Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on February 21, 2017, 08:20:21 pm
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Is it normal that the tips will be bent more after you change from a long string to low brace?
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Not sure, but I can say that I'm always surprised how different the bend looks at a low brace than it did on the tree with a long string.
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I always notice a change as well. That's why I go to a short brace as soon as possible.
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Yes. Outer limbs bend more with the proper length string than with a long tillering string.
Tillering string's shouldn't be much longer than the bow to minimize these effects.
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I did not know this I don't use a very long string anyways no reason in particular.
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If I use a gizmo I like to use it on the long string because it comes out more elliptical once I switch to the short string.
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The longer the string the more straight down it pulls the limbs. Once braced the limbs are pulled inward. I can't explain it but there is a difference that I found in what the bow tells you in each situation. I use a long string only until I can low brace(8" to 10" of tip movement). To me long string tillering is just an extension of floor tillering. I adjust the limb bends in each section of the process so when I get to regular brace height both limbs are bending even and together or at least pretty close. After that it just loosing weight with a little limb adjustment.
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The tips of a finished bow do not move that much...maybe a few inches...at least for my bows.
Same with a long string. I long string only to 10 inches of string movement.
Jawge
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The longer the string the more straight down it pulls the limbs. Once braced the limbs are pulled inward. I can't explain it but there is a difference that I found in what the bow tells you in each situation. I use a long string only until I can low brace(8" to 10" of tip movement). To me long string tillering is just an extension of floor tillering. I adjust the limb bends in each section of the process so when I get to regular brace height both limbs are bending even and together or at least pretty close. After that it just loosing weight with a little limb adjustment.
Pat, that sounds like quite a bit of tip travel before you low brace, but I am hoping to learn more about how to get my bows closer to finished dimension before bracing, would you be kind enough to pass along how much of your design weight you like it pulling on the long string (at 8-10 tip travel)? I presume that you also use as short a longstring as possible?
thanks
willlie
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Yes it is normal.
Expect slightly more bend from mid limb out.
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Does this mean that outer limbs bend less with a lower brace height?
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The longer the string the more straight down it pulls the limbs. Once braced the limbs are pulled inward. I can't explain it but there is a difference that I found in what the bow tells you in each situation. I use a long string only until I can low brace(8" to 10" of tip movement). To me long string tillering is just an extension of floor tillering. I adjust the limb bends in each section of the process so when I get to regular brace height both limbs are bending even and together or at least pretty close. After that it just loosing weight with a little limb adjustment.
Pat, that sounds like quite a bit of tip travel before you low brace, but I am hoping to learn more about how to get my bows closer to finished dimension before bracing, would you be kind enough to pass along how much of your design weight you like it pulling on the long string (at 8-10 tip travel)? I presume that you also use as short a longstring as possible?
thanks
willlie
Willie, if a bow is on a long string or braced they will still read very similar pounds of draw weight at the same inches even though the tip movement is much less on a long string. Very often on highly relfexed bows I will keep them on a long string much longer than a more moderate design. I usually brace on these types of bows when I am hitting target weight at about 24" on a long string. It will read very close to the same thing once braced.
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Willie, I look for good limb movement. I long string tiller out to 10 inches. I keep checking weight never forcing the stave to bend. I try not to pull beyond target weight more than 5 lbs.
When I get target weight or a little over at 10 inches, I string it with the short string at a low brace.
That puts me at around 10# over target weight.
Stringing a bow that is too heavy can be problematic.
There's more on my site. Check the buildalongs.
Jawge
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Thanks guys, it's nice to notice something and be right for a change. I first noticed this when I was tillering and almost perfect yew stave It was going so smoothly and nice on the long string and I was enjoying working it so much that I was at almost full draw and still on the long string. I very quickly braced it and noticed that it was a little whip tillered. I still had enough to go to save it so it all worked out.
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Would you guys say its best to concentrate mostly on tillering the inner half of the limbs mostly while using the long string, until its ready for brace, then work on the whole limbs after brace?
Also, has anyone come up with a device or method that could crank a long string down from long to short while its on the bow?
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It's not a big effect(that I've noticed) so I wouldn't sweat it, just so you know it happens. On the bow I just mentioned I was out to 23-24" before I noticed I was still on the long string and I still managed to bring it around. You could possibly use a turnbuckle in your string but it's just more shrapnel. Del uses a washer(I copied him) and just loops the string threough it to get it a s short as possible but you can't change the length while it's under tension.
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Willie, by the time I get 6" to 8" of tip movement and everything looks good I am at a point that I can brace the bow. This is usually about 10# or so over my final draw weight. If low brace looks good I go to regular brace height and continue on with final tillering. Generally at this point all I'm doing is reducing draw weight.
txdm, I try to be sure both limbs are bending even and together, not just the inner limb. I generally save the inner most part of the limb until last and then bring the bend back into the fades. I like my limbs to bend right up to the handle and I like to feel the handle area give just a bit as I hit full draw.
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I was surfing through the Archives and found a picture of Marc's Bracing Board. It is a 2x8 with a few holes for pegs drilled in it. It looked like the deal for arthritic old guys. I was just wondering if you put the pegs in the final position you wanted or if you started on the low pegs and worked your way up.
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I have never used a bracing board, ,,but sounds like a great idea for reflexed bows,, Im gonna check that out, :)
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Picture is worth a bunch of words
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Willie, by the time I get 6" to 8" of tip movement and everything looks good I am at a point that I can brace the bow.
Thanks Pat B
If it seems like I ask this question a lot, well, it's because I do. I have been curious about just how close to finished weight different guys floor tiller or longstring before bracing. As an experiment, I tillered my last bow such that half the desired finished draw weight gave a tip deflection of 6". With the bow then braced, and without any further adjustments to tiller, full weight brought the bow to 25" draw. I will admit that doing this does not leave much room for any final adjustments, but I feel that having never pulled enough to create damage during tillering has something to do with getting the best string tension at brace of any bow I have made yet.
One thing that I must mention is that I use as short of a longstring as possible, as tight as I can tie it, without bending the bow. This actually gives more tip deflection than the same weight on a longstring with droop. I just went back to the tree to verify this difference, and found when working with a the bow cited above, and using a longstring with with 16" of droop, that 40% more weight is needed to get the same deflection, at least on the finished bow.
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I don't leave the floor until its safe to brace it with at least a 1-3" brace. Otherwise everything I see on a long string is pretty much false, that's my way of doing.
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but I feel that having never pulled enough to create damage during tillering has something to do with getting the best string tension at brace of any bow I have made yet.
I've seen this sentiment quite a bit on here lately(I'm not pickin' on ya Willie)
Does this mean that "exercising" the bow on the tiller tree is not such a good idea or does "never pulled enough to create damage" just refer to don't pull over the draw weight?
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well I would venture to say that exercising before the bend is as even as possible, could be detrimental. there is that non-visible kind of compaction that happens before it shows as set.
I am hoping that others with more experience will comment. I will have to shoot the bow a couple of thousand shots and see what has changed, to be sure myself
I never hold very long, and a fresh piece of wood will last longer if treated nicely, and everything wears out eventually.
I do suspect that giving a stave a hard pull on a long longstring or floortiller may overstress the center portions of a bow in progress.
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Willie, by the time I get 6" to 8" of tip movement and everything looks good I am at a point that I can brace the bow.
Thanks Pat B
If it seems like I ask this question a lot, well, it's because I do. I have been curious about just how close to finished weight different guys floor tiller or longstring before bracing. As an experiment, I tillered my last bow such that half the desired finished draw weight gave a tip deflection of 6". With the bow then braced, and without any further adjustments to tiller, full weight brought the bow to 25" draw. I will admit that doing this does not leave much room for any final adjustments, but I feel that having never pulled enough to create damage during tillering has something to do with getting the best string tension at brace of any bow I have made yet.
One thing that I must mention is that I use as short of a longstring as possible, as tight as I can tie it, without bending the bow. This actually gives more tip deflection than the same weight on a longstring with droop. I just went back to the tree to verify this difference, and found when working with a the bow cited above, and using a longstring with with 16" of droop, that 40% more weight is needed to get the same deflection, at least on the finished bow.
Knowing the type of wood your using helps a bunch with floor tillering to short string even tiller within 5#'s of draw weight.Right width/length etc.Not knowing will lead to an underweight bow a lot of times too.Taking your time during these stages and keeping the wood inside dry helps a lot too.Making a fine bow.In the end the bow will have to do it's job.Shooting many arrows and long brace times.
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Long string tillering is just another step in the process. Floor tiller first, then long string, then low brace, then full brace, then work out to full draw. The sooner in the process you get both limbs bending evenly and together the easier the tillering process becomes. I never pull past ultimate draw weight but I exercise from early on and every time I remove wood.
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So far, my biggest mistake was seeing the stiff outer limbs on the long string and tillering until they curved nicely... When put on the brace string they went too far and it took a set, of course. doh!
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dxdm, how far did you long string tiller? Jawge
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So far, my biggest mistake was seeing the stiff outer limbs on the long string and tillering until they curved nicely... When put on the brace string they went too far and it took a set, of course. doh!
txdm...And you don't want the bow to look like a braced bow totally on the long string.Just so they bend evenly still looking a little stiff in the outer limbs.Refer to what Mike said.Suppose you found that out now as you say.Good floor tillering will reveal the true bend of your limb more so than the long string.Since pressure is applied to the limb the same way more so like being drawn than on the long string.
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the last bow I made had alot of reflex,,
I could not go from floor to low brace,, and hit my weight,, just not strong enough to get it strung,,
I had to tie nocks below the cut in nocks and pull it with a long string to get it strung,,
(hadnt discoverd the bracing board)
so I pulled it with my make shift stringer and got is low braced and lt looked pretty even,,
I think the main reason it was close,,, is experience,, I have made so many bows that that I got the taper even enough that it braced up pretty nice,, sometimes that is the formula , lots of experience,,,, and hard to put into words or draw a picture,, on the more challening bows,, you just gonna get better with more experience, and its slow coming but you will get there,, :)
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dxdm, how far did you long string tiller? Jawge
Just long enough to put on the nocks without any slack... I just got carried away. Fortunately I was able to use heat to take it from 2" set down to 1", and it has stayed that way so far. (Hickory board bow)
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Good floor tillering will reveal the true bend of your limb more so than the long string.Since pressure is applied to the limb the same way more so like being drawn than on the long string.
Interesting technique, Beadman. Do you push downward with one hand while pushing sideways with the other?
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sounds like I'll try first floor tillering then something like a 3" brace. would the limbs be stressed practically the same proportion between 3" and 6" brace? (ie not more significant outer limb bend with 6"?)
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willie...I'm really not pushing sideways.It's the same technique shown in TBB books.No secret technique.There's pictures in there.Doing one limb at a time.Just takes practice.I used an old FG bow that was 40#'s to practice with before I made my first self bow.To get the feel of it.
Off of my right side.Bows belly kinda facing me.I'm right handed.My left hand grabs the upper limb.My right hand pushes at the handle with the tip against the ground.I look down the side of the limb to see the bend.My right hand remembers the pressure it took to get the limb bending a certain distance.I turn the bow around.Off of my left side my right hand grabs the upper limb.My left hand pushes at the handle with the tip against the ground.I look down the limb to see the bend again.My left hand remembers and corresponds to the same pressure it took my right hand to get the same bend my left one is showing.It takes practice.
When you really get good you can look at both limbs at the same time bending using same pressure on both hands.Then you don't need to go from one side to the other.4" of tip movement means you still have at least a 50# bow.Does'nt matter if it's a character bow either.
Recurves are harder as Brad said.Best to floor tiller it as a long bow then bend your recurves in exactly the same and you'll be ok.I really can't believe this is news to you.It's a skill that makes a bow to brace with the least amount of stress put on a bow you can do.
loon...Like I said it's the kindest way to get a bow from floor tiller to brace there is.If a bow takes set just from bending 4" it's too wet a and let it dry some more for sure.These bows are'nt made of glass,They can handle more than you guys think.
willie & loon....Just getting it bending evenly over the whole limb and each limb matching the same amount of pressure but leaving the outside 6" tip end stiff.I still will put it on a short long string most times and check the bend quick and get my 6 to 8 inches of tip movement below handle yet around my target weight before going to the short string.
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Doing all of this slowly too once the bow starts bending even 2".Eliminating any undulations in thickess taper on the belly before doing any heavy bending over a foot or more.At brace site down the edge of your limb.Spot stiff spots.Fix em.All this to reduce any stress anywhere in paticular.Just your basic tillering a bow slowly the kind way.
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nice explanation, Ed. I am still scratching my head as to why floor tillering in the conventional way might give a "truer" bend than if done on the tiller tree.
Its always nice to re-read TBB one in a while, the chapter I found (that you might be referring to) is by Jim Hamm "Tillering" p257 TBB1.
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willie...floor tillering is the pre bending step before being put on the tillering tree.
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I trust the floor tiller bend more than the long string bend also. If I am working on a standard maybe slightly reflexed longbow all I do is floor tiller to brace. I use the long string quite a bit on elbs and also bows that have a lot of reflex. I have another method I use where I rest the ends on rollers and crank down the handle. Not much feel with this method though it does keep a highly reflexed bow under control while the limb tiller is at least ballanced out.
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I go from floor to long string (10 in. of string movement...not tip movement), to short brace height. Tiller bow.
Personally, I like the long string because I can see at a distance how the limbs are bending and I've developed a method of determining if the stave is light enough to string.
I've never seen the tips of a finished bow move more than 2-3 inches.
Just make a bow.
Analyzing just keeps you out of the shop which is where you learn. :)
Jawge
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I believe developing a good eye during floor tiller will help with seeing the true bend. Most of the time I can get a real good brace tiller just from floor tillering. I use a belt sander to tiller and constantly check floor tiller. I do that by using the same form as push/pull stringing the bow. Look down the bottom limb and check bend. Flip it over and check the other limb. With enough practice you can eliminate putting a string on the bow until you are ready to brace. In the end though I reccommend you do whatever it takes to get your tiller nailed :) Floor tiller will speed up the tillering process but it is not about speed it is not overstressing the bow by stringing it and pulling just to find a bad spot. Find your uneven spots with floor tiller.
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I've never seen the tips of a finished bow move more than 2-3 inches.
Jawge
I'm sure I'm missing something here Jawge :-\ :-\ :-\
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keep in mind, guys are making it sound easy, but are really using a combination of
floor tiller
long string
taper
intuition,,,
most guys that have made alot of bows,, could scrape one out with even taper,, and brace it skipping most steps,, and be pretty close,, on a first brace,, :) mainly by just the way it looked,,
but everything you do to have it bending evenly first brace is gonna bennefit the bow,,
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DC,
Here's my last bow at brace.
(http://img.photobucket.com/albums/v331/Jawge/Turn%20the%20Corner/IMG_3641_zps6pqppm1w.jpg) (http://smg.photobucket.com/user/Jawge/media/Turn%20the%20Corner/IMG_3641_zps6pqppm1w.jpg.html)
Here it is at full draw.
(http://img.photobucket.com/albums/v331/Jawge/Turn%20the%20Corner/IMG_3203_zpstjyell7d.jpg) (http://smg.photobucket.com/user/Jawge/media/Turn%20the%20Corner/IMG_3203_zpstjyell7d.jpg.html)
If watched as I pull on the rope and pulley and release, not much movement there at the tips.
Hard to explain without a video.
Jawge
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Gotta be more than 2-3", doesn't it? I did some tests a while back and found that, roughly speaking, tip movement is the power stroke divided by 3. So 6" brace, 21" power stroke on a 28" draw makes 7" of tip movement.
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Tip movement is pretty meaningless. Just read the weight at the point you are pulling it to. It will read pretty close to the same thing it would read if it were braced even if you are on a long string with no brace. If your string is hanging down loose at 6" and you pull it to 50# at 24" it will read prety close to that f you are to brace it even though it will have much less string movement. Most of your draw weight increase is due to loss of leverage and not from the wood actually becoming harder to bend.
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DC, it depends on how the bow is tillered. I prefer the last 6 inches to not bend much if at all.
Jawge
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I don't leave the floor until its safe to brace it with at least a 1-3" brace. Otherwise everything I see on a long string is pretty much false, that's my way of doing.
With you Drums, I gave up the long string a while back for several reasons, namely the LSL (long string lie). Now if you anticipate and work with it like Pat does, that's fine, but you gotta be able to read it. I typically floor tiller til I slap a string on her that get's a 1" brace or lays taut on the belly, whatever kind of ends up happening, and go from there. The last one I did I actually went for a 3" brace. I feel like I waste less time like this, personally.