How far can you push an arrow?

Senlac

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This is about recurves with ACEs.
And it is a result of a chance remark from Timid Toad a few months ago along the lines of.... "I can get any of five spines to tune well with my recurve".
So this post is about... what range of recurve poundage (OTF) can you tune to shoot well with the same ACE?
It started with me finding that 29" ACE 670s with 100grn points tuned well with my 36# OTF recurve (WW InnoMax). Then, as I increased poundage, I found that the same arrows could be made to tune well all the way to 43#. All I had to do was increase button pressure - from mid-way on the weakest spring (Better) to way up on the hardest spring.
Any similar experiences?
 

Rik

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hmmm. Not exactly the same... I kind of tested the other way, as I had shafts knocking around from 750 up to 620 spine.
I found I can set them all up to fly right. But the 620s produced noticeably worse groups (twice as large as the 670s).
According to the normal advice (based on Easton charts, with modifiers from Border), 650/670 should be "right" for my setup, but I may go a size down on my next set of shafts.

If I were taking it seriously, I'd work my up and down the spines and find on each end where the groups open up, then pick the size that falls midway between...
 

Timid Toad

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Yes, pretty much my experience. I can get a range of spines to shoot right, but I'm looking for the tightest groups at 70m with as much forgiveness of my sloppy loose as I can get. Of course, I'll choose and shoot only one of those spines for the season, and probably start again next season.
 

dvd8n

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Yes, pretty much my experience. I can get a range of spines to shoot right, but I'm looking for the tightest groups at 70m with as much forgiveness of my sloppy loose as I can get. Of course, I'll choose and shoot only one of those spines for the season, and probably start again next season.
Why do you start again next season? Are you assuming that something has changed every year?
 

Timid Toad

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Yes. Arrows wear fractionally, I change form, I change kit. In practice I always shoot a bare shaft every end so I can see if something is coming loose, changing, whatever, anyway. But moving outdoors again, for example, a thorough tune and once through all my equipment is a good idea. If I end up using a different spine next season, it'll be because something has changed, and if it hasn't, I'll be on the same spine. Whatever the result, checking is important both from a physical and psychological perspective.

Sid describes this thing with the many spines tuning as the bell curve. While any arrow under the bell curve could be described as tuning, ones at either extreme may be very twitchy or group poorly. The challenge is finding the sweetspot.
 

mbaker74

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When you say tune do you mean bare shaft tune? so your getting bare shafts in the group with fletched at 30m with changing button pressure only?
 

Senlac

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mbaker74: yes, I mean bare shaft tune at 25-30m. At these distances an acceptable tune is fletched and unfletched within 4? or so.
 

mbaker74

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Ah ok

I have always approached bareshaft tuning following the method Simon Needham gives In his book, which is

1. Check limb alignment etc
2. Set centre shot to point just to the left of the string ( right handed archer)
3. Set sight pin directly above arrow centre
4. Adjust button pressure so fletched arrows hit in a vertical line with the gold then don't touch sight or button
5. Shoot fletched and unfletched and set nocking point to get correct vertical grouping of unfletched with fletched
6.Adjust horizontal grouping of unfletched by adjusting limb weight primarily, then fine tune with bracing height string strands, arrow point weights etc.

I can see the sense in this method as you are making changes to the amount of power going into the arrow and the factors which effect the arrow bending, so your fine tuning how the arrow flys.
I cant quite get my head round how adjusting the button pressure is doing anything except pushing the unfletched arrows either left or right until you have pushed it far enough to line up with the adjusted flight of the fletched arrows.
It may well work well, I dont know having never tried it, just to my mind the Simon Needham method seems to make more sense. Also, this method will definitely not allow you to tune 5 or 6 different spines, which to me makes it more indicative of the correct spine for my shooting style and kit?
 

Timid Toad

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Shooting super recurves, I don't get more than 1lb of weight change from fully wound in to fully wound out. None of this 10% laugh. Messing with poundage is ok if you have a conventional ILF recurve and might be a long way out with spine. As it is, I don't need to. A button absorbs the flex of the arrow. A weak spine pushes harder towards the riser, so needs to be resisted with a still button. The other way round for a stiff spine.

I spent a little while looking at how off-the-shelf shooters tune. They don't have the luxury of a button, most can't alter poundage and have to work harder to get a decent result by packing out the window to alter the arrow's centreshot. They look for nock following point in flight.
 

Rik

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Actually, that Needham approach would probably work just fine for a range of spines... You just wouldn't end up doing much at (6)...
 

kauppi

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What is the main purpose of a plunger? Some claim it should correct occasional bad release, some say it helps tuning arrow to the bow.

If one needs to compensate suboptimal spine with very weak or stiff plunger, will it lead to less forgiving setup/tune?
In other words: can plunger help with botj if it has been adjusted to extreme settings?
 

geoffretired

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One good use for a plunger is to allow different width of shaft to be shot from the same bow. The button can be set so any arrow within reason, can be set to face straight ahead; or given a slight offset if that should be required.
A rigid button would do that, but a sprung one seems to give a better launch; perhaps it avoid a bounce effect. According to James Park's studies he found no evidence that a particular setting of the spring can reduce group size.
A very soft spring setting can make things very difficult to control, as a slight variation in the release can compress the spring by significantly different amounts meaning the arrow is launched in a significantly different direction.
If a very soft button is needed to get the arrows to fly in the required direction, then another option to give a similar effect is to set the centre shot further in towards the riser. The soft spring allows the arrow to press the button in far enough to launch from closer in to the riser, but the softness can bring variations as mentioned earlier, so better to position a stiffish button closer in from the start.
If we view matching arrows as getting the alignment of the arrow, just right at the launch, then the adjustment, left to right, will become part of that alignment matching. In cases where draw weight can be adjusted, that can change the alignment at launch as that gives the arrow more time to get to optimal alignment; or less time if that is necessary. Single weight bows don't have that option and the centre shot adjustment can be all it needs.
In a similar way, a change of brace height can allow the arrow more time to align or less depending on what is required. Changing the weight of the string can give the arrow more/less time to align, too.
So in a way, we either give the shaft a better amount of time to align; or we set it's front end launch position so the alignment is good keeping the time as it is. Or a bit of both to keep our settings away from extreme ones that could damage groups.
 

Rik

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What is the main purpose of a plunger? Some claim it should correct occasional bad release, some say it helps tuning arrow to the bow.

If one needs to compensate suboptimal spine with very weak or stiff plunger, will it lead to less forgiving setup/tune?
In other words: can plunger help with botj if it has been adjusted to extreme settings?
Er. You can't compensate for suboptimal spine with the plunger... Suboptimal spine is the definition of an unforgiving setup. If it's not unforgiving then the spine isn't sub-optimal.

There's a lot of mysticism around plungers, but basically they let you determine which direction the shaft is travelling in when it leaves the bow. Yes, you can fiddle a little to try to improve things like clearance, but that's more or less it.
 
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