Setting up pressure button and sight pins

[Newalpost]

I'm still relatively new to archery but enjoying both the physical and technical challenges it presents. I started with a Cartel cheapy pressure button which came with a couple of springs and I just used the one that was already in it. I set up my centre shot and offset the arrow tip but didn't actually setup my sight pin position to any formula, just tweaking it until I had a reasonable group. The tension on the pressure button spring was set about mid-point and left there.

Now I've started to get a little more serious and having been going through the Tuning For Tens procedure, although I skipped the paper test and went to section 5. At the same time I switched to a Shibuya Pressure button.

I've now noticed that there was significant difference in the position of my sight pin when setup using the method in 1F - that is the arrow is centred on the string (not offset) and the pressure button has a stiff plunger - compared to what I previously had. With the Cartel button and my unscientific setup my sight pin was close to the riser, now the sight pin is a a lot further out from the riser.

I offset the arrow as described and then adjusted the pressure on the button to bring the group back to the centre and so far all seems well - at least as far as I can tell.

My questions are two fold.

1. Is there any significance to the fact that my sight pin is now a lot further out - more than 3.5cm than previous - and much more than my colleagues setup? Or is it just that I never got my first setup right?

2. Given that the Shibuya has 3 springs of apparently different tension, which one should I choose?

For what its worth I have a 30lb, 68" bow with 29" 630 spine arrows.

Thxs
Colin

 

[dgmultimedia]

First thing I would look at is a Bare Shaft test - this should tell you which way the arrow spine is out - I suspect from the stats you have given they are too stiff. But at your early level as long as you can get reasonable groups and a walk back test gives you consistent L/R placement don't worry too much - keep practicing until you feel that your groups at distance 20+ are not as good as you think they should be - then you can progress with finer tuning.


Sent from my iPhone using Tapatalk

 

[backinblack]

Hi Colin,

Yes. You would normally expect the sight pin to be close to the line of the string so, if you are saying that it's 3.5cm away from this then it sounds like quite a chunk. Alternatively, if it is now in line with the string then all is good and the process has worked.

If it's the first case, when you did the stiff button part of the tune did you align the sight pin with the string and did you then go through the process of shooting bareshaft and fletched arrows and adjusting draw weight until they grouped together before setting centre shot and putting the spring back in the plunger and adjusting it until the group moved to around the centre of the target?

Normally where arrows are matched to a bow spine wise, the sight pin is close to being in line with the string and variations around medium spring set to medium tension tend to work. This is because the arrow leaves the bow (relatively) straight and there is no need to use an extreme button setting to compensate for an arrow that is not doing so.

For what it's worth, I've never got on with the stiff button tuning method as it always throws up anomalies such as this with me (that might be me though).

 

[backinblack]

A little more, for what it's worth Archer's Advantage is saying that an ideally spined arrow for a set up with a 30lb draw weight with a 29 inch shaft would be a 750 spine so it may be that your arrows are on the stiff side...

 

[Newalpost]

Thanks for the replies....

dgmultimedia
First thing I would look at is a Bare Shaft test - this should tell you which way the arrow spine is out - I suspect from the stats you have given they are too stiff. But at your early level as long as you can get reasonable groups and a walk back test gives you consistent L/R placement don't worry too much - keep practicing until you feel that your groups at distance 20+ are not as good as you think they should be - then you can progress with finer tuning.

I've never tried a Bare Shaft test - too mean to sacrifice a couple of arrows for this However, at 20 and 30yds the arrows go in straight and I can often get 4/5 out of 6 in the gold. Sometimes I get the odd couple go astray but I'm putting this down to me, the wind, midges and position of the moon

backinblack
If it's the first case, when you did the stiff button part of the tune did you align the sight pin with the string and did you then go through the process of shooting bareshaft and fletched arrows and adjusting draw weight until they grouped together before setting centre shot and putting the spring back in the plunger and adjusting it until the group moved to around the centre of the target?

With the stiff button I did not align the sight pin with the string. The TFT document suggests that with the stiff button and arrow in a straight line (not offset), adjust the sight pin to centre the group shooting fletched arrows. It was at this stage that I noticed the sight pin had to move a lot further out than before. Aligning the sight pin with the string doesn't make sense to me because you need more than one point of reference to get a line to the target. I.E I could line the sight pin up with the string at any point from close to far away from the riser. Some suggestions indicate aligning the sight pin to be above the arrow tip.

As a point of interest the 'string picture' where I am now is such that the string is visible through the centre of the limbs and riser but the sight pin is much further out.

A little more, for what it's worth Archer's Advantage is saying that an ideally spined arrow for a set up with a 30lb draw weight with a 29 inch shaft would be a 750 spine so it may be that your arrows are on the stiff side...

For lack of any other information I used the Easton Chart and for the Easton Inspire Arrows I chose, I should use either a 750 or 630. I just went for the 630.

I've now got a few more of the Easton Inspire arrows so I think a Bare Shaft test may be called for and yet another round of tuning.

Once again thanks

 

[backinblack]

Hi Colin,

There's quite a difference between a 750 and a 630 spine in practical terms: a full spine normally covers an 8lb window in terms of draw weight. FWIW Archer's Advantage reckons that 36.5 - 37lbs would be a perfect match for an Inspire arrow of 29 inches.

The aligning the sight pin with the string thing isn't about your string picture so much as getting the arrows coming out of the bow straight (it can be changed later if you prefer), and this is essentially the reason why people tune a bow. All other things being equal, an arrow that is too stiff for the bow's draw weight will strike left of the gold and one that is too weak to the right of the gold for a right handed archer. The pressure button isn't really meant to compensate for this amount of variation as it's a fine to micro tuning tool rather than for macro tuning.

That the pin is off to the left means that with your string alignment down the centre of the limbs/ riser, the bow and arrow is pointing left to hit a target that is straight ahead of you and this is normally thought of as being sub-optimal in terms of arrow flight and having a forgiving set up.

By missing out the bit in TFT that shoots the bareshaft through paper and adjusts the draw weight to minimise the left-right tear, you have skipped a crucial part of the process as it is this that sets the bow's draw weight to match the arrow spine and without this basic set up, any further tuning is pretty much a waste of time. Sorry, I'm not trying to be mean here, but most tuning methods list this as vital before anything further can be done.

All this said, if you're hitting the middle of the target consistently with this set up then there's no real problem and it is one that will be reduced or go away if you plan to up your draw weight over time. The only issues you may have are with the arrow contacting the rest/ button on poorer releases and having to alter your sight's windage on a change of distance.

 

[geoffretired]

The bow should be set up initially by looking at it from behind, so the string appears down the centre of the limbs... top and bottom. At full draw and on aim, we would like to see the string blur appearing down the centre of the limbs, too, as that would mean the bow is facing directly to the centre of the target.
If we now put a sight on, it could be positioned so it is just off the string line to the left. Then at full draw and on aim, we hope to see the sight just to the left of the string blur... meaning the bow is facing directly to the target again. So, by seeing the string blur beside the sight, at rest and at full draw, we know the bow is facing the right way and we don't need to take our eyes off the gold to be sure.
If you have a button and set it so the arrow is a bit left of the string when looking at the bow so the string is down the middle of the limbs, you might notice the arrow appears directly below the sight when the string is down the middle of the limbs (or beside the sight.)
With a fairly stiff button and well matched arrows, they should fly directly ahead so the sight will not need to be moved. If they do not go ahead but to the left, they are stiff and the sight needs bringing out away from the sight window.
By shooting bare shafts and getting them to land beside the fletched ones, using
the set up just described, should work with very little change to the sight or the button.

 

[Newalpost]

Thanks again and no need to apologise about any advice contrary to what I've been doing. I'm beginning to see the picture here and need some time and fair weather to run the setup from the start including all steps.

As a point of interest, about how much change in draw weight can limbs/riser be adjusted? Nominally mine are 30lb but I believe that by adjusting the tiller bolts this can be increased or decreased.


Thxs

 

[Rik]

Thanks again and no need to apologise about any advice contrary to what I've been doing. I'm beginning to see the picture here and need some time and fair weather to run the setup from the start including all steps.

As a point of interest, about how much change in draw weight can limbs/riser be adjusted? Nominally mine are 30lb but I believe that by adjusting the tiller bolts this can be increased or decreased.


Thxs

Can of worms...
It depends on the handle and limbs you have. If you have handle and limbs of the same make and you're drawing 28 inches ( i.e. 26.25 to the button), you ought to be getting somwhere between 29 nad 31 pounds at some point in the adjustment range... But sometimes the marking is wrong...
Every inch longer than that you draw would put the weight up a bit. 5% of the draw weight as a rule of thumb. Then, the adjustment range of a lot of handles is nominally 10% from the bottom to the top of the draw range.

So someone drawing 30" with "30lb" limbs which are marked as measured at the bottom end of the draw range, with the limbs wound all the way up, could conceivably end up holding 37lbs... Or 35lbs. Plus or minus a pound or so, if the limbs/handle are different makes. Or lower if the limbs are Hoyt...

 

[dvd8n]

It really is false economy not to have bare shafts to do a bare shaft test with.

You need to get past that way of thinking.

I don't have a set of arrows in my possession that I haven't kept a couple of unfletched.

If you don't want to strip a couple of your set then buy a couple more without fletches.

They are incredibly revealing as to your true arrow flight.

If you want, think of them as spares that you can fletch later when you inevitably damage an arrow.

 

[Whitehart]

It is not a good idea to have dedicated bareshafts from new as over time the arrows you use regularly will change over time and the rarely shot bareshafts will behave differently to the rest of your arrows.

Always best to make bareshafts from arrows you use all the time and know they group well.

 

[dvd8n]

Do you think that's true?

I've heard people say it and also heard people swear that it's an archery myth.

I've always been in the second camp although it may be that I've never shot enough to observe it

 

[geoffretired]

I think it makes sense to say new bare shafts might not be such a good match to old fletched ones of the same spine etc. If using them causes changes, they will change more as they are used more. I think the question is, as arrows get older, does each one change in different ways, so they group less well than before?Perhaps its different kinds of damage, some of which goes undetected, that makes them less consistenr.
Does this lead on to thinking that older arrows are not worth testing for spine match using bareshafts, even if the bareshafts have been shot the same amount as the fletched ones?

 

[backinblack]

I guess it depends on how much you shoot your normal arrows versus the dedicated bareshafts, but I don't take the chance and rotate them when I refletch.

Obviously, I shoot far too badly for any observable difference but it's one less thing to worry about.:beer::beer:

 

[Newalpost]

Interesting discussion and helpful. Of course I keep coming back to the thought that my colleagues with Longbows and Flatbows or Bare Recurve don't worry about any of this and yet many of them still shoot better than me.

 

[Whitehart]

Interesting discussion and helpful. Of course I keep coming back to the thought that my colleagues with Longbows and Flatbows or Bare Recurve don't worry about any of this and yet many of them still shoot better than me.

The good ones do

 

[dgmultimedia]

Interesting discussion and helpful. Of course I keep coming back to the thought that my colleagues with Longbows and Flatbows or Bare Recurve don't worry about any of this and yet many of them still shoot better than me.

It might seem like they don't but bow and arrow tuning can become an instinctive process when you have enough experience.

At the start it's viewed as a precise mechanical process but there are so many variables and ways to tune that it becomes more a matter of personal preference.


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[geoffretired]

I think that archers take up archery for very different reasons. Some want to shoot and chat to friends. Others want to do more, including competing and finding out what they can about getting better and getting the most from their gear and efforts.
After an initial setting up. following the guidelines, some archers find they are happy enough and leave it at that. others find their arrows are coming out a bit funny and want to sort it. generally, they ask what is going wrong and are told about a form issue or told about "tuning".
These days the first step seems to be the bareshaft testing as it shows what the arrows are doing before the fletchings have a chance to cloud the issue.Some archers use their experience and possibly some trial and error to avoid taking fletchings off.Others want to know for themselves what is going on and the bareshaft test is about the best one for that.
Just finding out that the nocking point could be in a better position, can be a real plus for the newer archer. Confirming that the arrows are too stiff/weak and it's not just their bad shooting, can be an even bigger plus; even if new arrows are going to be needed.

 

[Rik]

Do you think that's true?

I've heard people say it and also heard people swear that it's an archery myth.

I've always been in the second camp although it may be that I've never shot enough to observe it

I've observed it with carbon shafts. The ones shot more end up lighter (measurably) over time. I had a set I set up and one never got shot because it was a grain or so heavier than the others. After a couple of years, I weighed the whole set again, just out of interest, and found that not only had the shot arrows lost weight, but also that the weight range within the shot shafts had increased (probably due to uneven use). The unshot shaft hadn't changed.
Was that difference measurable in results? Not by me

Anecdotally, an engineering oriented acquaintance of mine recalled measuring an extremely well shot set of ali shafts and found that they had become oval in cross section over time. He reckoned it was from repeatedly being flexed in one plane.

 

[geoffretired]

Anecdotally, an engineering oriented acquaintance of mine recalled measuring an extremely well shot set of ali shafts and found that they had become oval in cross section over time. He reckoned it was from repeatedly being flexed in one plane.

So the trick is to allow them to age harden at the rate that matches the flattening which will weaken them.
There must be a formula for that; I shall put on my inventing formula hat.