# Tiller and Nocking Point



## HikerDave (Jan 1, 2011)

Bob Furman said:


> I have been playing with my Tiller/Brace-height this last week and although I'm pretty happy with the tuning I was a bit concerned that my nocking point was 1/2" above 0. I was trying to recall what effect your tiller played on your nocking point? I have been running my tiller about 3/16" positive as recommended by Hot, but was thinking of seeing how it acted at 0 offset and seeing if that might bring my nocking point down a bit?
> 
> 
> What do you all think?


I'm curious to know, too. Kari Jill Granville suggested that we could get a better bare shaft tune on my daughter's bow by adjusting tiller but I ended up moving the nocking point up instead when I made the next string. So I guess there is a school of thought that recommends tuning with tiller.


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## dchan (Jun 29, 2004)

Bob Furman said:


> I have been playing with my Tiller/Brace-height this last week and although I'm pretty happy with the tuning I was a bit concerned that my nocking point was 1/2" above 0. I was trying to recall what effect your tiller played on your nocking point? I have been running my tiller about 3/16" positive as recommended by Hot, but was thinking of seeing how it acted at 0 offset and seeing if that might bring my nocking point down a bit?
> 
> 
> What do you all think?


So this is where paper testing is very helpful but lets look at the physics of this.

Ideal brace height depends on the shooter. This is why shooting for the quiet sweet spot would change for each shooter. Our ideal here is to have the arrow nock release from the string when it is moving straight towards the target and in a neutral state (between bends as it clears the riser) 

Ideal nock level would have the arrow release from the string when the string slows down and the arrow is 90 degrees to the string. Maximum transfer of energy and not pushing the nock end up or down.. So nock level, while a general start point is 3/16" can vary depending on arrow diameter and how clean we keep our fingers off the arrow.

Ideal tiller is to have both the upper and lower limb working the same amount through out the shot. Again for maximum energy transfer and to not push the nock end up or down. Positive tiller is usually based on the fact that most of us shoot with one finger above, 2 below the arrow meaning we are going to be pulling the lower limb a little more than the upper one. Mfg calculate this into their designs as well but technically a string walker or 3 under shooter might need to have a different tiller.

So you can see the two things you are looking (actually 3 things) at are all dependant on the shooter (you), each other, your style and equipment. We start with some recommendations just to get you in the ballpark but there are no absolutes. As you get better, make slight changes in gear, change vanes and fletches or nocks these things will change. This is why as coaches its good to teach understanding on what things do what. Where the gains are and what things make sense to pursue, and what things might not have much ROI.

So back to your question. Following the tuning for tens document or eastons tuning guide, make slight adjustments (one at a time) and see what affect they have. Where your setup is may be right on (from what i read in your post, its not far off) or may be helped. Tuning for tens and easton both have a sequence you should follow their order but other than that, enjoy the journey.


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## dchan (Jun 29, 2004)

HikerDave said:


> I'm curious to know, too. Kari Jill Granville suggested that we could get a better bare shaft tune on my daughter's bow by adjusting tiller but I ended up moving the nocking point up instead when I made the next string. So I guess there is a school of thought that recommends tuning with tiller.


Since I haven't seenyour daugher shoot I can only guess what her coach might have seen but if she (like lots of kids do starting out do) is shooting 3 fingers under, a tiller adjustment may make more sense than a nock move. Or sometimes we see a bow where the limbs are just not balanced due to a mfg difference or the fact that the child has a short draw and the limbs might have different draw curves when not close to their rated draw length.

Again as stated above, lots of variables.


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## Bob Furman (May 16, 2012)

In relation to my post http://www.archerytalk.com/vb/showthread.php?t=1777972 where my Tiller changed overnight from being 3/16" postive to about 3/8" negative I did notice that my nocking point now had moved up. Just a rough guess, but I suspect it moved up about 1/4". So by going to a more negative tiller it appears that your nocking point raises. Maybe one of you Rocket Scientists have a way to calculate that ased on the limb angle and tiller change?


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## Greysides (Jun 10, 2009)

Bob Furman said:


> In relation to my post http://www.archerytalk.com/vb/showthread.php?t=1777972 where my Tiller changed overnight from being 3/16" postive to about 3/8" negative I did notice that my nocking point now had moved up. Just a rough guess, but I suspect it moved up about 1/4". So by going to a more negative tiller it appears that your nocking point raises. Maybe one of you Rocket Scientists have a way to calculate that ased on the limb angle and tiller change?


This bit. at least, is easy to explain.

3/16" positive is a measurement that tells us the lower limb is set stronger than the upper. 

(Increase preload/turn in the upper limb bolt and the limb straightens in the riser pocket, more into line with the riser, and becomes harder to pull- the limb tip starts further away from you.)

3/8" negative tells us the upper limb is stronger than the lower.

So, overnight, the stronger limb has changed from being the lower to the upper. The balance of power has shifted. The upper limb is now pulling harder on the nock than before and has pulled it away from the lower limb, therefore upwards.


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## HikerDave (Jan 1, 2011)

dchan said:


> Since I haven't seenyour daugher shoot I can only guess what her coach might have seen but if she (like lots of kids do starting out do) is shooting 3 fingers under, a tiller adjustment may make more sense than a nock move. Or sometimes we see a bow where the limbs are just not balanced due to a mfg difference or the fact that the child has a short draw and the limbs might have different draw curves when not close to their rated draw length.
> 
> Again as stated above, lots of variables.


Moving the nocking point up about a little over 1/16 inch to 5/16 inch was enough to correct the tune. So I'm talking about a pretty fine adjustment here.

We haven't tried experimenting with tiller -- I've just gone with Gary Yamaguchi's 4mm recommendation.

Right now she has a perfect bare shaft tune with high-quality arrows and a very quiet bow.

I'm getting a new set of Carbon One's for my new bow and then I'll play with tiller effect on bare shaft placement when I tune my own bow. (My daughter doesn't really like me even touching her bow but her desire to shoot well can sometimes overcome her dislike for equipment changes.)


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## Greysides (Jun 10, 2009)

Here is a quote about tiller pertaining to setting up a barebow. However, the logic is the same.



> First I set up my bow with a fairly low nock point, say 1/8" to 1/4" and shoot a group of bare shafts and fletched arrows into a bale. If the bare shafts group just slightly low, then I start creeping the nock point down. If the BS group is high, then creep the nock point up. If the group spacing is over 5", let's say, then I would leave the nock point alone and adjust the tiller slightly.* ADJUSTING THE TILLER TO A MORE NEGATIVE STATE WILL RAISE THE BARESHAFT GROUP*, going more positive will lower it. Since you are adjusting the difference between the limbs, you can either adjust one bolt or both (in opposite directions).


It shows the relationship between NH and tiller. The other variable in the mix, not yet mentioned is grip type (low/medium/high). This affects NH and tiller tuning too.


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## dchan (Jun 29, 2004)

After watching enough shooting on the line, with an eye out for "anomalies" you start to see things. Someone shooting with the nock a little higher or lower than it should be looks pretty odd. Poor tiller adjustment does too. The more you watch, the more you see. 

Often from across the field I'll see something strange and I'll go by and take a closer look. 1/16th" can look a little strange if they are already on the edge of norm. We grab the bow square to confirm and then watch arrow flight to see if it's OK. Sometimes it's fine, sometimes a correction makes a big difference. 

Tiller of 1/8" shows up too. So again your coach might have seen something and just made a suggestion. Your solution might have brought it in to tune. With the human factor added in (How do we shoot) it can be a guess. If it worked, I would say leave it alone.

Fatigue from a full day of shooting along with an inconsistent grip can affect how tiller changes tune too (along with Greysides comment about grip type) Its funny how just a little more heel pressure in the grip will cause high arrows on my bow but low arrows on a different bow. We can tune out the error as long as we are consistent with the error. ie always "heel the bow" can be fixed with a tuning change or it can be fixed with more practice focused on keeping the pressure even. Even pressure is less tiring but habits are hard to change so sometimes it makes sense to just change the gear to get the same result.


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## dchan (Jun 29, 2004)

HikerDave said:


> Moving the nocking point up about a little over 1/16 inch to 5/16 inch was enough to correct the tune. So I'm talking about a pretty fine adjustment here.
> 
> We haven't tried experimenting with tiller -- I've just gone with Gary Yamaguchi's 4mm recommendation.
> 
> ...


It's great that the move fixed her tune.

FYI 1/16" is actually a pretty gross adjustment not very fine at all. If she is shooting a 16xx arrow that's almost 1/4th the diameter of that arrow or a change of 25% of the arrow shaft size. If it's a smaller shaft then it's even a higher percentage of the arrow shaft.

For those of us using tie on nocks, where we turn the nock (like a screw) up or down the string, 1/8 of a turn is what I would consider a fine adjustment. on average strings 1 full turn would be less than 1/16" 

But it worked and I'm glad it did.

DC


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## HikerDave (Jan 1, 2011)

dchan said:


> It's great that the move fixed her tune.
> 
> FYI 1/16" is actually a pretty gross adjustment not very fine at all. If she is shooting a 16xx arrow that's almost 1/4th the diameter of that arrow or a change of 25% of the arrow shaft size. If it's a smaller shaft then it's even a higher percentage of the arrow shaft.
> 
> ...


I had no idea that nocking point was so sensitive. Thanks for the tip!


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## dchan (Jun 29, 2004)

HikerDave said:


> I had no idea that nocking point was so sensitive. Thanks for the tip!


It isn't always but I am just saying it can be. 

If it's a beginning or intermediate archer, It sounds like you are doing it correctly. It's just that it can get real touchy. The better the archer, the more it makes a difference. (or the better the ROI)


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