James Park tuning method issues

tak160

New member
Hey all, after fitting a new beiter nocking point onto my string (some of you may have seen my other thread on it :p), I thought it best to retune my bow. I use to tune using Simon Needham's method but I thought I might give James Park's method a go seeing as people say it's quick and easy. So I went and shot at 20 yards to tune my bow using his method. It was indeed quick and easy and my bareshafts were within or just to the right of my groups (by about an inch), so I left the poundage as it was and went on to change the centre shot and pressure of the button until the arrows hit centre. It was indeed very quick and easy and I thought it was completely tuned (for my level).

I then went on to shoot at a 60 yard boss to work on my form briefly, but I noticed my arrows were in a good horizontal line on the boss but spread across the boss spanning as far out as the blue from one side to the other. This was fair enough, seeing that on average, they were flying towards the centre, I put it down to a possible poor release, bow torque, bad hand position etc.

I then shot at a 50 yard boss, but the arrows kept landing to the right of the boss in a group which I found quite puzzling seeing as at 20 and 60 yards they were going towards the centre (on average at 60 yards anyway).

Finally at the end of the night, I decided to test the tune of my bow using a couple of bareshafts at the 20 yard boss again. The fletched arrows were going to the centre of the boss as they should...but the bareshafts landed a good 3-4 inches from the centre, which means my arrows are too whippy.

Could the weak arrows be a cause of the arrows appearing to go to the right at 50 yards? And is this suppose to happen with the James Park method (the apparent weak shaft I mean)? Should I try and retune it again?
My arrows are actually a spine out for my bow (42 lbs with 710 navs) but seeing as the bareshafts didn't land too far off during the tuning, I thought I would leave it at that poundage, although I have been shooting for a few months now at this poundage and the arrows seemed to tune ok even with Simon Needham's method.
 


john heff

New member
<snipit> so I left the poundage as it was and went on to change the centre shot and pressure of the button until the arrows hit centre.
This is not the James Park method. You MUST get the bareshafts to group with the fletched shafts using a STIFF plunger and adjusting the draw-weight....NOT by adjusting the pressure button.

Could the weak arrows be a cause of the arrows appearing to go to the right at 50 yards?
Yes
And is this suppose to happen with the James Park method (the apparent weak shaft I mean)?
If you follow the method as written your arrows should hit center at both short and long distance.

Should I try and retune it again? My arrows are actually a spine out for my bow (42 lbs with 710 navs) but seeing as the bareshafts didn't land too far off during the tuning, I thought I would leave it at that poundage,
You should retune following the exact instructions. If you vary from his instructions you will get various results.

<although I have been shooting for a few months now at this poundage and the arrows seemed to tune ok even with Simon Needham's method.
If Simon's method works ok for you then you may want to stick with it. James Park method is fairly quick and works very well if you follow the instructions. - John
 


tak160

New member
This is not the James Park method. You MUST get the bareshafts to group with the fletched shafts using a STIFF plunger and adjusting the draw-weight....NOT by adjusting the pressure button.

I did use a stiff plunger to get the bareshaft to group with the fletched arrows. The moving of the centreshot and pressure of the button was done afterwards to get the fletched arrows to group into the centre. I think I did follow the instructions but just in case, I'll give an overview of what I did and you can check.

-Centreshot placed dead centre with stiff plunger in place.
-Shoot 5-6 fletched arrows with 2 bareshafts in random order at 20 yards.
-Adjust nocking point to bring bareshafts level with fletched arrows.
-Adjust draw weight to get bareshafts into group (if arrows too stiff or to weak).
-Once bareshafts impact within group, set the sight so that arrows impact the centre of target.
-Adjust centre shot to the left of centre (RH archer) and then set the pressure button to medium tension.
-Shoot the fletched arrows and adjust either the centre shot or the pressure button accordingly until the arrows hit centre again. I chose to readjust the pressure button.

These were the steps I took. Are they right?
I also have problems with my bracing height. It seems to change as I shoot but it only drops by 1/16 of an inch so hopefully it doesn't make too much of a difference, although apparently no-one else has this problem :s. It could well be a contibuting factor to my problems though.
 


john heff

New member
I must have misread your first post....it appeared as though you had the bareshaft shooting a couple inches to the weak side and brought it in with the button pressure instead of the draw-weight limb bolts. I apologize for jumping to that conclusion. It can be confusing when several similar steps are involved and the author refers to one but the reader interpretes another. My Bad!
I did use a stiff plunger to get the bareshaft to group with the fletched arrows. The moving of the centreshot and pressure of the button was done afterwards to get the fletched arrows to group into the centre. I think I did follow the instructions but just in case, I'll give an overview of what I did and you can check.
-Centreshot placed dead centre with stiff plunger in place.
-Shoot 5-6 fletched arrows with 2 bareshafts in random order at 20 yards.
-Adjust nocking point to bring bareshafts level with fletched arrows.
-Adjust draw weight to get bareshafts into group (if arrows too stiff or to weak. Might I add: -"Marginally")
-Once bareshafts impact within group, set the sight so that arrows impact the centre of target.
-Adjust centre shot to the left of centre (RH archer) and then replace spring and set the pressure button to medium tension.
-Shoot the fletched arrows and adjust either the centre shot or the pressure button accordingly until the arrows hit centre again. I chose to readjust the pressure button.

These were the steps I took. Are they right?
Yes, those are the correct actions and order which to take them. Once you've adjusted the sight to get the arrows hitting the center of the target you don't adjust the windage again (during tuning process), you adjust the button tension or pressure, which is what you did. If those steps are followed to the letter they should give good results. Maybe someone else will have better suggestions. - John
 


geoffretired

Supporter
Supporter
When you follow James Park's method, to the letter, it says that you should take out the match that held it rigid, and set the pressure to something nice. I suppose that is a bit like saying softer than rigid but not sloppy.
Then you set centre shot so the arrow points slightly away from the sight window.( a little left for right handed archers)
Then you start shooting arrows again at 20 ish to see where they land. If they do not land in the centre, you adjust the centreshot position, not the spring tension.
I also feel, that the bare shafts and fletched shafts should have been made to land together by changing bow weight, rather than leaving them nearly together.
 


tak160

New member
When you follow James Park's method, to the letter, it says that you should take out the match that held it rigid, and set the pressure to something nice. I suppose that is a bit like saying softer than rigid but not sloppy.
Then you set centre shot so the arrow points slightly away from the sight window.( a little left for right handed archers)
Then you start shooting arrows again at 20 ish to see where they land. If they do not land in the centre, you adjust the centreshot position, not the spring tension.
I also feel, that the bare shafts and fletched shafts should have been made to land together by changing bow weight, rather than leaving them nearly together.
No worries John. Maybe I should have explained a bit clearer (although that probably means writing a bit more and that first post was already quite wordy).

I actually set the pressure button to somewhere near what I originally had and then set the centre shot. His book which I obtained (albeit by accident) says changing the pressure on the button was an alternative and I thought that would be a bit easier than changing the centre shot. But I think you are right that I should have reduced the poundage to get the bareshafts land within the fletched arrows.

I was thinking of changing my piles from my current 120 grns to the 100 grns I originally got with the arrows. That will probably stiffen the arrows up but what are the disadvantages of this? Will it noticably adversely affect my groups at long distances due to a lighter point?
 


geoffretired

Supporter
Supporter
If you fit lighter piles, the arrows perform stiffer.But the bow also shoots faster as the total arrow weight is less.Quite often the slightly stiffer arrow(apparent stiffness) is compensated for by the extra speed and the two can cancel each other out and you end up where you started.
From what I've been reading recently, top archers try different piles to see if one weight gives tighter groups, but not to get a better match to the bow; their arrows were already matched.
 


tak160

New member
If you fit lighter piles, the arrows perform stiffer.But the bow also shoots faster as the total arrow weight is less.Quite often the slightly stiffer arrow(apparent stiffness) is compensated for by the extra speed and the two can cancel each other out and you end up where you started.
From what I've been reading recently, top archers try different piles to see if one weight gives tighter groups, but not to get a better match to the bow; their arrows were already matched.
That's a really good point. I've never thought about that. Thanks. I think I'll reduce the poundage for the time being. Hopefully my sight marks won't fall significantly. I'll probably experiment with the piles later on in the future to see whether it can improve my sight marks though, seeing as I have a whole set of 100grns at my disposal.

There's also another issue I've got. I've always set my bracing height to 9 inches (68 inch bow) because it's easy to remember and it's about half way between the recomended range in the hoyt bow manual. Most tuning guides recomend having the bracing height between the recomended ranges. However, when I'm shooting, apparently my bow sounds like the bracing height is too low and there's a load noise coming from the bow. The hoyt manual says I should measure the bracing height from the pivot of the grip which is what I've been doing since getting my hoyt riser. However, the way I use to measure the bracing height was to measure to the centre of the pressure button. I did that today and found that the bracing height measured to the button is shorter than the measurement from the pivot of the grip and so would be on the low end of the recomended range explaining the noise. Do I take the bracing height measurement from the grip or to the pressure button?
 


geoffretired

Supporter
Supporter
As far as measuring BH is concerned, it just needs to be the same place each time to make sure it is the same as last time you used the bow.
Measruing from the button would alter the number you would have to rememeber but would make no difference to the bow, unless you twisted or untwisted the string.
The range is a sort of safe range; being in the middle when you start means you can go either way when you are experimenting to find the best BH for you and your bow/arrows.Try changing a little and see if it gets better or worse. Go the opposite way if necessary.
Some will tell you that the sound doesn't win you points;so go by the groups you get.
 


tak160

New member
As far as measuring BH is concerned, it just needs to be the same place each time to make sure it is the same as last time you used the bow.
Measruing from the button would alter the number you would have to rememeber but would make no difference to the bow, unless you twisted or untwisted the string.
The range is a sort of safe range; being in the middle when you start means you can go either way when you are experimenting to find the best BH for you and your bow/arrows.Try changing a little and see if it gets better or worse. Go the opposite way if necessary.
Some will tell you that the sound doesn't win you points;so go by the groups you get.
I've always measured my bracing height every time I set my bow up. Mainly after a couple of arrows to let the string set in becuase it's usually about 1/8th of an inch or so too high at the beginning and then drops down to about 9.
I've been told in the past to keep my bracing height as it is and just shoot which is what I've done for a couple of months now. Would altering the bracing height really make much of a noticable difference in groups? And wouldn't the bow be out of tune every time you changed the height, which might also increase the size of the groups?
 


geoffretired

Supporter
Supporter
If you start experimenting with BH to see if it gets quieter, or to see if the group size changes, then it's a good idea to keep checking the tune to see what happens to the bare shafts and fletched ones at 20y.
You may find that the bare shafts close in on the fletched ones; you may also find that the groups are on centre at all distances, and your original problem is sorted.
Things may work the other way and you could find that things are best where they are at present.
If you don't change anything you will never find out, but that's a decision you make for yourself. I would have to find out, but that's the way I am.
If you decide to try a change of BH and also to check what happens to the bare shafts at 20y etc. then I would advise you to make a written note of each cahnge you make as you make it so that everything can be put back to where it is now should things go pear shaped.
For example; 20 extra twists= +1/8" on BH = bare shaft 1" further right.
or 20 extra twists= +1/8" on BH = bare shaft 1" low = move nocking point down 1/16"
Those numbers are just guesses so expect your results to be different.
The notes are a safety net. You may have to stop for some reason before you get to a stage where you say things are so good you will leave them as they are. Your notes can help when you go back and continue from where you left off.
 


tak160

New member
Cool, thanks geoffretired. You have been a massive help! Much appreciated.
I'm an addicted tinkerer so I think I might have to try it soon and vary the BH as you say. I did want to try and find that perfect BH a while ago but there was an overwhelming majority who advised I leave the bracing height as it was and just work on form. I might do it after my last competition though just in case I screw up somehow.

In terms of the tuning, should I try and retune it after each change of BH or leave the tuning as it is throughout? I've read somewhere that the BH changes the position where the nock detaches from the string and since the string's oscillating, it's going to change the direction of the bareshaft depending on the phase of the oscillation, but I'm not sure whether it makes a noticable difference.
 


geoffretired

Supporter
Supporter
There is no substitue for trying to improve your form; that is what brings higher scores.
However it is worth setting aside some time for tuning or you may lose some point through having a tuning problem. Those lost points will carry on as you improve but they could be reduced with an hour or so tuning.
If you make a small change to BH you may see no changes, but there could be unseen changes and checking with bare shafts and fletched ones could show up a change that needs acting upon. For example, you may need to move nocking point.If the bare shafts moved left or right of the group, you could change bow weight to bring things back together. If you record the changes as you go, you can go back to the start or even back one step at a time.
If you make a large change to BH you will probably need to change nocking point and bow weight and you may see changes in arrow flight or hear the difference in the noise level.
If you make changes to bh and do not check with bare shafts, you could be starting new tuning problems that you don't know about, so the rest of the bh experiments could be upset by that.
What shows up as you make these changes has to depend on the quailty of your shooting. If an archer is scattering arrows all over the red/gold at 20y, then a small change in bh will hardly show as a change in the arrow landing pattern. If another archer can shoot very tight groups at 20y, then he/she can see if one group is separate from the other by as little as an inch or two.
I would go to your competition and shoot the best you can. Do the experiments after that and find out for yourself what happens when you make these various changes. Then keep a healthy balance between improving form and re tuning. Often, a change of form can require a change of tune; increase in draw length for example.
Enjoy the competition.
 


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