Author Topic: Tillering problems. I really think its the wood's fault, not the bowyer.  (Read 12649 times)

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Offline Goose Fletch

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Hi everyone

I just started tillering a warbow. It measures 7' and my projected weight is 80# at 28 or 100# at 32".

The issue is that one limb is excessively stiff while the appears to be responding to scraping and filing. The stiff limb is showing little improvement and im not sure if its me or the wood. I try to scrape both sides and the belly equally on this hickory board warbow. Any one have any suggestions?


Offline Newindian

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Keep scraping. I'd say Work on the right inner two thirds. Is this your first?
I like free stuff.

Offline WillS

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If I may offer some info I've picked up recently while making the same mistake - forget being even at this stage.  If the wood is denser on one limb, you'll need less wood on that limb.  It really is that simple.  You might end up with one limb being a good few mm thinner than the other, but if that means both limbs are working the same, and the bow is balanced you've done your job.  Be aware of it getting TOO thin of course, but there's nothing wrong with the limbs being different thicknesses up to a point.

Is the stiff limb reflexed at all? If it is, you'll need to keep it stiffer in relation to the other because that's what the stave will want to do, but if both limbs are straight then basically keep working the stiff limb down until it balances out.  Make sure you're really exercising the bow as you work - often it takes a while for the changes to become obvious and they can suddenly show up at once causing a hinge.

Let somebody with more experience guide you through this but this is stuff I've been told and hopefully some of it helps a bit!

Offline Goose Fletch

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New Indian, thanks for the advice, this is my 4th bow now. but ive been lurking here forever haha

Will, if I balance it, I  think I will have an unusually thin limb. I assume that if both limbs match in shape, then they should in theory match in weight, which supports what you are telling me. however, will this have unwelcome performance characteristics? wouldnt one limb be heavier in mass? after examining the growth rings on both ends, it looks like the stiffer limb has thicker latewood rings.

the blank had about 1 inch of reflex which i had tried to induce by leaving the hickory in a perry reflex for a little while, allowing time and ambient moisture to do its thing. this has been reduced to a little over 1/2" at the moment.

what about the handle area? i was hoping for a full compass tiller. do you think the bow will need more work done near the waves?

Offline toomanyknots

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You just gotta bring the stiff limb along to meet the weaker limb is all. Just keep scraping. If the limb is getting thin, it is still better to have a well tillered bow with an oval / funky cross section than a bad tillered bow with an even cross section. My advice is to just worry about the tiller for now, don't worry about it being thin or thick, etc. Looking like a good bend on the left limb though, now to bring that right limb along,  ;D.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Goose Fletch

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Haha thanks. I suppose patience does help as well.

Here is the most recent tillering check. The stiff limb is becoming increasingly thin, its a little frightening, still not sure where to remove wood now.

Offline DarkSoul

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Is the bow braced to a full brace height? It should be, by now. What weight are you drawing it to, in the last picture? The tiller looks pretty good, but the right limb is just stiffer than the left limb. I'd scrape the full length of the right limb with a scraper for three minutes and check again. Make sure to exercise the limbs at least thirty times after each tiller correction is made.
"Sonuit contento nervus ab arcu."
Ovid, Metamorphoses VI-286

Offline toomanyknots

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72" is pretty short for 100 @ 32 in most cases anyway, so I would just pike the weaker limb and just let the bow come out however it wants to come out. That would get your tiller to come around, you might have to lob off a good couple inches though. I wouldn't brace it till it looks even, just me.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Goose Fletch

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Is the bow braced to a full brace height? It should be, by now. What weight are you drawing it to, in the last picture?...

Thanks, and yes, it is braced to full height at the moment. It pulls to about 75# right now. Just gotta keep scraping and exercising but I am planning to pike it as well. Its pretty long right now.

Knots, I agree with you, 72" is too short. thankfully its 84" long haha ;)  (sorry for not indicating its length in inches, I just lazily wrote 7 feet in the original post). If I pike it, would I need to grip it in the center of the new length or should I hold the bow where I used to hold it before piking?

Offline Del the cat

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Have a look at this post from my blog, it shows how you can experiment with piking a limb by different ammounts without taking off any wood!
I had exactly the same 'weak limb' problem.
http://bowyersdiary.blogspot.co.uk/2014/03/drat-lost-some-weight.html
Del
« Last Edit: May 29, 2014, 04:21:30 am by Del the cat »
Health warning, these posts may contain traces of nut.

Offline toomanyknots

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Is the bow braced to a full brace height? It should be, by now. What weight are you drawing it to, in the last picture?...

Thanks, and yes, it is braced to full height at the moment. It pulls to about 75# right now. Just gotta keep scraping and exercising but I am planning to pike it as well. Its pretty long right now.

Knots, I agree with you, 72" is too short. thankfully its 84" long haha ;)  (sorry for not indicating its length in inches, I just lazily wrote 7 feet in the original post). If I pike it, would I need to grip it in the center of the new length or should I hold the bow where I used to hold it before piking?

LOL sorry, my mistake! I'm about retarded,  ;D. (No idea where I got 72") Yeah, you got plenty of length to pike the weaker limb! I'd go about an inch at a time until the tiller looks even and then see what weight I was working with.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Badger

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     Was the bow stored in such a way that you are confident that the moisture is equal on both sides of the bow. I used to store all my bows in a big drum and the bottom limbs were always showing weaker after setting in the drum for some time.

Offline Goose Fletch

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Have a look at this post from my blog, it shows how you can experiment with piking a limb by different ammounts without taking off any wood!
I had exactly the same 'wak limb' problem.
http://bowyersdiary.blogspot.co.uk/2014/03/drat-lost-some-weight.html
Del

Haha thanks del, I know exactly what you mean when you say you've had a belly full of belly. Brilliant idea, i don't know how you come up with these.

Is the bow braced to a full brace height? It should be, by now. What weight are you drawing it to, in the last picture?...

Thanks, and yes, it is braced to full height at the moment. It pulls to about 75# right now. Just gotta keep scraping and exercising but I am planning to pike it as well. Its pretty long right now.

Knots, I agree with you, 72" is too short. thankfully its 84" long haha ;)  (sorry for not indicating its length in inches, I just lazily wrote 7 feet in the original post). If I pike it, would I need to grip it in the center of the new length or should I hold the bow where I used to hold it before piking?

LOL sorry, my mistake! I'm about retarded,  ;D. (No idea where I got 72") Yeah, you got plenty of length to pike the weaker limb! I'd go about an inch at a time until the tiller looks even and then see what weight I was working with.

Not at all man. Thanks, I'll give it a go and try it out tomorrow. I really want to get this bow overwith. Its been agonisingly unresponsive. Unfortunately i have 2 more blanks just like it. Maybe I'll splice and match them, though i doubt it will yield the kinda bows we like in this thread.

     Was the bow stored in such a way that you are confident that the moisture is equal on both sides of the bow. I used to store all my bows in a big drum and the bottom limbs were always showing weaker after setting in the drum for some time.

Unfortunately i have no way of knowing, except that it was kiln dried. Since it was purchased, its been stored indoors and we are just recovering from a very dreadful winter. So no ambient moisture to be worried about. Never thought about moisture, but i will be attempting to heat treat this bow as well. Btw, im planning to use the mass formula you sent me a little while ago!

Offline WillS

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Don't forget you do want one limb stiffer than the other at the end.  The bottom limb should be slightly stiff because of the way it's actually shot as compared to how it's held on a tiller.

Are you pulling the string from the middle and supporting the bow in the middle? If you are, leave one limb stiff and draw the bow in front of a mirror (or get somebody to draw it while you watch) and you'll be surprised how different it looks.  It will come round nicely in the hand if it's slightly stiff now. 

If you've accounted for this, and you're pulling the string say an inch above center and supporting the bow slightly below center then you do want to be going for an even bend on the tiller tree, but it's still incredibly hard to emulate a real draw on a tiller.

It.probably isn't the woods "fault" per se - all wood is different and as a result it all throws up different challenges every time.  There's no such thing as a perfect stave - the next one might not have as obvious density issues, but instead might have grain run out, hidden rot, knots, pins, spalting, twist, deflex..... And so on.  You just gotta go with it each time and beat it.  For what it's worth though, there's no reason not to splice your next one - a few really talented bowyers have made super heavy warbows (160# plus) that bend full compass despite being spliced. 

Offline Goose Fletch

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Don't forget you do want one limb stiffer than the other at the end.  The bottom limb should be slightly stiff because of the way it's actually shot as compared to how it's held on a tiller.

Are you pulling the string from the middle and supporting the bow in the middle? If you are, leave one limb stiff and draw the bow in front of a mirror (or get somebody to draw it while you watch) and you'll be surprised how different it looks.  It will come round nicely in the hand if it's slightly stiff now. 

If you've accounted for this, and you're pulling the string say an inch above center and supporting the bow slightly below center then you do want to be going for an even bend on the tiller tree, but it's still incredibly hard to emulate a real draw on a tiller.

It.probably isn't the woods "fault" per se - all wood is different and as a result it all throws up different challenges every time.  There's no such thing as a perfect stave - the next one might not have as obvious density issues, but instead might have grain run out, hidden rot, knots, pins, spalting, twist, deflex..... And so on.  You just gotta go with it each time and beat it.  For what it's worth though, there's no reason not to splice your next one - a few really talented bowyers have made super heavy warbows (160# plus) that bend full compass despite being spliced.

no problem, I have learned about intentionally stiffening the bottom limb here. actually. and yes, pulling the bow and the string from the middle. YEAH! it absolutely looks different in someone else's hands, in this case, my much larger younger brother. haha.I see, thanks for sharing, until now I thought a tree tiller replicates the human drawing the bow.

yeah yeah i know :( :( its never actually really the woods fault. really? 160# despite being spliced? do you have any links by some chance? i'll look around on this forum as well. thanks for the help Will.

i just cut an inch off the bottom and suddenly the bow looks great. still underweight but i will probably continue pruning it.