Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on August 26, 2018, 05:48:31 pm
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What is the nock point height adjustment compensating for?
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Clay Hays has a great video on tuning your arrows where he explained that. Its on youtube. I think again its called tuning your bow and and arrows i am pretty sure. It also has to do with sort of the same thing spine arrows do with paradox. How non center shot bows will need lighter spine arrows to shoot around riser. The nock point on string does sort of the same thing and helps how the arrow pushes off of the shelf/hand. he said it is very important to adjust it a 1/8" at a time starting at 5/8 above shelf with a bow square then working your way down. This is what i can remember .
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DC i just looked in my book marks and it is called tuning your long bow,recurve,and self bow for perfect arrow flight. I wish i knew how to share it on here but i am a "PRIMITIVE" man...lol computers confuse me..lol
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Good video but not what I'm looking for. Maybe approach it from a different tack. If I adjust the nock height on a bow for me, will it be right for everyone that uses that bow? If so is there something about the bow that determines what the nock height should be?
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Hypothetical questions on a rainy day, love it.
Assuming every archer draws the arrow the same distance, and assuming every archer uses the same type of release, I would have to believe that the nock height is good for everyone. However...not every archer draws the same distance nor uses the same release; for example, the Mediterranean draw would put an ever so slight different stress on the bow limbs compared to a pinch release.
Non human factors might include how well the bow has been tilled, and placement of the arrow shelf.
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While on a tillering tree I observe path of draw to be sure it's in a straight line.I never have problems then finding the sweet nocking point of arrow and arrow flight is always good then provided right spine arrow is used.Even when others shoot my bows provided that they grip the bow the same as me.
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"If I adjust the nock height on a bow for me, will it be right for everyone that uses that bow?" No, not for everyone. Only for those who apply pressure to the bow and string the same way that you do. It's a matter of degree... so the farther they vary from 'your way' of shooting, the farther they'll move away from a well tuned bow.
"If so is there something about the bow that determines what the nock height should be?" Yes, kind of.... there are several factors that are inextricably connected/related that together determine a bow's dynamic balance, or imbalance. The bow hand fulcrum, the string hand fulcrum(largely determined by nock point location), the strength of each limb, even static balance and some other design basics. A change in any one of them can affect one or more others and the resulting dynamic balance. All linked, all relative.
The nock point is the easiest thing to adjust after the bow is finished, so that's probably why it's been given more credence than the other factors by archers... which carries over to bow making because it's those archer's that become bowyers. But bowyers would do well to think of it a little differently, and not think of the nock point location separate from those others, as an afterthought, merely as an adjustment, or 'fix'. If you have to move your nock point around in a search for good arrow flight, there's a very, very good chance the tiller isn't best for you. I put the nock point exactly where I designed it to be, to elevate the nock end of the arrow on all bows by 1/8", and then balance the bow relative to my fulcrums, throughout the tillering process, to shooting... and expect perfect arrow flight right where I put it from the first arrow shot(unless there's an arrow spine issue). It's very rare that I have to move it afterwards... in fact I don't remember the last time. Some folks build bows backwards, imo. Reverse engineering. Why?
To reiterate my point, and perhaps dig a little deeper into the "everyone that uses the bow" thing.... since nock point height affects where an archer's fingers are on the string(the string hand fulcrum), it directly affects dynamic balance. That balance or imbalance affects arrow flight, up and down, aka porpoising. Ok, that said....
The other fulcrum is the bow hand fulcrum, and even if a second archer grips the STRING exactly as you do, if he applies pressure differently to the handle, THAT fulcrum is moved, which also affects dynamic balance, and can cause a need for the tiller at brace to be changed, OR if the bow is done, for the nock point to be moved in an attempt to affect the relative limb strength in a good way.... or perhaps he could adjust his grip on the bow handle. All linked. All relative to balance.
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I think something to keep in mind is that when we take our fingers off of the string the bow suddenly forgets how we are holding the bow and how we are pulling the string. It is now responding to the arrow because the arrow is the only thing holding the string back.
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If the nock point depends on tiller and balance and stuff why do we seem to always have the nock point above square? Couldn't a bow happen to be tillered so it wants the nock point below square?
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If you tiller so your nock point is above square the arrow more or less clears the shelf or has very little of its weight on the shelf, if you tiller below the shelf will interfere with the flight.
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I think something to keep in mind is that when we take our fingers off of the string the bow suddenly forgets how we are holding the bow and how we are pulling the string. It is now responding to the arrow because the arrow is the only thing holding the string back.
I always wondered what is happening with a three fingers under release. May be the arrow gets an additional punch or momentum? Lifting above the shelf.
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Yes, I realised that. What do you do when tillering to ensure that the nock point will be above square? Is this the reason for the lower limb being stiffer?
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As I said, I set it 1/8" high, sometimes less, above square, then as I'm tillering, I adjust the strength of the limbs relative to the other factors I mentioned above so that the nock point comes down a plumb line I have drawn on the wall which indicates straight travel, i.e. square to the shelf and handle. If it comes straight back, it will move straight forward upon release... which means the arrow will fly straight away without porpoising up and down. It does other good stuff like eliminates vibration and shock too.
I don't believe that the lower limb should necessarily 'be stiffer'. And by 'be stiffer', I assume you mean how it looks as it's viewed from the side at brace? That doesn't mean squat to me. I concern myself instead with how the limbs act relative to the fulcrums as they're being drawn.
If I want the bottom limb to ACT a tiny bit stiffer, which I do sometimes, I will make it so as viewed on the tree at full draw, relative to my fulcrums. Dynamically balanced, but favoring the bottom limb just a hair. Even done that way, many bows will show an even tiller... or even negative depending on the shape of the limbs to start.
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Do you use a standard tillering tree(if there is such a thing)? A saddle for the bow with a pulley on the floor under it?(both on the plumb line) Do you put the bow on the saddle as it will be shot or do you centre it?
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OK, I drew a plumb line. It's the black line you can see on the yellow tape. I put the bow on the saddle as I would shoot it. If I put the draw rope so it's pulling down the plumb line it's about 2" left of the nock point. Doesn't look right to me ??? ???. Should the plumb line be over to the right in line with the arrow pass. You can just make out the pass line to the right of the saddle.
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I put mine just below the arrow shelf maybe 1/4 to 1/2" this usually gives me an arrow nocking point of about 1/4" high.
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I put mine just below the arrow shelf maybe 1/4 to 1/2" this usually gives me an arrow nocking point of about 1/4" high.
Sorry, your what?
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I tiller from the center until there is 1 inch to go and then finish it off in front of a mirror or have my daughter or wife snap a digi pic. I aim for even tiller or the bottom limb about a 1/4 inch stiffer at full draw. Jawge
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I put mine just below the arrow shelf maybe 1/4 to 1/2" this usually gives me an arrow nocking point of about 1/4" high.
Sorry, your what?
The plumb line
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Put the hook on the string where your string hand fulcrum point is (center of pressure), for me, that is the middle of my middle finger. And like Badger, when it's all figured out, my fulcrum, the center of my middle finger is 1/4" below the shelf.
But you need to lay it out for yourself. We grip the string differently, our hands and fingers are different size, etc. Do it right there on the wall. Mark the handle and shelf location. Measure up from the shelf(to the right of the tree cradle if the top limb is to the right) to the bottom of the nock point, subtract the thickness of the arrow nock and half the width of your middle finger, if shooting split. That's where you pull the string from, and that's where you draw the plumb line down the wall.
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Measure up from the shelf to the bottom of the nock point
I'm having trouble understanding this.
Lets go on a little further in how you use this. I always put top limb to the right and pull down on the string.
So we have everything mounted and a plumb line marked. We pull on the rope and the idea is that the hook should follow the plumb line right to full draw. Am I right so far? Lets say the hook travels to the left of the plumb line. What do we do to the tiller to correct that?
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My arrow pass is about 1.25" above the self but that can vary depending on tiller.
Then I put my bow square on the braced bow, mark a series of lines around the string where I think could be the possible nock point, and go out and shoot.
When I'm happy with the flight I'll wrap a 1/4" by 2" strip of duct tape and leave it for awhile. When I'm happy with the spot, I'll tie on my nock point. Simple.
What is good arrow flight?
http://traditionalarchery101.com/selfbowcare.html
Jawge
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Something I just thought of. If you design and engineer a bow sort of around the nock point or you just make a bow and then adjust the nock point does one bow shoot any better. Why is one way better than the other?
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If I use a tree I hook rope where I think nocking point will be if I am sure which limb is up, which I try to start out knowing but could change. I do the majority of tiller in the hand now. I guess once I am sure which limb is top I am sort of designing bow to the nocking point since I try to pull as close as possible to where I think it will be.
Anybody know how true "primitives" dealt with nocking arrows and getting the best from bow??
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DWS, do you think you could post a picture of a bow on your tree? Maybe that would sort out some of my confusion. I'm trying all sorts of configurations and nothing gives me a warm fuzzy feeling :D
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"We pull on the rope and the idea is that the hook should follow the plumb line right to full draw. Am I right so far?"
Yes, generally. Except, the farther apart your bow's center and string fulcrum, the harder time you'll have getting the hook to follow the line early in the draw, but you can still tiller it so it gets there. At full draw, they should all be balanced, or very nearly so... there may be reasons to leave this or that limb a hair stronger, dynamically. This is an additional reason I prefer asymmetrical bows, for myself, at least. The bow center and fulcrums are all closer to one another, within a fraction of an inch, or can even all be put in the exact same place in some cases(three under), and the bow draws in a very silky smooth clean straight line from beginning to end. Once you feel it, you'll likely not want it any other way.
"Lets say the hook travels to the left of the plumb line. What do we do to the tiller to correct that?"
Before I answer, I need to know whether your bow is being supported in the tree so it cannot tilt on the cradle, or if it is allowed to move freely. To start at least, because it's a better initial indicator, I like the handle to be perfectly level and supported so that it can't tilt. Get the handle section level. Don't worry about whether one tip is in front of the other. This mistake is often made.
When the handle is level and supported there, the hook will drift toward the stronger limb as the limbs are flexed when pulled from our string hand fulcrum. Even/also when long string tillering, it will go toward the stronger limb. That's why I like to use the long string on the tree instead of floor tillering. I get an early indication of dynamic limb balance, and begin making early adjustments, which I think ultimately helps retard set in the limbs. And by stronger limb, I don't mean how it 'looks' at brace, I mean stronger relative to the other limb and the string fulcrum. Stronger in how it acts... indicated by how the hook travels.
Weaken the limb that the hook drifts toward. That's the stronger limb.
DC, this is what I always liked about you. You're inquisitive and ask the questions I wish all would ask... not of me necessarily, I'm a busy guy... lol... of themselves... of their work, of their bows. Bows know and try desperately to convey to us what they need. 'Why does the bow tilt in the hand?' 'Why does the bottom limb always take more set?' 'Why do they all feel and shoot differently?' We should listen.
I'm telling you guys... you can build bows that are inherently tuned and shoot the same. You can just as easily, or more-so, craft them so that they'll shoot that first arrow perfectly, predictably... one bow after another, than you can while trying to move the nocking point or change your grip on the bow, or retiller it afterwards. Blech. Not me. This is simply building in a straightforward, predictable manner from the get-go to achieve what we all value in our bows, no guessing, no backtracking.
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Ok. Here come the pics... :OK
Here's a roughed in trilam... bamboo/yew/osage
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Pulley down below. Plumb line on left and right so bow can be flipped. That was my old shop. I now have 4 pulleys, 2 on the left(for split and 3 under) and 2 on the right(for split and 3 under)
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Long string, not yet flexed enough to brace, but you can see the hook is drifting toward the bottom limb on the left.
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close up
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After scraping and sanding on the left, bottom limb a little bit. Didn't take much.
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she's trackin'
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low brace
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pulling toward the bottom limb again just a little. Need to weaken it a tad if ya want it perfect. Should go without saying, but these relative strength adjustments are done in conjunction with tiller adjustments that remove flat spots, adjust alignment, and such too, right...
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fixed, exercised, checked, then braced a little higher
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right down the line... on the way to full draw
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...
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It bothers me for some stupid symmetrical-minded reason that the profiles of the limbs are a little different. The tiller isn't off, it's just relevant to how the bless-ed thing came out of the form, but this it a very sweet shooting bow. The most memorable arrow I ever shot out of it was the first. It almost felt like I didn't have a bow in my hand. Perfectly balanced on my middle finger to carry, balanced throughout the entire draw, and that first arrow flew straight as a laser. Never forget it. Plan the work and work the plan.
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DWS...I could'nt of explained it better myself.I use the same method.
(https://i.imgur.com/wVBzN0u.jpg)
In doing so I find very little problems finding nocking point on bow after bow.
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Thank you very much. It will take me a while to digest and try this. have to modify the bottom of my tree. I use a double block system so I only have to pull half as hard so I have to sort that out. Thanks again, you went above and beyond :D :D
Oh, how wide is your saddle, 4"?
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Wow! Left or right of plumb...(emojis don't work or there would be some here)
I never have seen a tree like this or thought of the plumb line method! Makes me want to take all my past bows and check em with it but that might really hurt my ego.
That is awesome and I'm sure it could improve my tillering results quite a lot!
But, Dang it, I now have to go get to work on an improved tree set up.
Thanks Fellas and thanks DC for this post.
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You betcha, Dc.
BowEd, looks like you're pulling through the center of the handle. Can ya shoot like that? I don't think yer doing it how I do it... unless yer stringwalkin.
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Before I answer, I need to know whether your bow is being supported in the tree so it cannot tilt on the cradle, or if it is allowed to move freely. To start at least, because it's a better initial indicator, I like the handle to be perfectly level and supported so that it can't tilt. Get the handle section level. Don't worry about whether one tip is in front of the other. This mistake is often made.
I've always let the bow move freely so I tried it both ways. This works well if the bow can't tilt but doesn't seem to work at all if you let it tilt.
I'm trying a bow now and put it on the tree with the top to the right, it drifts to the left about an inch at FD so the bottom limb is heavy. So I turned the bow end for end and tried it thinking that I should see the reverse but this way it follows the plumb line straight down. Any ideas, answers :)
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Yes, 4" wide, because that's how long I make my handles, and it supports the handle only near the outside edges. That way it won't tip, even if there is a significant disparity between their strengths, relatively speaking. If it's WAY off, it will still tip.
That will get you a good start. Following that, I made inserts that drop down into the cradle that can be swapped out or moved to support it anywhere an archer might prefer his bow hand pressure point... or used to FIND the dynamic balance point of any bow in which it's unknown.
And yes, you're right, it makes you want to test all of your previous bows... but I'm not sure I'd recommend it. I ended up retillering and refinishing a bunch of them.... finally had to stop... cuz I preferred to build new ones. I still do it once in a while though. Sometimes curiosity just gets the better of ya.
Btw, I do all of my bows this way... glass bows too.
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Good point, flipping them end for end on the tree is a necessary verification. I do it all the time just to double check everything from pulley position to handle shape. The tree must be identical both ways, 1/16 or 1/32 of a difference between the height of the handle support of the left and right side projects out to a huge difference at the tips. Same with pulley position. You cant balance a bow if anything is off. The plumb lines, on left and right side, must be the same but exactly opposite.... flipped back and forth without altering the tiller, the bow should ACT the same each way.
You MUST take the time now to make this right. It might be a pita today, but after you do, I promise it will be worth it and will reward you in spades.
I used a 4' level to check my 4" handle support and checked the level twice before I used it.
Level the cradle best you can. Plumb the lines and pulley as best you can under your fulcrum. Check and adjust and check and adjust. It's worth it.
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I did it on the same side of the tree ie. the same plumb line. I swung the bow around and measured to where the arrow pass would be if the bottom was the top. I'm thinking that with a wonky stave getting the handle level could be a problem and if you get the level out you may be weakening the wrong limb. We'll see :)
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DWS....I believe your right but don't see why it should'nt work for someone else either.My arrow passes are usually 1.5" to 1.75"above center on all my bows.Pressure point on bow hand is dead center on bow.Right on the Y of my thumb and index finger pretty much using a bulbous type handle.I always cant my bows when I shoot except when taking pics for full draw and I usually take pics after bow is shot in.I always demand perfect arrow flight/hit where I'm looking/and very little or 0 hand shock.The string nock is usually around 1/4" above arrow pass on string with little variation on all bows and arrow snaps on under it.If that little variation is sting walking then so be it.I shoot split finger.The proof shows me no change tiller durability of my limbs.I shoot a lot on new bows and all my bows in general to say this.
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I started a new bow using this method from the get go. Trying to figure out anything on an existing bow just seemed to confuse me. Anyway I'm only to about 6" of string travel on the longish string. Probably just barely to brace height. As I pull it down it looks like it goes to the left and then back to the right. Am I seeing things or is this normal?
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DC, it could be normal. Just realize, what's normal in one bow design may not be normal in the next. Much about how a bow acts on the tree, and in the hand, during the draw depends on its design. Is the bow you're talking about of symmetrical design or asymmetrical? Symmetricals tend to have a bow hand fulcrum that slides more under the hand as the bow is drawn, and they take longer in the draw cycle to 'correct'. They're also more prone to tipping initially in the draw. But if the bow is held stable in the tree, this sliding fulcrum can reveal itself in how the hook drifts relative to the line. It can very well be that properly tillered in the end, it drifts away from the line a bit, then back nearer as it approaches full draw.
BUT, it seems odd to me that you're seeing it happen so early in the draw. Asymmetrical bows tend to tow the line earlier, but even they don't go back and forth in just 6" of draw. If I were you, I'd make double/tripple sure nothing is tipping initially, even a hair. Watch the handle section very, very closely when you first pull the rope. Clamp it down if you can.
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One thing I have to keep reminding myself is that it's the straight draw we're after. I keep thinking of things that can change the way the hook moves, like the asymmetry you mentioned. I think, wait, that's not right and then remind myself that as long as the hook is going straight down everything is cool because that's the objective. When I get this tillered out I'm going to re-rig the tree and pull it the way I used to. That may help me suss this out.
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Keep in mind too, balance at full draw is most important... not exclusive though. In other words, dynamic balance at full draw is the goal, but not the only one, because the greater the percentage of the draw, and the more closely, that the hook follows the line, the better that bow will treat the arrow, the archer, and itself. As you hone in on it, you'll feel it and see it... and soon, you'll expect nothing less.
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Just to double check. The hook following the line is "balance" right?
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Yes, it's basically dynamically balanced if and when actual shooter fulcrums are accurately mimicked on the tree, and the hook is on the plumb line at full draw.
Once you get there, you can even further 'fine tune' it by putting a real fulcrum under the handle(allowing the bow to tip), and then adjust relative limb strength so the bow sits level at full draw, i.e. 'placing' the precise location of the fulcrum where wanted by weakening the stronger limb. This method is also quite revealing of how things relate to bow functions.
You could do any of this stuff this with any bow you have made previously. It's humbling though ::)