Flatbow 'help-along'

[Eastman]

Good day all,

The exams are all over,it's summer vacation and I have time to make bows again!

So i'm hoping that you guys could help me tiller this bow so as to hone my novice skills. I'll be posting photos with every step of progress I make,kinda like a help-along.

So here it is: 'Mak sering' (i think it's called Chinaberry in english), 72t2t, with assymetrical limbs (both being 1 3/4'' at the fades)

[Eastman]

O.K. , in those pics you can see how assymetrical they are. I applied a Blesbuck rawhide backing (i guess it's like deer rawhide, thin and strong). Here's pics from the first tentative pull on the long string.

and I threw in a pic of a blesbuck just for fun..

[Carson (CMB)]

That blesbuk looks to have lots of good bow-making parts on em    I cant see anything wrong with that initial bend.

[Eastman]

I'm aiming for about 40-50# @30'' ( My draw is pretty long). I read that it's not very dense, so i guess it's best to keep it long and wide.
The thing is it's so hard to judge wich parts are bending too much with it being so crooked. But luckily for me, I got you guys to help me out.
Apart from going real slow from here, what else does one have to do with character bows to judge tiller?

Thanks alot

[adb]

Make your 'long' string much shorter... make it the same length as the bow. With your tips so heavy, watch that it doesn't just bend at the fades.

[George Tsoukalas]

You chose a challenging stave. it really isn't bending enough to tell anything. Jawge

[adb]

You chose a challenging stave. it really isn't bending enough to tell anything. Jawge

+1. You have profile taper, but no tickness taper. This won't allow even initial bend.

[RyanY]

I agree with what's said above. Keep a sharp eye on the thickness taper. Make sure it's nice and even with no dips or bumps along the length of the working limbs. Also make sure you floor tiller it well. Observe that the bend is even and has similar strength for both limbs.

[Del the cat]

You want a thickness taper of about 1.5mm every 6" just to get you started flexing.
Or decide on the thickness near the grip and what you want at the tip, subtract one form the other and divide by working limb length to give the taper .
Del

[k-hat]

What ryoon and del said.  Way to go mathy on us Del!

Since your limbs have differing reflex, you will need to
--shim up the side that is low until they are even, then bend and continue tiller.  Otherwise, you're going to overweaken the reflexed limb in tiller.  It will look the same as the other limb but actually be weaker. 
--Course i suppose you could leave it so that tip is always just above the other and make that the lower (stiffer) limb as well, since there's not a ton of difference. 
--OR, you could heat in a little more reflex on the other limb so they match

IF you've properly floor tillered and checked taper, you should make your tiller string so you can just barely get it on the bow and it lays snug against the belly.  Otherwise your tips will look too stiff and the inner limbs too light.  You may even be able to very low brace it (2 or 3") and check the tiller.  If it looks ok then you could flex it some and adjust from there.

As far as the wavy limbs, I find that pictures help a LOT when my eyes get tired.  Clip the limb into segments and compare the bend in each segment to the others and to the unbraced profile.  You will NOT end up with a smooth looking bend (as far as a perfect arc).  A wavy limb makes a wavy arc

Go slow, enjoy it, and learn a ton.  Ok, I'll shut up now

[Dictionary]

Sorry, off topic, but where are you from Eastman?


Work slowly on your bow.

[k-hat]

Hmmm, looking at that handle area has me kinda worried.  I see that is a spliced bow, and you're limbs don't appear to fade very much into the glued on riser.  Is the riser leather or wood?  If it's wood, you're probably going to experience the dreaded "handle popping off" problem.  You're limb thickness should increase quite a bit before the edge of the riser.  Or to say it the other way, from center, the thickness should decrease (fade) dramatically to the edge of the riser and CONTINUE to decrease past the glue line into the limb.  That keeps the handle from flexing enough to stress the glue line with the riser. 

Hope that makes sense.

[Eastman]

Thanks for all the advice guys..
The taper (in mm) currently looks like this (after working on it this morning) : measured every 3''

 15  15  16  19  19  20  21  21  22  RISER  23  20  21  21  20  19  18  17  16

Does that sound ok?

Dictionary, i'm from South Africa

k-hat, the riser is wood. The bow was spliced for me by a friend. We'll see what happens i guess..

Meanwhile, here's the bow with the 'shortened' long string as per adb's request. (4'' of tip movement) Do I now string the bow about 1''?

[Pappy]

A little form a few inches out from the fad on the left limb to about mid limb.
Then from 8 /10 inches out from the fad to the end on the right,looking ok so far.
Like has been said if you get it miving to close to the fads the handle will pop off.
   Pappy

[Eastman]

First brace. Hows it looking?