Primitive Archer
Main Discussion Area => Bows => Topic started by: grinner on September 09, 2012, 09:10:14 pm
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HI I just finished tillering my hackberry self bow it is 68" NTN and it only ended up being 37# @28 inches. I heat treated it once should i heat treat it again since i scraped of the wood. What are my other option for raising the weight 5-8 pounds? Thanks for the help
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You could pike it an inch to an 1 1/2 on each end. At 68" you probably have enough room at that draw length. That should get you close.
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Seems like you might have a little length to spare. if you pike an inch off of each tip that would gain you some weight. It would depend on the length of your handle section and fades. You want to make sure you still have enough working limb for your draw length. Otherwise you'd just be trading draw weight for set.
[[Edit: Yeah, what Kenny said. ;)]]
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yeah i thought of that I have 8 inchess non bending will piking it change my tiller? And also how much weight would that add? THanks
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Here is a formula I got somewhere. I used it once and it was pretty close.
how many inches to pike to add weight?
current length/current weight X additional pounds wanted / 5 = total inches to take off / 2 for each end.
how much weight will piking so many inches increase?
no of inches X current weight / current length X 5 = how much the weight will increase by taking 2 inches off each end.
Not sure if that is right, but it's all I have.
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Never heard of a formula to figured that out, pretty cool. Let us know if it works. I have heard, and in my experience, it's about 2#s per inch you take off.
Tattoo Dave
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I agree with Kenny. 1 1/2" off each end will get you close. Tiller should not change much if any. That leaves you with 65". Should be enough. If you scraped off the tempered wood on the belly, temper again.
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how much have you shot it, after it's shot abit it will generally lose a few more #'s, got any pic's, Bub
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Have only shot it 10 or so times and I am sorry but I dont have any pics I currently at college.
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if you can get a hundred or so arrows though it then wheigh it and see what ya got, Bub
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ok then heat treat it again and pike it a couple inches? or is the heat treating not necessary. Thanks
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Howdy, Piking the bow is the easiest, but other options exist. Flipping the tips would raise weight. A full recurve is not necessary, but still possible with the length you've got. Adding a backing? Sinew can definitely add draw weight. Planing the back and adding bamboo or hickory could raise the draw weight a lot.
Heck I've done all three ( piking, reflexed tips and sinew) and heat treating on one bow. Just don't ask why I overshot the mark quite so far.
Ron
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yeah i thought about flipping the tips but it seems very risky for a beginner like me thanks for all the good advise
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You have 3 choises.
SHORTEN OR SINEW
The third is put a been in the handle. I've did this when I really did'nt want to change the leath. I add my handles (stiff) early on after I get it cut into simi bow forms.
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I've never sinew backed a bow before but I'm pretty sure that's not the best way to go for Grinner here. First and foremost it sounds like he's a beginner and sinew backing is challenging and time consuming. Secondly, his bow is fairly long and my understanding is that the benefits of sinew are negated by the added mass on a longer bow. Sinew backing a 68" bow might make it harder to draw but it will also be making it alot bulkier. Please correct me if I'm wrong.
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If you Heat Treat the bow again you could gain 5 to 10 pounds back.
Depending on your wood's individual characteristics.
Marc St. Louis wrote a great chapter in TBB Volume 4 covering his findings in Heat Treating bows.
Where he talks about re-Heat Treating bows more than once with no ill effects.
But bear in mind he uses a laccor of sorts on the hot wood behind the advancing heat gun to combat the heat gun's tendency to dry out the wood.
I have been using Tung Oil for this purpose to good effect.
-gus
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Thanks for the help i plan on piking it this weekend and heat treating
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If you are planning to both heat treat AND pike, i would heat first, give it a couple of days to rehydrate, then check the weight and tiller before i piked it any.
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Back in the day, when I first started, a lot of my bows would come in under weight and I would do this and that to get them to raise weight. I'd pike them mainly. Came to the conclusion I wasn't learning about tillering that way. I realized I was better off just starting another bow. So that's what I did and hear I am 23 years later. I don't come in underweight too much anymore. BTW cutting an inch off each end will get you 4-5# and more set so you haven't gained anything. It may also break on you if your tiller is not good. Yes, there is a formula. It's in one of Jim Hamm's writings. Also, it's a bit on the long side for sinew. You probably won't gain any significant cast. Linen may add some weight. Not much. Anyway, have fun. Sorry to be throwing in cold rags into the discussion. Jawge
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Howdy Jawge, You have a good point, but I'm of the the "fix it 'til it's broke" persuasion. Ron
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That bow is far too long to really improve from sinewing. All you will do is add physical weight.
To make the sinew do it'd job, the bow needs to be a great deal shorter so that the sinew transfers the plane of neutrality further out toward the back. The sinew resists stretching, it gives less. So the belly has to take up more compression.
Jawge's big wet blanket was wrapped around a lot of good wisdom. If you are consistently coming in under weight, it's your tillering technique. Remove less wood in a scraping session and spend more time excercising the limbs between scraping sessions. As it's being excercised, watch how the limbs are moving. Watch for the worst of the stiff spots....then touch that section up lightly. Repeat as necessary.
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what would be the best way to add reflex while heat treating? i do not have a form could i just put something under the handle and tie the tips down? pr would this affect my tillering? thanks.
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Grinner, Look up some of the posts on heat treating. Or get a back copy of PA with an article on heat treating. I believe it's almost the rule to place the limbs in a little reflex before or during the heat treating. Your idea of a spacer under the handle would fit the bill. Ron
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Back in the day, when I first started, a lot of my bows would come in under weight and I would do this and that to get them to raise weight. I'd pike them mainly. Came to the conclusion I wasn't learning about tillering that way. I realized I was better off just starting another bow. So that's what I did and hear I am 23 years later. I don't come in underweight too much anymore. BTW cutting an inch off each end will get you 4-5# and more set so you haven't gained anything. It may also break on you if your tiller is not good. Yes, there is a formula. It's in one of Jim Hamm's writings. Also, it's a bit on the long side for sinew. You probably won't gain any significant cast. Linen may add some weight. Not much. Anyway, have fun. Sorry to be throwing in cold rags into the discussion. Jawge
Jawge is telling you the best way to do this Maybe we should listen up !
Maybe JW will help put it into better words ,but basically we need to get the rules down first before we start learning how to bend the rules !
This is a hard pill for us to swallow , but its good for us !
Stand that bow in the corner till the corner is full of them ,then we can dig one out and talk about repairs !
Have fun !!
Guy
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I use to make all of mine a couple of inches longer then I wanted just for insurance, when I got the tiller like I wanted ,I would pike it to the length I wanted and touch up the tiller, usually don't change much just adds a few pounds. :)
Pappy