Primitive Archer
Main Discussion Area => Bows => Topic started by: PatM on April 11, 2014, 11:11:23 pm
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You still believe that timing myth? ;)
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You still believe that timing myth? ;)
gotta plus one ya here Pat
I would love to know how timing is done !
Guy
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I use the sun dial arc for most of my timing issues! That way every thing comes out even.
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You still believe that timing myth? ;)
Yes I have been arguing against this limb timing thing for years. There's only one way, that I can see, how you might get a timing issue and that would be by making the limb tips extremely unbalance in mass, how unbalanced you would have to make them I have no idea.
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Well you all can do what ya want of course. I've been advocating timing limbs to the archers holds for 15 years or so and between what I've found in the bows I've made and the results of those I've helped, it's worth it.
I'm finishing up another today... an asymmetrical osage selfbow, showing 1/16" negative tiller after timing for split finger. Got it dyed, and going back out to start spraying now.
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I think a lot of how a bow works can come down to how it is used, and I think timing can be more of an issue with your form than anything. I have taken some videos of me shooting some of the bows over the years, and almost always the bottom limb comes home first when looking at it frame to frame. I think this is because of me pulling up on the bottom limb when I draw a bit, even though it doesn't look like it, I think my drawing arm is a bit higher than it should be and ends up "flicking" the bottom limb, persay. Since I have tried my best to correct this, (probably not successfully, :) ). But now I try to draw across my chest, instead of anchor at the chin or whatever recurve shooters do. It has helped me in accuracy tremendously to switch to drawing across my chest.
EDIT: And yes I know that elb is disgracefully under drawn, I offer my sincerest apologies, :)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming5.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming5.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming3.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming3.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming2.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming2.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming10.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming10.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming11.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming11.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming6-1.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming6-1.png.html)
(http://i1203.photobucket.com/albums/bb392/toomany7/Limb%20timing%20pics/limbtiming9-1.png) (http://s1203.photobucket.com/user/toomany7/media/Limb%20timing%20pics/limbtiming9-1.png.html)
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There was slow mo (high speed) video posted on here recently including footage of a bow deliberately tillered asymmetrically, you could see the limbs got home together.
I can't be bothered to find it, maybe someone else can >:D
Bottom line is, there is a bit of string joining the limb tips, so they must pretty much finish together.
Del
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Toomanyknots, the bottom limb is returning sooner because it's too strong relevant to the top... with respect to your holds on bow and string.
Are those bows symmetrical in design? What are their tiller measurements?
Improving the timing can help the bows draw more smoothly/evenly, reduce handshock, improve arrow flight and practically make tuning an afterthought.
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OK.
I've found the thread.
I suggest it should be compulsory study.
http://www.primitivearcher.com/smf/index.php/topic,45246.msg612828.html#msg612828 (http://www.primitivearcher.com/smf/index.php/topic,45246.msg612828.html#msg612828)
Below, is the specific clip with asymmetric tiller.
http://www.youtube.com/watch?v=6iHEiBa7zMg (http://www.youtube.com/watch?v=6iHEiBa7zMg)
Del
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So if the limbs aren't timed, do you speed one up or slow the other one down? How does one add speed or take it away from a limb? >:D
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Toomanyknots, the bottom limb is returning sooner because it's too strong relevant to the top... with respect to your holds on bow and string.
Are those bows symmetrical in design? What are their tiller measurements?
Improving the timing can help the bows draw more smoothly/evenly, reduce handshock, improve arrow flight and practically make tuning an afterthought.
These particular bows are symmetrical, all being shot almost symmetrically, save for the bottom limb being stronger mostly by feel, maybe 1/16" at the very most positive tiller. If the bottom limb of my bows are not the stronger limb, the draw does not feel right to me. I can't understand how you could shoot a bow with a stronger upper limb. At least from my personal stand point.
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So if the limbs aren't timed, do you speed one up or slow the other one down? How does one add speed or take it away from a limb? >:D
Small rocket on one, parachute on t'other >:D
Del
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please could someone explain this timing theory? not sure what you're on about really, sounds interesting though! I'd say that if the limbs return home exactly together then that bow will have very little shock or vibration felt in the bow holding hand. Does this sound right? isnt this one of the causes of hand shock?
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My goal is to build bows that are balanced at full draw... meaning, at full draw the way I hold the handle and string, both limbs will exert equal strain on the string, resulting in a bow that doesn't try to tip in the hand during the draw, with the nock traveling straight back perpendicular to the handle, and straight forward upon release, with both limb tips arriving at true brace simultaneously. If one limb's strength (relative to all factors) is stronger, the nock will be pulled toward it during the draw relative to the shelf, and move away from it upon release. I don't want the nock end of my arrow treated that way. As Del mentioned, the string will try to stop them both at the same time, but a stronger faster limb gets there first, while the weaker acting limb is still on its way. This 'distorted brace' happens for an instant until the bow can 'right itself'. This is probably the instant we see in your pictures above.
If one limb is stronger than the other, and we work to balance them, it doesn't matter if one is weakened or the other strengthened, but usually it's easier to remove wood from the stronger.
If you're building symmetrical bows, tillered positive, with the shelf 2" above the center, you have probably become used to the feel of them shifting from static balance(at brace) to dynamic (at full draw) and posible putting extra pressure here or there where you feel it's needed. A bow that is balanced might feel odd to you and you may need to make some adjustments.
You said you dont know how someone could shoot a bow with a stronger top limb. First understand that just because a bow shows the top limb stronger at brace doesn't necessarily mean it will feel and ACT stronger at full draw... or any time during the draw. Much depends on design and the shooter's peculiars.
I make my bows to feel balanced at full draw, and depending on those things mentioned, and others, sometimes my bows are tillered negative, sometimes even, and less often, positive... but they ALL feel balanced the same at full draw.
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Dragonman, yes, unsychronized limbs cause and/or add to handshock.
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There is some woolly thinking going on here >:(.
It doesn't matter what the limbs are!
One could be a limb sawn off a 50# bow and one off a 20# bow joined together as a take down...
At full draw the limbs will automatically be in balance because they are joined by a string which will have the same tension along it's entire length.
So the limbs will end up under the same force! Let's call it say it 35# for the sake of the discussion
The "50" limb will not bend so much as it did in the 50#bow and it will only be pulling 35#.
The "20" limb will be over strained and will be pulling 35#
So you see at full draw it is in balance.... (Yeah it won't look pretty tho' ::) )
If we freeze frame the bow every inch or so during the loose.... we can apply exactly the same logic to show that the two limbs are still in balance because the tension in the string is still the same along it's length.
When the bow is shot the limbs will act as one, because the whole thing is one assembly.
BUT!!!... IF we get to full draw and cut the string.... :o
THEN and only then can one limb race ahed and get home first... but without the string... it's not a bow!
Right I'm quite happy to be shown to wrong on this! If someone can point out the error of my ways...
I'm willing to go sit on the naughty step and eat humble pie, but I think my reasoning hold up, and it certainly agrees with that slo mo video.
Del
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By joe I think he's got it !
Good job Del !
cut the string :laugh: :laugh:
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Sounds good to me Del
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That's failed logic, Del. As you define it, they may be balanced IF the archer does NOTHING to alter the imbalance with his bow hand, but your balance requisite doesn't take into account the effects..... one of them being the positional relationship of the nock point to the shelf.
We always draw to the same anchor point, but with one limb's relative strength greater than the other, there are consequences... which I explained above, and you partially explained in your last post... i.e. the stronger limb won't flex as much as the weaker one... so the weaker one 'gives' to the stronger, giving away nock position relative to the shelf as it does so.
Again, since we always come to the same anchor, any unbalanced bow, especially your 50/20 bow, can/could be seen as the bow tilting in the hand at full draw, which I've seen on every bowmaking site I've visted. The more the limbs are out of balance, the farther the bow will try to tilt in the hand, and the farther the nock of the arrow will deviate from perpendicular travel relative to the shelf. There are also consequences to THIS, upon release.... arrow porpoising, handshock, inefficiency, unbalanced draw, etc.
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My goal is to build bows that are balanced at full draw... meaning, at full draw the way I hold the handle and string, both limbs will exert equal strain on the string, resulting in a bow that doesn't try to tip in the hand during the draw, with the nock traveling straight back perpendicular to the handle, and straight forward upon release, with both limb tips arriving at true brace simultaneously. If one limb's strength (relative to all factors) is stronger, the nock will be pulled toward it during the draw relative to the shelf, and move away from it upon release. I don't want the nock end of my arrow treated that way. As Del mentioned, the string will try to stop them both at the same time, but a stronger faster limb gets there first, while the weaker acting limb is still on its way. This 'distorted brace' happens for an instant until the bow can 'right itself'. This is probably the instant we see in your pictures above.
If one limb is stronger than the other, and we work to balance them, it doesn't matter if one is weakened or the other strengthened, but usually it's easier to remove wood from the stronger.
If you're building symmetrical bows, tillered positive, with the shelf 2" above the center, you have probably become used to the feel of them shifting from static balance(at brace) to dynamic (at full draw) and posible putting extra pressure here or there where you feel it's needed. A bow that is balanced might feel odd to you and you may need to make some adjustments.
You said you dont know how someone could shoot a bow with a stronger top limb. First understand that just because a bow shows the top limb stronger at brace doesn't necessarily mean it will feel and ACT stronger at full draw... or any time during the draw. Much depends on design and the shooter's peculiars.
I make my bows to feel balanced at full draw, and depending on those things mentioned, and others, sometimes my bows are tillered negative, sometimes even, and less often, positive... but they ALL feel balanced the same at full draw.
Well whatever works for you I guess. I would never tell anyone asking though to make the weaker limb the bottom one form my experience. For one, I believe the bottom limb gets stressed more, and needs to be a bit sturdier than the top. And two, it doesn't make sense. I don't nock my arrows more than 1/2" above center usually, if they were two inches above center the upper limb would need to be weaker, not stronger like you are proposing. (when you nock the arrow 2" above center, say on a 72" bend in the handle elb for example sake, one limb becomes 34", and the other becomes 38". So you have essentially shortened the top limb. And when you shorten the top limb, it becomes stronger, so you need to weaken it to balance the draw, giving the bow it's yumi like asymmetrical brace profile, aka, positive tiller.)
Edit: Fixed stupid math error, :o ;D
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I wish I could explain why my bows shoot great. But I cant. I just whittle them out and call them bows when they feel like bows. If I could explain it; I may have some useful to offer here..:) Another reason Im not much of a teacher.
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BUT!!!... IF we get to full draw and cut the string.... :o
THEN and only then can one limb race ahed and get home first... but without the string... it's not a bow!
That's one thing that boggles me, is how utterly crazy the string seems to go when I fire the bow from frame to frame. It seems to go nuts, and I shoot either low stretch linen or fast flight.
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Remember that the more accepted theory is that bow strength does not make nearly as much difference in limb speed as one might believe.
So two limbs that are at most a pound or so apart are not actually going to be in some sort of one-sided race.
The timing theory is a wildly convoluted theory to explain something that is likely far simpler.
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I've never really fully understood this whole argument about bottom/top limb & stiffness, positive tiller, etc.
With bendy handle bows and ELBs, I only set the arrow pass about 1/2" to 1" max above center anyway, so the limbs are effectively the same length. There's no riser per say, and you can set the grip wherever you want.
With stiff handled bows, the limb is only bending between the fade and tip, in both limbs. If you have a 68" bow with an 8" non-bending riser for example, regardless of where you place the arrow pass within the 8" non-bending handle, the 30" bending portions of the limbs are still the same length. Even if you turn the bow upside down. The string does become longer on the bootm limb on this type of bow, but that doesn't seem to matter to me.
Therefore, I tiller my bows from geographic center, and make the limbs bend evenly. As the slow-mo video clearly shows, the tips have to recoil at the same speed regardless, when they're connected by a string.
Making the limbs different lengths (aka Torges style) is a different story. The arrow pass becomes the fulcrum and balance point of the bow instead of the center.
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I've never really fully understood this whole argument
The more I try to, I think the less I get it, ;D.
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For me, and the longevity of the bow, I think it's more important that the tiller is even.
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The improperly tillered bow in the link that Dell posted shows a bow that must have a stronger lower limb for them to bend the way they do yet they still return exactly at the same time.
As I said earlier. If you increase the mass on the limb tip of a properly tillered bow then you may see limb timing that is off since the higher mass should slow that limb down. For a bowyer to inadvertently do this while making a bow seems unlikely since most try for symmetry.
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When I look at a stiff handled bow like this, the bending portions of the limbs (from fade to tip) are still the same length regardless of which one is up/down. The bottom limb is longer than the top if you're considering where the arrow pass is, but the bending portion is still the same. The string does become different lengths, but does this effect anything?
I've always kinda thought this whole 'gotta make the bottom limb stronger' stuff was an urban legend and myth. Seems to be a few of those in archery. People just seem to accept this as gospel, but never really stop and think about it.
This bow was tillered evenly from dead center, and it still sure seems to bend evenly in the hand. The arrow pass is 2" above center.
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Didn't look at the link but I know one of those videos shows weight added to a limb to test the theory further. Can't remember if it is a well tillered bow or not with weight added.
I know I have seen video posted by one guy who firmly believes in timing and two separate videos show one bow tipping forward on release and the other kicking forward in the lower limb. They felt right to him which is probably more what is going on.
The picture Adam posted above shows why I personally prefer positive upper limb tiller. I want the bow handle tipping slightly forward since that is what our wrist and hand does naturally if we just clench our fist lightly and hold it at arms length.
See how the upper portion of his wrist is kind of "crushed"? I don't want that. That has little to do with how the bow actually works itself but I want everything in the equation working together.
ps: look at a Yumi at full draw and note how it looks more "pointable" with the forward tilt to the handle.
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Pat, instead, I would harmonize the limbs and shape the grip to tip my hand, while not tipping the bow.
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What do you mean by 'harmonize' the limbs?
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Harmonize ="timing".
DWS. I don't like pistol grips on a selfbow so that's not an option.
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Good topic, but like some of you say if it looks good and feels good to shoot then call it a day and start another one. I just like to build. :)
I did this photo just for something to do, my bow is on the left, Bubby on the right. Both bows are an r/d design. I rushed the final stage and cut in a small shelf on the stronger limb (top), at any rate it looked like the stiffer one on the tiller stick. The photo is not the best but it looks like the top limb is longer. Rather than over tiller the bow and loose weight I let it be and having a slightly more negative tiller seemed ok. It feels good and shoots fine.
And yes Bubbys is the better tiller....... ::)
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Please, see this video:
http://www.youtube.com/watch?v=8pYVmrWzTP8
Very unbalanced bow, and 1500 grains weight in upper limb. As you can see, limbs are "timed", of course, but the bow is rotating in my hand. Same is happening if you cut the string but more pronounced.
There is videos where the weight is in lower limb and with no weight.
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BUT!!!... IF we get to full draw and cut the string.... :o
THEN and only then can one limb race ahed and get home first... but without the string... it's not a bow!
That's one thing that boggles me, is how utterly crazy the string seems to go when I fire the bow from frame to frame. It seems to go nuts, and I shoot either low stretch linen or fast flight.
That could well be an artefact of the camera. See the last of the possible causes 'Rolling shutter' in this link.
http://en.wikipedia.org/wiki/Digital_artifact (http://en.wikipedia.org/wiki/Digital_artifact)
You need a propper high speed camera to view it properly.
You will see lots of stills taken from video with loose S shaped wobbly strings and limbs that look out of kilter.
The camera certainly does lie!
There is some string vibration, but it more like a guitar sting than a length of wet spaghettii (other types of pasta are also available... :laugh:)
Del
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By the way, the Yumis are almost a completely different animal. Their unstrung profile tells me to be VERY careful about using them to compare against my own bows. Watching them in action, I've noticed that like 'our bows', they are not all tillered to suit every archer. For various archers, some bows stood straight at full draw, while others tipped forward a great deal. Some were dead in the hand at the shot, and some pitched back and forth wildly. It doesn't seem all Yumis are tillered equally well, so I'm mindful of that when studying them.
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That's failed logic, Del. As you define it, they may be balanced IF the archer does NOTHING to alter the imbalance with his bow hand, but your balance requisite doesn't take into account the effects..... one of them being the positional relationship of the nock point to the shelf.
We always draw to the same anchor point, but with one limb's relative strength greater than the other, there are consequences... which I explained above, and you partially explained in your last post... i.e. the stronger limb won't flex as much as the weaker one... so the weaker one 'gives' to the stronger, giving away nock position relative to the shelf as it does so.
Again, since we always come to the same anchor, any unbalanced bow, especially your 50/20 bow, can/could be seen as the bow tilting in the hand at full draw, which I've seen on every bowmaking site I've visted. The more the limbs are out of balance, the farther the bow will try to tilt in the hand, and the farther the nock of the arrow will deviate from perpendicular travel relative to the shelf. There are also consequences to THIS, upon release.... arrow porpoising, handshock, inefficiency, unbalanced draw, etc.
The hand is supposed to merely support the bow not grip it.
A bow does naturally pivot as it is drawn because it is (generally) not entirely symmetrical.
Why would an archer fight the natural balance of the bow??? ???
That's why modern target recurve archers (with their girly bows >:D ) have wrist straps and support the bow loosely. Even with their bows the nocking point is above the grip so the draw isn't symmetrical.
Anyhow we are in danger of arguing about how many angels can dance on the head of a pin.
I'll hold off on the naughty step and pie until I hear something more convincing ;D
Del
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"The hand is supposed to merely support the bow not grip it."
I 'grip' my bow light/relaxed. If things are designed and balanced well for the archer, gripping a bow, even stearnly, needn't have disasterous effects. If it's designed and balanced poorly, minimal human contact sure couldn't hurt on some... though there are still issues not being addressed... and adjusting the grip, by say, affecting a high or low pressure point, might help to a certain degree on others.
"A bow does naturally pivot as it is drawn because it is (generally) not entirely symmetrical."
Some bows will try to pivot, and they'll be prone to try to pivot more the farther the static/geographical center and string fulcrums are seperated by design, and more-so in the early part of the draw. The farther we draw, the more relative limb balance can overcome the initial fulcrum seperation, and we can then tiller/time the limbs to largely balance at full draw(dynamic balance) so that pivotting and nock point deviation from perpendicular to the shelf is minimalized. Still, the best drawing and shooting bows I've made and used were designed and timed to suit the shooting style of the archer so that there is no, or practically no pivot or pressure shifts from beginning to end.
For instance, an asymmetrical bow shot three under can have the static balance, dynamic balance, bow hand and string hand fulcrums all at the same spot, requiring no shifts during the draw and loose.
"Why would an archer fight the natural balance of the bow???"
I don't know, but many do. Heck, due to design and tiller, some bows REQUIRE a fight. Guess they ARE like women :^)
A better question might be... Why not design and tiller the bow to balance perfectly and be inherently tuned to the archer?
"That's why modern target recurve archers (with their girly bows ) have wrist straps and support the bow loosely. Even with their bows the nocking point is above the grip so the draw isn't symmetrical."
You're right, it generally isn't. But it COULD be with the asymmetrical/three under thing I mentioned above.
I think they do it more for minimizing human error factor anyhow, no?
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I've been reading your posts DWS and I see that you make a lot of assumptions. Perhaps you could post some pictures of your bows, perhaps at different draw lengths, to assist you in what it is you are trying to say. Come to think of it, I don't think I have ever seen you post one of your bows so I would certainly like to see one.
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To all timing advocates. How would you time this puppy? ;^)
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I always love when this comes up,I get to fill up on popcorn. ;) :)
Pappy
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Easy on the salt Pappy. You know it causes hyper-tension. Next thing you know we'll be getting into tension issues;^)
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Nice bow
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Bogaman, I'd love to time that thing. I'd do it just like I do any other bow.
Marc, I don't remember the last time I posted pictures here. I have plans to do an indepth article/tutorial on tillering/timing of the various popular designs, and have the bows glued up that I'll use, but I need to postpone it temporarily now because I sold my house and am in the process of packing. I'm now finishing the last bow I may make for a while. I'll try to post some pics of a bow or two soon.
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That is defiantly an out doors bow !
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Bogaman, I'd love to time that thing. I'd do it just like I do any other bow.
Probably not. I don't think the construction would permit that and you won't do much shaping of that handle.
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Saying that the relative speeds of the returning limbs doesn't matter is like saying tiller doesn't matter. Essentially they are one and the same, or at least both parts of the whole.
How you would go about measuring it......well......I use feel and closed eyes to tell when my bows are 'done'.
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The point is that it's not the actual timing of the limbs that's being adjusted.
It may be the way someone explains making a bow shoot smoothly but it doesn't make it real.
It's like saying your muscles burn from lactic acid when you exercise strenuously. It sounds great and makes sense because acid burns but it doesn't actually happen.
People will still use that expression forever though.
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That'd be micro tears in your muscle Pat! What do I win man?
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To all timing advocates. How would you time this puppy? ;^)
Ha!
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Saying that the relative speeds of the returning limbs doesn't matter is like saying tiller doesn't matter. Essentially they are one and the same, or at least both parts of the whole.
How you would go about measuring it......well......I use feel and closed eyes to tell when my bows are 'done'.
I don't think anyone is actually saying that... I'm certainly not.
I was saying I believe it's a flawed concept, within the constraints of a "reasonably well tillered" bow.
We all all strive for reasonably symmetrical tiller, and when that is achieved, I feel the geometry and physics does a good job of balancing the bow and the forces for us.
MY extreme example was just that.. an example.
I feel if we are looking for a scapegoat for handshock then excess tip mass (or over light arrows) is my bet (or maybe global warming ::))
Del
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The best way I have found to properly time a bow is to tie a string from one nock to the other. In California we call them bow strings.
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hehehe
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all the arguements about bow tunning etc assume that we all pull a bow with perfect posture and alignment like a machine designed to draw a bow...in reality nobody does this because we are all asymetrical imperfect humans....therefore , trying to apply exact rules of physics dont really apply ....although they may help some types of bowyers, it doesnt seem to apply to most wooden bowyers IMHO
there is a few points though...a bow string acts like a lever on the limb and if the string length below the arrow is longer its leverage effect is greater....like increasing the length of any lever increases its leverage power....this lends weight to the idea of making the bottom limb slightly stronger... so I have always put the the strongest limb on the bottom,,,but in some bows I've noticed that the upper limb gets weaker as the bow is shot in?? and in other bows the reverse happens.....
my conclusions are that wooden bow making cant be reduced to scientific formulas and thats why I like it ...interesting brain exercise though to try and understand these things
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Well said dragonman. Interesting discussion for sure. Great question Marc!
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Yes, sure do.
I can see my limbs bending and returning in unison on the rope and pulley on a well tillered bow.
Now I read in a previous post on this thread that poorly tillered bows are timed. Good luck shooting those bows.
Perhaps with a homogenous bow material like FG this would not be an issue. Wood is not uniform.
When I shoot it I can sense the limbs returning in unison.
These days most everyone (except me) pops their bow onto a form and heats it to bend it to shape and get it to conform.
Work a character bow or 24 and you may see the importance of timing. YOu'll feel it in the hand shock.
I am not on a quest to get anyone to believe in limb timing though. So it is fine.
My only quest has been to get people interested in self-bowyery.
Timing is everything. :)
Jawge
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It is entirely possible that we all are just talking about the same thing but just looking at it from a different perspective. Making a bow, to me, is getting the limbs balanced with uniform tips so that they are very close to the same and bending smoothly so that it neither rocks back or forth when drawn. I call that proper tillering of a bow. Some may just call it timing a bow.
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yes I agree...marc..."bow timing" is a misleading term, implying something other than correct tillering is necessary....when any archer with some experience can recognise a well tillered bow as soon as he shoots it...without any specalist knowledge of so called bow timing...and generally if both limbs are tillered to within !/8"" a bow will shoot well
why complicate matters? maybe to appear more intelligent? or in possession of specialist knowledge? (just teasing of course!!)
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Marc, depends on what you call a well tillered bow.
You are achieving good timing on a well tillered bow by choosing good bow wood and heating.
Some bowyers these days tiller by eye only. There is much more to it.
With the last osage bow I built each of the limbs came into the handle at different points.
It does not have that picture perfect tiller. Yet it draws and shoots beautifully. Pressure is even on the handle. The arrow is away with a silent push because the limbs are timed well.
Jawge
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Marc, depends on what you call a well tillered bow.
You are achieving good timing on a well tillered bow by choosing good bow wood and heating.
Some bowyers these days tiller by eye only. There is much more to it.
With the last osage bow I built each of the limbs came into the handle at different points.
It does not have that picture perfect tiller. Yet it draws and shoots beautifully. Pressure is even on the handle. The arrow is away with a silent push because the limbs are timed well.
Jawge
Quite frankly George, a well tillered bow is well tillered regardless of whether it has character or is picture perfect, at least it should be. Now if you are suggesting that all I make are picture perfect bows then I guess you haven't seen them all. Most of the bows I make are for someone else or for articles and as such need to be as free from character as possible, at least the ones for other people. Character bows are nice but the character reduces their reliability and that's not good for warranty. I'm sure that given the choice most people would pick good bow wood rather than mediocre bow wood but there's always the exception to the rule. As far as tillering by eye only, that's a bit of an assumption. I would tend to think that most all good bowyers tiller by eye, by feel and probably by gut as well.
I'm sure your Osage bow is well tillered. How about posting some pictures of it?
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....exact rules of physics dont really apply ....
??? "Rules of physics always apply." ;D I know what you are saying - I just couldn't resist replying as my college physics professor would say! >:D
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Bingo George.
Marc you said, "Making a bow, to me, is getting the limbs balanced with uniform tips so that they are very close to the same and bending smoothly so that it neither rocks back or forth when drawn. I call that proper tillering of a bow. Some may just call it timing a bow."
I'm partly of the same thought process, but don't need the tips to be uniform, the same distance in front of or behind the handle, coming down the same distance on the tree, etc. One can be straight and the other reflexed, or whatever. It can be a really weird, unique thing, and can still be timed/tillerd/sync'd correctly to the archer's holds. It may look bizarre to many folks at brace, but I don't much care so long as the limbs' relative strength allow the arrow nock to come straight back and leave straight ahead... she's good.... she'll feel like an equally well tillered/timed straight bow... and she's gonna do exactly what she was meant to do... with the good attributes we claim to value... and in the end, the braced profile simply is what it is.
I used to heat straighten stuff more than I do now. I understand now that it was more just to please my eye cuz like most folks, I grew accustomed to symmetry, now I usually only heat and bend if I have to.
I concur though that when making bows for the 'uninformed' I will do more heat correcting than I would for myself.
To me, 'correct tillering' encompasses much... and high on the list of importance are limbs that are synchronized such that neither overpowers the other when drawn as the archer will. Due to their inherent irregularities, in order for wooden bows, especially selfbows, to accomplish this, for any given archer's holds, their braced profiles may vary considerably. Many folks however, use the same predetermined brace height measurements as their beacon and ultimate goal throughout the process on ALL their bows. This is a mistake IMO.
Dragonman, I'm not trying to apply direct laws of physics to my bows, at least not with blinders on... quite the contrary. I do whatever needs done to get the bow to do best what it is meant to do... shoot an arrow straight away with purpose... not porpoise :^) while treating itself, the archer, and the arrow most kindly. Two bows that LOOK the same unstrung, may act and look different later in the draw due to invisible inherent differences. Tillering/synchronizing the limbs the way I do makes neither more difficult, may make them look different at brace and/or full draw, yet function and feel the same.
Conversely, it could be viewed that those who are 'trying to apply direct laws of physics' to their bows and tillering are those who tiller to specific predetermined brace height measurements and 'expect' their wooden bows to behave a certain way... which they always don't... those who do what they're told whether best for them and their own bows or not.
Talk about making assumptions :^)
If someone looks at one of my bows and tells me the "tiller's off" because it's negatively tillered, or not what they'd otherwise 'expect'... "I need all my bows tillered 1/4" positive"... or some such... I'm going to have to assume they're making too many assumptions :^)
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DWs. I agree with what you say....I think it is just the word timing that confused me
mwosborn.....I agree with you too,......rules of physics do always apply......but in nature there is no symetry untill you get down towards a molecular level, a bow may appear to be unbalanced, but stilll be perfect, like a flower that isnt symetricaly perfect, but still created out of perect underlying symetry...so is still a perfect expression of creative force.....a like to see bows like this.....nothing is perfectly in balance in this world....or else it would cease to exist....not to say we shouldnt try to acheive it
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dang...yall think too much...scrape scrape...bend bend....lol
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One last thing...my last osage bow with the different limb entry points does not have a brace or full draw tiller pleasing to the eye but it is well tillered.
Jawge
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DWS
Actually you only think you are in partial agreement. You were assuming that I meant that the tips were bending uniformly to the same point but that is not what I meant, possibly if you re-read what I wrote you will see this. What I meant was that the tips need to be uniform in mass/size. Unbalanced tip mass contribute to hand-shock as does the tiller. Now if you really want to be able to tell if your bow is well tillered/"timed" try shooting 4 or 5 GPP arrows out of her. She'll let you know quickly if you've done a good job or not
P.S. You may like symmetry more than you think you do.
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Or actually don't hold onto the bow at all on release. The distance the bow travels tells you how much hand shock you actually cope with and call "dead in the hand".
Whether the bow leaps strait forward or cartwheels end over end will tell you something as well.
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Marc, ok, gotcha.
I really need to get out there and do some more spraying. Ain't gettin no bows made in here :^)
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Please, see this video:
http://www.youtube.com/watch?v=8pYVmrWzTP8
Very unbalanced bow, and 1500 grains weight in upper limb. As you can see, limbs are "timed", of course, but the bow is rotating in my hand. Same is happening if you cut the string but more pronounced.
There is videos where the weight is in lower limb and with no weight.
Very interesting video. I can almost swear I see the lower limb reach brace a split second before the top limb
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Who remember this one:
http://www.youtube.com/watch?v=GuvGkApgsm4
I will get the high speed camera for one week again, so I can film, what is happening when I dry release & not gripping a very unbalanced bow, or bow with different weight limbs. The camera is real high speed camera, so all the phenomena you see will be true.
So, what do you think, will happen? Will the bow jump just forward, regardless of the tiller, like the in the video here? Or, if limb timing is different, will the bow rotate in air (it should)? Ok, you do not need a high speed camera to see that, but hopefully there is something else to see with high speed camera. If you have ideas, how to film tiller/limb timing issues, please tell!
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Marc - I can analyze the full resolution video to see, if that is true. Lets suppose, that the bow is in brace, when the string is straight - which means, that neither limb can move forward...
How do you define "brace" because the bow is rotating? The lighter limb of the bow is moving faster but still the both limbs are at brace same time.
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Still at it I see. ;) Interesting discussion for sure ,but I do know one thing,I ant dry firing one or shooting one open handed to find out if it rotates on the ground on goes straight out in front of me. ??? If it happens to do just what is is supposed to,what ever that is you still are taking a good chance on having a broken bow,so whats the point. :-\ :) :) I agree Jawges on a character bow it is all about the feel, I do heat/steam bend a lot to get the worst out on most bows but on some you can't get it all out and you have to go by the feel and a lot of looking.Then it is all about how it shoots/how it feels in the hand and how it feels when it hits home. :)
Pappy
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Don't recall ever having a bow do any spinning when shot from an open hand
Unless you are talking the string following the arrow around ,non center shot bows will do that and typically hit your hand then bounce back the other way and the top limb will move forward more from being shot from above your hand ( since it is the pivot point )
Maybe I am just fortunate to get this timing thing right without even knowing it! :laugh:
Have fun
Guy
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Marc - I can analyze the full resolution video to see, if that is true. Lets suppose, that the bow is in brace, when the string is straight - which means, that neither limb can move forward...
How do you define "brace" because the bow is rotating? The lighter limb of the bow is moving faster but still the both limbs are at brace same time.
I guess it would be pretty difficult to tell when one tip gets to it's original resting place. The archer is probably the only one that can tell and that would be by feel.
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Here's my take.
It all comes down to how much the string stretches throughout the process. If there is zero stretch, then the limbs are geometrically constrained and the limbs would be perfectly timed. This is because they would have no other option due to the string being of a specific and constant length. Given a consistent grip and finger positioning, they would need to arrive at the same corresponding points at the same times, every time. If the limbs are improperly tillered they will have different stress cycles, which may cause unwanted stress peaks at certain times, but the limbs will have perfect timing.
But if we have a dynamic string then that can change. Now one limb can gain on the other temporarily until the string reacts to equalize the situation. But this will only happen if one limb is stronger than the other, or if one limb has more mass to move than the other, both of which proper tiller and design should take care of.
In order to have perfect timing with a dynamic string you must have limbs that are balanced in both strength and mass. That doesn't mean that the mass or the strength are equal for both limbs, but that the strength/mass ratios are the same.
On a symetrical bow with relatively homogeneous characteristics, this kind of balance would show itself to us as a nice even bend across the entire length. But for asymetrical bows or character bows, a perfectly even bend isn't always ideal.
I'd guess that timing becomes less and less meaningful as we upgrade to strings with less and less stretch.
These are all just my intuitive thoughts based on what I know so feel free to comment or critique them.
Since we can't judge timing by eye very well, we focus on all the components that lead us to it that we can readily see and feel like proper tiller, and symmetry. I think we're all striving for the same final result, we're just looking at different related characteristics to get there.
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I would be interested in how others define and quantify "proper tiller" and "symmetry".
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With reasonably symmetrical systems it is easier to think of the motion of the bow as a compression of the distance between the nocks and not so much a lateral motion. That way you can mentally keep one nock motionless and consider the motion of the other relative to it. In this case, there is no option other than a perfectly 'timed' return to brace.
The further away from symmetry you go the further away from this perfect innate timing you get. Tillering is designed to (in most cases) closely approximate that symmetry such that timing is not really an issue. (This is a little bit of a mental exercise from here as I am only passingly familiar with Yumis.) The Japanese bows are about as far from symmetrical as you can get. Timing these bows becomes not really an issue though either because the bottom limb moves so little relative to the top limb that there is no difference in timing between 'return' to brace for bottom nock as it barely left brace position in the first place-which means 'timing' itself is not a huge concern in either set of bows-symmetrical ones because it is automatic and unsymmetrical for practicality.
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Nice post Son of Massey. :)
I like your trick of moving the frame of reference to one nock.
Del
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Whooo only 44 post in 9 years and now all this to say !
While the name says son I perceive you are not all that young from those posts
I think you gave a good sumation too , thanks for chiming in!
Guy
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I would be interested in how others define and quantify "proper tiller" and "symmetry".
I would define proper tiller as a tiller that equally displaces the stress over all the parts of the bow that are intended to bend.
I would define symmetry as symmetry. Its a pretty concrete concept without much room for interpretation.
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Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement")[1] has two meanings. The first is a vague sense of harmonious and beautiful proportion and balance.[2][3] The second is an exact mathematical "patterned self-similarity" that can be demonstrated with the rules of a formal system, such as geometry or physics.
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If it's the same "Son of Massey" he may not have many total posts but he has been on here forever as one of the originals from when the message board started.
He was a prolific poster as a teenager about 12 years ago.
Many people took a break when the board was off limits unless you subscribed.
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Hmmm, well, seems to me a bow can be 'properly tillered' while stressing all bending parts equally, OR it can be properly tillered if the outer limbs are caused to bend a little less, or more, for whatever reasons we deem necessary.
Does 'properly tillered' mean tillering a bow to a predetermined measurement at brace, say, 1/8" positive, regardless of unstrung profile and differences In limb shape? Or does it mean something other?
I know what symmetry IS. But when and why should symmetry matter in bow making? If a bow's lineal measurements are identical on either side of the centerline, it is symmetrical in that sense, but what if that bow has one limb straight and the other has deflex as viewed from the side, should symmetry be maintained in its tiller profile? If not, then what should guide our efforts?
I'm still not convinced timing is unimportant or that all are 'timed' because the string stops both limbs from moving at
approximately the same time. Timing to me is something different. It's more dynamic. Good timing is causing the limbs to 'give' to the string fulcrum equally, so that it, and the arrow nock, comes straight back perpendicular to the handle/shelf. If one limb is stronger than the other, NOT at brace, but relative to the bow hand and string hand fulcrums, it will flex less, and the string fulcrum and arrow nock will move toward the stronger limb, relative to the shelf. Anything more than a wee bit is less than good timing. Imho.
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DWS, so what happens if the stave has a couple of knots on each limb?
When I tiller knots I tlller them to not bend as much as the rest of the limb. That will certainly affect how the tiller looks.
So what is the stave has some natural twist, it will affect the appearance of the tiller.
I don't always heat out twist. I look at both sides and take mental snap shot of each to arrive at common ground.
Then there's prop twist ...LOL..which I do not heat out unless excessive.
So you see timing becomes important as does using a few of your other senses for tillering.
Caveat: this is what Ido and have done since the late 80's...not looking for converts to my way of doing things. Gotta go.
Jawge
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Hmmm, well, seems to me a bow can be 'properly tillered' while stressing all bending parts equally, OR it can be properly tillered if the outer limbs are caused to bend a little less, or more, for whatever reasons we deem necessary.
Does 'properly tillered' mean tillering a bow to a predetermined measurement at brace, say, 1/8" positive, regardless of unstrung profile and differences In limb shape? Or does it mean something other?
I know what symmetry IS. But when and why should symmetry matter in bow making? If a bow's lineal measurements are identical on either side of the centerline, it is symmetrical in that sense, but what if that bow has one limb straight and the other has deflex as viewed from the side, should symmetry be maintained in its tiller profile? If not, then what should guide our efforts?
I'm still not convinced timing is unimportant or that all are 'timed' because the string stops both limbs from moving at
approximately the same time. Timing to me is something different. It's more dynamic. Good timing is causing the limbs to 'give' to the string fulcrum equally, so that it, and the arrow nock, comes straight back perpendicular to the handle/shelf. If one limb is stronger than the other, NOT at brace, but relative to the bow hand and string hand fulcrums, it will flex less, and the string fulcrum and arrow nock will move toward the stronger limb, relative to the shelf. Anything more than a wee bit is less than good timing. Imho.
Symmetry does not always mean in appearance.
The arrow will move towards the top or bottom limb if the nocking point is incorrect
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When I think of limb timing I am thinkng in terms of the arrow going in a straight line when I draw it back and a straight line when I release it. In reality your finger placement when drawing it back will slighlty change where the arrow is situated once you release the string. The arrow is the only thing holding the limbs back when it is accelerating so it won't return exactly as it did when you drew it back. I tiller by pulling it back where I knock the arrow and not where my fingers are going.
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Exactly George. Knots, twist, humps, dips, refex in one, deflex in the other.... there are plenty of reasons that a wooden bow should NOT be tillered to reveal symmetry, or not have the limb tips travel the same distance, etc.
Marc, to me, the nocking point is 'incorrect' if it is anything other than what I tillered the bow for. I set the nock point at 3/8" above the shelf and then time the limbs by adjusting their relative strength, while pulling from where my string hand will, so that the 3/8" high nock point comes straight back. When the bow's done, I tie the nock point on where planned and it's over. There's no moving the nock point up and down trying to mask built in issues. I find it easier this way. But like George said, I'm not trying to say folks have to do it my way.... just offering food for thought and an option perhaps.
Badger and I are doing nearly the same thing on our trees, we merely pull the string from a slightly different place because i disagree with his 'arrow holding the string back' theory :^)
I may try it his way one day, then mine and see if there is any noticeable difference. Maybe I'll try it on the bow I'm finishing now.
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Well I don't use a tree so maybe that's the difference. I prefer to tiller with the bow in hand. That way I can feel what it's doing
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Im not sure if they come home at the same time or not. Makes sense to me that they would. I do know if the limbs are tillered different it will be reflcted on the chronograph. I like them to both bend the same for the way I shoot. I trace one limb at brace and flip to the other side. If it looks like 2 lines I tiller until its one line. Learning that helped me out a lot. Jesse
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Wow Pat that is some memory you have got, I did not expect anyone would recognize me.
Del, it is always helpful to simplify a model as far as one can. Sure you miss details, but extremes highlight truisms well.