Primitive Archer
Main Discussion Area => Bows => Topic started by: yellow feather on June 01, 2008, 07:12:39 pm
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My question that I was wondering is it possible to over stress the limbs over your max. draw weight, causing string follow, when you exercise the limbs after wood removal when tillering and before stringing and put on tillering tree. It seems to me that I get excessive string follow even though I never pull on the tree more than my target draw weight. David
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David, how do you keep your staves and bow blanks dry? If you live in a humid climate, chances are your wood has too much moisture content. If you have measure Rh and temp you can use the following calculator to keep the moisture down.
http://www.woodbin.com/ref/wood/emc.htm
High moisture content will cause alot of string follow.
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Sure its possible That's why you shouldn't. Make sure your bow is no more than 15 # over final target weight before you string it for the first time. Exercise at partial draw after wood removal. Jawge
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How are you exercising the Limbs.....on the Floor....like floor Tillering....or on the Tree....where you can control the Poundage Drawn???
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After wood removal. I gradually draw the bow to the draw length that I was drawing to prior to the wood removal. I do this slowly in a series of draws starting much shorter than the final draw. I then draw it further to the desired draw weight and no more.
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Sure its possible That's why you shouldn't. Make sure your bow is no more than 15 # over final target weight before you string it for the first time. Exercise at partial draw after wood removal. Jawge
Jawge, I'm guessing that you're using the long string during tillering and not bracing the bow until you've estimated the bow is about 15# heavy of desired weight?
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Sorry it took so long to get back.Thanks for all the response. I live in west Texas and for the most part, it's hot and dry with low humidity. I also try to keep it in a hot box with one light bulb. I work it like floor tillering right after wood removal before I brace it. Then I draw it some before I put on the tree.David
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You probably aren't exercising it enough just with floor tiller action. Pat
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Yep, I'm with Pat, I exercize the limbs about 30-40 pulls on the tiller tree, between wood removal, never going over draw wieght. On long string and short string. I don't do a heck of a lot of floor tillering, seems like I can see more on the tree.
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Pat, Dano.(Thanks) Today I've just been working it on the tree without the floor tillering and I have always worked it 20 or 30 times before pulling to max draw weight on the tree. I'll see what happens. Should I let the stave cool after being in the hot box before bending? David
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David, I wouldn't worry about cooling, what temp do you keep your hot box?
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Dano. I don't know how hot it is,probably 110 or so, but only has one 100 watt bulb and air space around the lid, and it's over 100 degrees outside right now. I didn't think it would hurt but thought I'd ask to be safe. David
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The only time I would worry about a bow in progress is when the humidity is up above 40%, then I would keep it in a box at about 90 deg. http://www.woodbin.com/ref/wood/emc.htm
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The only time I would worry about a bow in progress is when the humidity is up above 40%, then I would keep it in a box at about 90 deg. http://www.woodbin.com/ref/wood/emc.htm
Well that aint happening in Texas....unless it's Corpus Christi or Houston!!!!!
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The only time I would worry about a bow in progress is when the humidity is up above 40%, then I would keep it in a box at about 90 deg. http://www.woodbin.com/ref/wood/emc.htm
Ya mean humidity drops below 40 %! Well learn somethin' every day ! ;D...bob
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David, you might want to take a look at the tiller you are using with a particular design as well. A tiller can look perfect but not be right for the front view on a bow sometimes. As discussed in other threads though, a little bit of set is not such a bad thing, sometimes you can get through the tillering of the bow without much just to pick it up later when you shoot the bow in. Better to keep excersiing it and break it in as you build it. Steve
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Ya mean humidity drops below 40 %! Well learn somethin' every day ! ;D...bob
hehehe I know what you mean bob, doesnt get any better than 60 % here and thats a really dry day for us. Usually its like 80+. I dont know why, but I usually dont get anymore set than those in much drier climates. I used that site to calculate the emc and it was 15.6%...thats bad right? ;D lol even my hickory bows stay in around 1-1.5" of set.
Might need a hotbox just to see what its like.....
Alex
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Greg, there's little estimation for me when determining if a stave is ready for the short string. I long string tiller out to 10 inches all the while checking weight. When the stave shows target weight or 5# over and the limbs are bending well then I string the stave for the first time. When I exercise the stave after wood removal I do t at partial draw just to stress the wood a bit. Jawge
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is this 10 inches total limb travel, or just simply string travel. i.e. like putting on a tight stringand pulling it a total of ten inches, or just how far the tips move. i have been kinda fuzzy on when exatcly to move to a short string.
Phil
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I put the short string on as soon as I can, because in the past i've tillered bows out using the long string only to find them sadly underweight. Adb uses this definition of a long string: just long enough to be taut when attached to the nocks, without bending the bow or hanging loose. I started to do this, and found that my bows are more consistent to what i want them to be, after that. Once you can draw a bow to desired weight at, say, 15" of draw using adb's long string, then string it to a very low brace height (say, 2 inches). Keep on tillering and drawing the bow, increasing brace height in 1" increments as often as you can without damaging the stave. This takes a little practice. By doing it this way, you'll be at full brace height of 7" or so before you know it, and your bow will pull the weight that you require. Best to tiller in a few pounds over desired weight, so you can round over the edges and do final sand without coming in underweight.
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ok i understand. what ive been doing is tillering down till the limb tips get to a distance marked out on my tree. this mark is at a 7" brace height (from the back). then going on as you stated. thanks
Phil
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Dano or whoever.
If the humidity is 55% and you have had the wood in a hot box(hickory) over night, how long would your estimate be as to how long would the mc stay low enough to work on the tiller? David
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Just over night won't dry it enough, I would wait a few days, but after that you can work the stave for a session put it back in the box and so on, till it's ready for finish.
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Just over night won't dry it enough, I would wait a few days, but after that you can work the stave for a session put it back in the box and so on, till it's ready for finish.
Sounds like a Lot of wok....just send it to Me ....here in the Texas Panhandle....the Humidity stays around 6-10 percent....and I will make good use of your Stave........ Without the Hotbox !!!
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Destructo
Yellow feather is my brother and he started on this bow about 5 months ago.
I keep tellin him he's afraid to finish it :D It is his first unbacked stave bow and he's pretty close to getting it to weight.
I told him he needs an alarm that goes off when the humidity drops below 40% so he can work on it.
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Thats funny!! I was really leery on My first Stave Bow too....I was all Fine with a Board...but that first Piece of Natural Wood with all of it waves and dips...and other flaws...just overwhelmed Me for the first one...but once you get the first one under Your Belt....it's all Fun again!!!