Primitive Archer
Main Discussion Area => Bows => Topic started by: Eastman on November 29, 2012, 11:35:17 am
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Good day all,
The exams are all over,it's summer vacation and I have time to make bows again! ;D
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)
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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.. :)
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That blesbuk looks to have lots of good bow-making parts on em ;D I cant see anything wrong with that initial bend.
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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
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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.
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You chose a challenging stave. it really isn't bending enough to tell anything. Jawge
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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.
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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.
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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
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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 ;D
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 ::)
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Sorry, off topic, but where are you from Eastman?
Work slowly on your bow.
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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.
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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''?
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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
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First brace. Hows it looking?
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Drawing it the first few inches
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Right limb still very flat from fad to mid limb. It does seem to have some natural reflex in that limb so it may be slower coming around,go slow,few scrapes at a time till you get it moving. :) Also be careful on the left at the fad,don't take anymore till you get the rest of the limb moving,can hinge there pretty easy. :)
Pappy
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Thanks for all the advice, I really need it :)
Braced 3'', drawing it 10''
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I'm completely leaving that hingy spot alone. Just slowly removing wood from the rest of the limb.
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Left limb fad to mid limb,right limb mid limb to tip. Are you putting it on the tree the same each time ? Looks like you have swapped sides,I always put it on the tree the same each time so I can keep up with what I am doing.
Pappy
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I removed the wood like Pappy said and slowly kept going. :) Here it is at 14''. The right limb looks like it's got a hinge, but when you look at the bow unstrung it's just a kink. Or am I wrong?
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Here it is drawing about 40# @22''. Tiller looking ok?
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Right limb needs to bend more from center to tip. I'd probably flip the bow around and pull it looking at the other side of the limbs just to be sure of what I was seeing on this side.
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I don't see any hinge. :) What Steve said on the right limb,looking good so far. ;)
Pappy
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By friday afternoon I had it up to 45# @25'' :D. I was away for the weekend so I couldn't do any further work.
Tomorrow I plan on sanding and cleaning up the bow, then slooowwly start shooting it in and tweaking the tiller if necessary. By then it will be about 45lbs at 28'' I hope.
Does this procedure sound OK? I really appreciate all the help and advice :)
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Here's some pics of the bow after some sanding. Drawing 45# @26''.
The limb with the deflexed tip on the left and on the next pic it's on the right. The limbs do have slight propeller twist. So the limbs appear to bend kinda differently in the pics.
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They are not perfect but I don't see any real dangers. I'd have to see the limbs up close to see where possible stiff areas would be and figure that into the tiller picture.
To answer your question, yes, it is a good plan. And not to confuse the issue but, personally, I don't use my tree to full draw extent. I use the tiller stick up to 16" of draw then I go to the tree for 20+ inches then I pull in front of a mirror beyond that. Thats just me and there are other ways to do it. You can and will get different tiller pictures if you pull the string from where the arrow will be.
So if I were you I would take the bow down and pull it in front of a mirror and compare that to the tiller tree picture. If they are very similar then, by all means, stick with the tree to full draw. Otherwise, you might want to tweak tiller via the mirror.
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Looks like the left limb is bending a little much a few inches from the fad to mid limb,that could be the twist,flip it around and see how it looks, also like steve said I like to draw them by hand when I get out close to full draw and see how they look,sometimes you will be suprised at how good or bad they look,but is usually different. :)
Pappy
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drawn to 24'',
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Hard to see with the pictures side ways but looks like the top needs to bend from fad to mid limb and the bottom from mid out to about 6 inches from the tip. Not looking to bad at all. :)
Pappy
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Ditto Steve. I only use the tiller stick for about 16 inches. I would get the limbs bending as close to perfect at that length as possible before I started shooting it or even bending it much farther. You've got some spots that need a little attention before proceeding. Don't rush it at this point. Common desire for everyone, especially new bow makers. Get it right, then go another inch or two. Your bow is at the point where your patience and attention to detail, or lack there-of, will determine the outcome.
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After a little more sanding on stiff spots here it is again at more or less 43# @26''.
The first pic below shows all the character before tillering started, just to comapre to the bow when drawn. It may not be perfect, but any other pointers? Thanks
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I'm no expert, but I think it's coming along nice. Bends look good to my untrained eye. Kind of fun seeing the progress through tillering step by step.
-Dan
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Looking good,maybe a little more on the fad on the left limb. You about got it. :)
Pappy
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This will probably be my last post for the year. The bow is coming along fine ;D As soon as I get the bow finished I'll post it early next year. Heading to the coast tomorrow, so if I can I'll post one last draw pic.
Thanks for all the much-needed advice, I really appreciate it. An early Merry Christmas to you all. :)
P.S.
The bow's name just 'popped' into my head in the way that they sometimes do. "Grace"