to finished - will be asking questions about this if I get that far.

Thanks for any help!

Mitch

 
 IMG_0130  by  mwosborn1 , on Flickr

 
 IMG_0132  by  mwosborn1 , on Flickr

 
 IMG_0131  by  mwosborn1 , on Flickr

[red hill]

Looks pretty good, Mitch. Did the limbs return to their original position after resting?

Also how'd you get the recurved tips? Steam or dry heat?

[heartlandbowyer]

Mitch
I'm far from being a selfbow expert but it looks like the right limb is week at brace but at draw it looks to be the stronger limb. Maybe get a shorter string on it. And it looks to need a bit of scraping on the outer 1/3 rds like you stated, left seems to have a little better arc then the right.

Cory

[John Scifres]

That's pretty short for a hackberry static.  Statics take a lot of the working limb away.  That being said, I like your design.  If you add some sinew to just the working portions, you will have a screamer.  

Tiller is fine for now but definitely get the outer half bending more, particularly on the right.

Also, if you are pulling 36# at 13", you are way heavy.  The correlates to over 70# at 27".  I'd like to see that closer to 25# before I began bending it much further.  That means taking some thickness off.  I'd do 20 rasp strokes over both limbs, 10 more on the outer half of each and a few extra on the right past midlimb and see what you are pulling at that same 13".

[mwosborn]

Thanks guys -

I went ahead and worked the outer portion of the limbs and it looks like it is bending better - will continue on....

red - the limbs did return some after resting - but not to their original profile.  I used steam to bend them - they bent really easy after warming them up.  I then let it sit for a couple of weeks before working on it.

[Roy from Pa]

Nice..

[mwosborn]

Thanks John - I am debating on adding the sinew or just toasting the belly or both.  Some say the 64" is too long for sinew - but like you say, the curves are taking away some of working limb.  Decisions, decisions.

[Dan Landis]

Mitch, did you do any heat treating?  I would definitely give the limbs a good toasting if you haven't done so yet.  Hackberry reacts well to being toasted.  I follow the instructions in the TBB Vol. 4.  It's the only way I've been able to build a low set bow with hackberry.

[takefive]

I don't know anything about statics but that is one cool looking bow.  Love those recurved tips.