This is my second attempt at a hickory selfbow. The first developed a lot of string follow and eventually broke at a knot in the limb. I've got the bow to begin bending and the upper limb which appears straight when unstressed goes into a twist when bending. I have worked a couple hours trying to get it out by working the heavy side of the limb down but its not coming out.
(http://i55.photobucket.com/albums/g144/spencsj/IMG_0665.jpg)
Below is the upper limb with twist
(http://i55.photobucket.com/albums/g144/spencsj/IMG_0666.jpg)
Below is the lower limb with slight twist in opposite direction.
(http://i55.photobucket.com/albums/g144/spencsj/IMG_0667.jpg)
Do I worry about this twist or ignore it and just working on achieving even tiller while working both limbs down? Thanks in advance for some helpful advise!
Don't worry so much about the twist. You can correct it after you tiller. But make sure your limbs are the same thickness on both sides of each limb. That's probably the culprit. Catch that left limb up with the right. Tiller sticks and pulling the bow too far too soon will cause set. Pulley style tiller trees are a better option. Have fun, looking good so far.
I agree with John about the tiller stick. I done my first bow with a stick. Then I built me a pulley style tree and I really like it. I did incorporate holes with a peg so that I can hold and back off to take a look at the tiller but I only leave it pulled for as little time as possible and very rarely even do that. Most times it's to take a pic.
I agree with john about the limb thickness. I work mostly with Hickory and find it pretty consitant usally its me. I start at the center of the bow making marks every 2 inches then check the thickness and each side at each mark and can usally find my thick spot or spots. I am not the best the eyeballing thinks so I measure alot.
Thanks all - I will check it and continue working it.
I built a hickory bow a little while back that had a slight twist in one limb, it eventually shot out on its own, about 300-400 shots. Your twist is a little more severe than mine was however. I second the pulley style tiller tree. You dont have to hold the bow at draw for as long. Its looking pretty good so far, you have a lot of material and time left to get it going in the right direction.
a twist like that can happen when rasping if u are right handed. The left side gets more removal and bow limbs propeller.
I'd feel the limbs...your fingers will tell if the limbs are not the same thickness across the width
Ok - so I slowly caught the left limb up with the right - or so I thought. My eye said it was pretty even but I was having trouble knowing for sure because of the twist. I got the bow to a point where I could brace the bow. Once braced, I can really see where it is out now. I recall seeing photos of someone tillering the bow while it was braced. Is this a good idea. I still have plenty of wood (at least I think) to bring it back to good final tiller. What is the best method when you get to this point?
Have you checked the weight. If not, don't string it yet.
Not to hijack the thread, but my red oak bow developed a twist in the bottom limb too midway through tillering. Wondering if the tillering stick caused that too.
John - can you expound on that a bit? No I have not checked the weight but I know its more than I want to end up with. I don't really have a target weight in mind - more concerned with getting a well tillered bow. If it comes in somewhere around 50lbs - that would be a bonus.
You really shouldn't be bending it without knowing about how heavy it is. Never bend it too far when it is too heavy. And never brace it until it is about 10# below your target weight at about 16-20". That's what causes set.
Also, a certain design, ie. length width, style, is better for a certain weight. Start with your draw length and you will determine your draw length. Then your draw weight and that will determine the width.
John,
Good info to know. I'm not sure I have seen that elsewhere. 10# under @ 16-20". Thanks
Staves don't really develop twist. They were either there before tillering started or were caused by uneven wood removal. If they aren't to bad and already there: I usually leave them. If I caused them I remove wood from the high side. ) Jawge
That's just how I explain it. The way I figure is that this method gives you plenty of weight to work with for tillering but doesn't overstress the bow. As you gain experience you will get your initial dimensions closer to final dimensions before tillering. For now, this is close enough.
There are many paths to the promised land where target weight and target draw meet. It is common practice to not pull past target weight. But if you are pulling target weight at 10", you are unneccessarily overstressing the bow. Overstressing causes set.
Ideally, we would know exactly what our final dimensions are and get the bow to them before we ever pulled it. That's not possible with wooden bows so we get as close as we can before bending.
OK, so how do y'all use the tilering gizmo with a pulley system? Seems for a newbie, using a tillering stick so you can use the gizmo, would offset the negative of some set. I'll be tillering mine this weekend, which is why I ask.
QuoteOriginally posted by George Tsoukalas:
... If I caused them I remove wood from the high side. ) Jawge
OK, I've heard this before but am not sure I understand.
What is the 'high' side? Does that mean it's more toward the back or more toward the belly?
Do you remove the wood from that side of the belly or actually from the side of the bow?
Thanks guys!
CJ
John, so are you saying to get 10# short of target 16-20" on a short tillering string before bracing? Just wondering how you suggest measuring the 16-20"... Thanks.