For discussion: how this bow should be tillered (Updated with full draw pics)

[druid]

Last year I have found sapling of tree of heaven. I didn't know its qualities, it is new wood for me so I made some testings. Sapling had almost 3" of reflex but very ugly positioned: in two spots on middle of the limbs. Also it was snaky. Because I didn't know its compression and tension abilities I was carefully. My question is: how this bow should be tillered? Here is just side profile pic. It has 1 3/8 " wide limbs to the half of length and tapering to the nocks, 68 ntn. I want to hear all, there are no stupid answers- we are all equal. Here you are friends, pic after loosing 1" of reflex during tillering...

[Del the cat]

IMO, if you don't know the properties of the wood then you need to play it safe by keeping maximum width and tillering by removing from the belly (maybe decrown if necessary to avoid losing width) Tiller it to an arc of a circle shape with every bit of the limb working.
Mind I dunno why you are asking as your bows are always superbly tillered.
Del

[Badger]

     Being a sapling I would assume the wood has a crown, if this is in fact the case I would get the wood bending through the handle a bit and gently increase the rate of bend until I reached the point where the bow starts to taper, at that point I would gently start reducing the rate of bend. Once I had the bow bending nicely I would check the mass weight of the bow and from that point decide how much draw weight the bow could handle. ( assuming the wood is dry) Steve

[johnston]

druid I feel silly giving you advice but an opinion, well that's different.

One and 3/8" ain't wide so I would use as much of the 68" as possible including the handle. In other words I agree with Del, arc of a circle D bow.

Lane

[bubby]

i've gotta stave of this ruffed out, it's a med. density hard wood, takes heat good, a guy built one on here a ways back, i'll see if I can find the post, Bub

[druid]

Del and johnston, are you sure this stave can be completely circular (or even close to that)?  Wouldn't it break the rules about following the shape of the stave?
Steve, like always- your advice is good but I was in dilemma about this stave- where to bend (and where not) exactly. It is just about 100 greins different from your mass formula now. Long time ago I haven't such problematic stave.

[Badger]

 Druid, you may want to opt for a lower weight if it starts to show signs of set.

[druid]

Steve, now, in this moment it is recently finished bow. It is exactly 150 greins lighter than resulted in your formula. Have about 1 1/2 reflex and a lot of early draw weight. It seems faster than average bow of that dimensions I usually made. It is tillered following all good mantras, to see what will happen, how it will look like. It is 50# 30". I wanted to hear some more opinions about shape of the tiller and bend positions. Tommorow I hope to make all the pics and post finished bow and explain my desicion of shape. This is not reason for others to stop discussing this question, OK?

[Del the cat]

I mean and arc of a circle averaged out over the wiggles.
Gotta admit it can be a nightmare... you think there's a hinge starting, then you realise it's just a spot of natural deflex.
But hey it's more fun than starting off with a load of f/glass and machined lams.
Del

[artcher1]

Braced profile should be elliptical to reflect the limb design that you chose for your rectangular shaped limbs. Semi-gull wing braced profile. Handle should begin to work as you near full draw. Mid-limb stiffened to dampen limb vibrations. A nice fast design IMO. Whether it'll hold it's present shape is another matter at that limb width. Haven't used that type wood either.......Art

[johnston]

Mind now, I don't know much.

The D shape I said earlier applies only to the part of the bow that is actually bending including the handle.
 Your outer limbs may wind up with little or no bend after the reflex and act like a static lever. Looking
at the ONE pic it appears that you have about 14" after the reflex to each tip. That would give you 40" of
 working limbs if the handle was bendy and the shape would be a D. Just my opinion from looking at the ONE
pic.

Lane

[bubby]

druid, Nathan Elliot built some of these, said it resembled ash, i think the bow he posted was a mollegabet, Bub

[druid]

We spoke about this bow. As I sad it was very difficult for me to tiller it corectly, to have equal strain allover the limbs. Almost 3" of reflex in almost just two spots in the limbs....Also some snakyness. I was trying to follow all good manthras. In the middle of the bow there was a little reflex spot. So, what I have done: Because of its reflex, middle on the full draw should look stiff. Ok, done. Limbs to the reflex spots should bend normaly- done. But what now....reflex spots should look stiff on the full draw because of its reflex- one more than the other, it's reflex must be visible even on the full draw. What about limbs after that reflex spot?! If I make them bendible it will affect string angle very much...I deicided to keep them stiff but light. How then to achieve full draw lenght, I need more space? The only thing I could- sacrifice inner limbs and force them to bend more. When I finished this I recheck bow- still have 1 1/2 of reflex (lost one inch in the critical reflexed spots), so it is not overstrained. Badgers mass formula also confirm that its physical weight is almost correct (467 grams is formula and bow is 410 grams). I tried it on the target- very good, seems above average speed (hard and for me to believe). Because it is centershot (there must be some little torq but I do not feel it) the brace is low, just hair above 4" so arrow do not have to avoid handle a lot and gain some speed beacuse further travelling with string, to pick up some more speed that was lost with more bendible inner limb. One correction: bow is 55# at 30", my apologie, must be too much beer on weighing before. But when I looked it on the full draw- it is awfull. What to say....ugly but works very well. This was just an experiment how bows could be made even from worthless staves if you follow instructions from excellent master-bowyers from TTBB. Thank them.

[gstoneberg]

Druid, I don't think the full draw is awful at all.  Based on the unstrung and braced pics, you have 1 normal limb and one reflex limb.  Consequently you have a limb that bends as a traditional longbow and one that bends like a D/R laminate.  Since I'm a little OCD I would have probably taken that reflex out with heat to make it easier to tiller.  You did it the hard way and it looks fine to me.  Good work, your tillering skills are impressive.

George

[johnston]

How you made such a beautiful weapon out of that piece of wood is beyond my understanding. Oh I know what you did and understand why
but like George said , the heat gun would have been my option. That is a beautiful background for the pics by the way.

Can you become a master by studying the masters?

Lane