Limb tip to string angle, bow length etc

Rog600

Member
I've measured various angles using the Technique coaching app and see that my son, has a much larger string angle at anchor, allowing him a very definite chin and nose reference, whereas mine is a much smaller angle. Until recently I had a nose and side-of-chin anchor but was using the top of my thumb under my jawline. I now use the top of my finger which has moved everything 'under', my release has improved (much less plucking), few shots heading left etc., but i now don't reach my nose with the string. My horizontal group has improved but my vertical grouping has suffered. A longer bow would increase the string angle at full draw but I'm already using a 72" bow. I can get the string contact with my nose by pushing my head down but this feels uncomfortable and an unnatural position and not one that i think is repeatable; seem to spend the time at anchor poking around with my nose until the hits the string; not going to win any prizes for good form. I could go back to a more 'side' anchor. I could try some extra long limbs. But that's a big chunk of money.

Which got me thinking about other advantages/tradeoffs of having extra long limbs and an even longer bow. Measuring the string angle at the limb tips at full draw for me and for my son sees his being smaller as his bow is relatively bigger. What's going on at the limb tip as that string angle increases? I understand that there is an increase in the rate of change of draw weight after a certain draw length but what about laterally? Would any imperfection in the limbs' alignment in the riser be magnified as that string angle at the limb tip increases? How would this manifest itself in the shot?

I'm guessing being able to get a better chin/nose contact will have a bigger effect on my shooting than any mechanical improvement and I realise spending money on longer limbs won't get me on the plane to Tokyo but i like to understand these things not least to help with my son's progress.

So bowyers, archers, mechanics all information most gratefully received! Thanks.
 

geoffretired

Supporter
Supporter
Can you please clarify something for me? I am confused where you mention the top of your thumb under your jawline.
Now you are using the top of your finger, and I am trying to imagine in what way the two are different.My immediate thought was that removing the thumb would raise your hand bringing the string up nearer to your nose. I am obviously getting the wrong pictures.

Having read your post again, can we check that I am thinking about the same angles as you. The string angle at the limb tip, gets bigger as you draw the string further back. Is that matching how you are escribing it?
 

Stretch

Well-known member
See above...it's almost impossible to guess this out without pictures and or video. You could be making a mistake in your setup and/or anchor, or it could be the shape of your face. We have no way of knowing. But most archers have to compromise to get a solid repeatable anchor. If you need a deeper side anchor due to the shape of your face you need to find additional reference points to make it consistent.

On the other hand, a 74" bow is a muckle thing and you are unlikely to get good performance (in terms of speed and sight mark) unless you are shooting 33" plus arrows. (And probably closer to 34"). Although the bow will plug every arrow in the same place if you can afford the speed loss. A low efficiency bow shot well will shoot better than the other way around :)

Stretch
 

Rog600

Member
Yes I realise a picture would be better but with glacial broadband I'll have another go with words;

Old anchor; top of my thumb under my jawline, index finger alongside my jaw underneath the fleshy part of my cheek. String contact with nose and right hand side of my chin.

New anchor; thumb tucked down and its knuckle touching my Adam's apple. Top of index finger under jawline. String contact more central on chin, no nose contact.

Better release with latter though i now realise that my improved release my have happened whilst still using the former anchor and that i shouldn't have assumed one has followed from the other!

As for the bow, my draw length is 32 1\2" to back of the riser (measuring arrow) and I'm using 32 3/4" arrows from tip of pile to bottom of nock groove.

Two angles I'm interested in; the one at the fingers which to my mind enables good chin and nose contacts if it is obtuse enough and perhaps needing a side contact with the chin if more acute. A long nose, no chin combo might be beneficial?

Other angle is the one at the limb tip. Obviously related to the one at the face and a function of overall bow length. Unrelatedly to my anchor issues, I'm interested in whether anything happens mechanically at the limb tips to the detriment of the shot at greater angles ie on bows shorter than recommended. I can understand there being an increase in arrow speed. Is there any reduction in stability, for example, or is that more dependent on limb materials etc?

Thanks for your help so far!
 

Rog600

Member
"A low efficiency bow shot well will shoot better than the other way round"

So a longer bow than I currently shoot would be lower efficiency, am I right thinking I'd sacrifice the arrow speed and therefore cast? But with an improvement in the string angle for my face/anchor, would I be shooting it better? Obvs not expecting you to answer that!!

I've a good sight mark for 70m currently that leaves plenty to go at.
 

tan.k.sun.7

New member
Yes I realise a picture would be better but with glacial broadband I'll have another go with words;

Old anchor; top of my thumb under my jawline, index finger alongside my jaw underneath the fleshy part of my cheek. String contact with nose and right hand side of my chin.

New anchor; thumb tucked down and its knuckle touching my Adam's apple. Top of index finger under jawline. String contact more central on chin, no nose contact.

Better release with latter though i now realise that my improved release my have happened whilst still using the former anchor and that i shouldn't have assumed one has followed from the other!

As for the bow, my draw length is 32 1\2" to back of the riser (measuring arrow) and I'm using 32 3/4" arrows from tip of pile to bottom of nock groove.

Two angles I'm interested in; the one at the fingers which to my mind enables good chin and nose contacts if it is obtuse enough and perhaps needing a side contact with the chin if more acute. A long nose, no chin combo might be beneficial?

Other angle is the one at the limb tip. Obviously related to the one at the face and a function of overall bow length. Unrelatedly to my anchor issues, I'm interested in whether anything happens mechanically at the limb tips to the detriment of the shot at greater angles ie on bows shorter than recommended. I can understand there being an increase in arrow speed. Is there any reduction in stability, for example, or is that more dependent on limb materials etc?

Thanks for your help so far!


I anchor mid chin same place all the time. No nose reference as east Asian face and nose would not allow it unless eyes on stalks a la snails. I draw by lining up string with sight pin and target and T draw straight back with all lines up on target. Photo 40cm target @ 18m



Sent from my iPhone using Tapatalk
 

geoffretired

Supporter
Supporter
It sounds like the first anchor had the thumb under the jaw, but the top finger was probably round the front of the chin meaning the hand and string were slightly higher than they are when the finger is more under the front/centre of the jaw.
I cannot see your anchor, but in my mind's eye it seems the newer one might be more manufactured for some reason.I have known archers change an anchor point because they were told, or they thought, the string should touch the centre of the chin. I am not sure if that applies to you or not.
To my way of thinking it is better to get the draw forearm in line with the plane of the bow. That offers the archer the chance to relax the forearm and biceps and get a relaxed release rather than a slightly plucking release caused by tensions and deliberate letting go. One thing that the anchor can provide is a string line that is in front of the aiming eye.Not dead centre in front or you can't see past it, but close enough to see it very close to the sight aperture. This is you left to right back sight. The up and down back sight is determined by where the arrow nock is in relation to your aiming eye. That is dependent on the position of the top finger, and in particular, the part of the top finger where the string exits the finger joint that is taking the contact.
Let me just run along a different track for a moment. If you could turn your head full face towards the target and drew the string to the centre of your chin and nose, you would not see the string as you look through the sight to the gold. If you look in a mirror with a piece of string held tightly in both hands as if it was a bow string, with the string touching centre of nose and chin you will see the string is mid way between your eyes. To reach a good position for the string, in relation to your aiming eye, you will have to turn slightly away from the target/mirror and eventually the nose turns away till the tip in directly under your aiming eye. You will also see that the chin has moved in the same way and the string line would probably land off to one side of the centre of the jaw. The flex in the neck allows us to position the head so the string is aligned with the aiming eye, and allows a contact on the chin, that is also below the aiming eye. Chances are, that a shorter draw, one that is stopped by the centre of the chin getting in the way, can prevent nose contact with the string.
When the string contacts the side of the jaw near the front but off centre, the draw is free to increase and nose contact happens, too. Obviously chin and nose relative positions will determine how easy that is, or how natural.
I fully understand your desire to know all about the equipment and how it works, I am just the same. We need to explore these things for ourselves and with others of like mind if relevant. BUT, when it comes to actually shooting the arrows from the bow, accuracy is about the variations we bring to the equipment and variations in posture. These can be seen to be true, in our minds. The other variation is in the execution of the shot; the way we are releasing the string and how we are drawing the bow at that time. How often are we spot on with the aim, only to hit a blue. next shot is spot on aim again and is a red, well away from the previous blue.
Sorry. I digress!
 

Rog600

Member
Yes and yes, your mind's eye is spot on.

I was working on getting my shoulders and wrist aligned when I changed anchors and it certainly felt more comfortable at full draw with the back muscles in play and just shadow-boxing it now, it seems easier to get my shoulder round with the 'under' anchor as opposed the 'side' anchor. (This could be a function of an old shoulder injury (cricket/rugby) perhaps).

As ever, Geoff, you've explained something fantastically well in much needed laymans' terms! And I'll be standing in front of the mirror later.

I think there's a middle way and if the side anchor isn't wrong and I can still get everything into line and onto my back muscles, then the fact that the string isn't centrally on my chin needn't matter?
 

geoffretired

Supporter
Supporter
I was working on getting my shoulders and wrist aligned when I changed
That is a good thing to work on. The two shoulders should be more or less aligned with the target. Having placed our feet and stood up straight, facing along the line, we turn our heads to look at the target.There can be a tendency for the shoulders and hips to turn slightly towards the target at the same time. This is more likely to happen if we are also raising the bow as we turn the head. I try to turn my head and do nothing else at that stage. Then I lift both of my arms... the bow has to play second fiddle to my arms; I want my arms to be in position. I move my arms and nothing else at that stage. Hopefully my shoulders are still aligned and then I draw with as little movement as possibly apart from the draw elbow swinging round to its full draw station. I move my draw elbow and hopefully, nothing else. I do notice the bow hand lowers during the draw, but I don't deliberately lower it ....it seems to happen as if matching the movement of my draw elbow, which swings back with a hint of downwards to get my hand under the jaw as the string arrives at my face. If I manage to swing my elbow back without getting too stressed, the biceps stay relaxed and my draw wrist follows obediently behind my draw elbow. My hand is pulled into line by the string, so the hand is always on a line between bow grip and draw elbow. That sounds like a lot of work to get right; but it isn't. The hand is pulled into line, so I have nothing to do with that. i just move the draw elbow. If you roll up a length of cord and throw it in a heap on the floor, you can pick up one end and walk backwards with that end. Soon you find the whole length is following you in a line behind you. I think of my draw forearm and the arrow as being that cord. I suppose in reality it is more like two straight rods hinged at about the middle, I pull one end and the two rods get pulled into line following the direction I pull along.
When I get this right, the draw hand lands where it lands. I don't try to make it go to a special place, I let it go where it is drawn to. When I get it right, it is the same place each time. If I get my head positioned in the same place each time, and my shoulders, the draw hand reaches the same part of my jaw with little or no adjustment.
It is all based on building a posture and the end result is dependent on the first laid brick, and all subsequent bricks. just like a lego tower. One brick at a time and in the right order.
 

Rog600

Member
Right, I'm 'working from home' today and the sun is shining so I've just stood and shot into a boss, just trying to feel what's going on. Think I've made some progress. Firstly, just to put to bed any thoughts of limbs stacking or me being overbowed, I tried an outlandish side anchor and managed to pull the string into my nose without any drama and it felt like it would go much further. So I've got that out of my head and feel like I've got somewhere.

My head is a little less turned towards the boss, my string hand more or less where I'd moved it to previously, ie under my chin, and I have the string touching, just, the left side of my nose. I have noticed two new things that may or may not be good news. The first is that to get my new head position to feel the same relative to my neck, (a position that seems to be a 'where it wants to turn to' position) I've made a more definite 'squaring up' at the hips which I'd started doing (but maybe not enough). This feels good, comfortable, and everything feels 'lighter', and feels like it has eliminated any plucking as my draw hand is being pulled round by my back at 'execution'.

However, secindly, I now can feel the string at full draw on my chest. Again, only a touch. I suppose it is because wrist-shoulder-shoulder alignment is straighter. Is this okay? From a repetition point of view, after a few ends, chin, left side nose, chest contact all started to feel familiar and I've some vanes to replace.

I felt like i was getting somewhere but inevitably I've started to get tired and I don't want tiredness to cloud the outcome of the exercise.
 

geoffretired

Supporter
Supporter
That all sounds like a step or two in the right direction. Posture is the platform from which the bow launches the arrows. If that is a weak or complicated posture, the archer has to shoot a lighter bow or struggle to control the launching process and the drawing of the string.
Head position, as regards turning towards the target, can be a vague sort of thing as there seems little to use as a reference. One thing that has helped me over the recent years has been wearing sunglasses. I need them for bright conditions, but the frame, when not too thick, just comes into view close to the left side of my sight ring when I shoot. Glasses with no lenses might help.
Squaring the hips has probably had a knock on effect higher upi the body, bringing the shoulders into line with them. One thing you can try; just to highlight the difference, is standing facing the target, feet side by side on the shooting line. Now when you draw you will really feel the draw weigh getting it your way and the draw forearm has no chance of getting into line. I would try that by drawing slowly so that as the weight increases you can abort the draw before you feel too uncomfortable.
As you have found, when the shoulders are in better alignment, the last inch or so of the draw feels easier, and that has to help with maintaining the draw effort.
When the string touches the chest, it can be because of the massive chest the archer brings with him or her. I am built like a snake and don't really suffer from string contact. However, I did make a similar change to the one you have been making, and string contact happened as did banging my bow arm with the string on release. Two things might be working there. One is that you might be standing too far round away from the target makng the bow shoulder swing into the path of the string and bringing the chest into contact, too. Another reason could be the shape of the spine, that you make when you stand up straight. Sometimes when we stand up straight, for archery, we get an arching of the lower back and with that comes a raising of the breast bone. It looks a bit like " chin up and take a deep breath". Quite often when we stand like that, the shoulders go back and that brings the chest even further forward compared to the bow arm. It is worth standing up with the bow arm out and just experiment with standing up straight to see where the bits move to.
We don't want to feel the lower back arching; we don't want to feel the chest rising. We are not trying to slump and look hunched; it's more like a leaning forward at the waist.
Contact with the chest can be a problem. If you wear different tops from day to day, the change of material can have different effects on the string as it sets off. Also, if extra clothes are worn in bad weather, things get worse. A chest guard does give the same surface to contact if there is any and often the chest guard can pull the clothing away from the string contact, and problem solved.Very light contact is not so bad as the string moves away from the clothing as it sets off,rather than brushing along the fabric creating a bow wave in front of the string.
 

Stretch

Well-known member
All I was saying is that if a bow 2" longer than normally recognised as "best" for your drawlength feels better or allows more consistency and natural head position then it won't kill you if you execute the shot better. In fact comfort is a major factor. All the recommendations do is set a line in the sand for good bow efficiency (conversion of stored energy to arrow velocity) vs "forgiveness". In the old days you'd probably find the limbs would stack if you went more than half an inch over. Nowadays a Medium limb will feel ok at 31" (on a top limb).

I seem to recall Petra Ericsson shooting a 68" despite her 25" (? Memory not so good) draw. She made her results do the talking. But it was a Nishizawa... so probably still faster than most 64" bows of the time.

So it won't make a huge difference if you're only shooting 70m and are comfortable with current sight position. Typically you'd only notice at 90m where the 2" extra limb could be the difference between sight all the way out and a few notches in. I think my 70" F4 limbs were 3 fps faster than my 72" at the same drawlength,weight and arrow. (Might have been 5fps but it wasn't a major factor in the decision)

Stretch
 
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