# Recurve Button spring size/pressure



## GoldArcher403 (Jun 25, 2014)

I use medium. IMO, getting a good tune right in the middle of the range gives you equal slack in both directions should you need to change.


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## chrstphr (Nov 23, 2005)

for the most part, i have found that

small diameter arrows

for 10-25lbs use softest spring
26-42lbs use medium spring
42-54 lbs use hard spring 

larger diameter arrows

10-20lbs use soft spring
21-35lbs use medium spring
36-50+ lbs use hard spring

of course this is not a hard line. many may get a great tune using medium spring for everything, or hard spring for everything. 

Chris


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## erose (Aug 12, 2014)

Yeah I discovered the same thing. It seems that higher the draw weight the stiffer the tension needs to be.


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## zal (May 1, 2007)

12 x weight of bow in grams, so 40# = 480g. Spring that sits in the middle of the adjustment range at that point. Measured against scale, from the point when the tip starts moving.

I measure my own bows slightly differently, but that is a good rule of thumb, which has been used by some very experienced coaches and Olympic level competitors for years. Works best with stiff plunger tune (I prefer Park's test).


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## iArch (Apr 17, 2015)

I use a medium spring most of the time.


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## arrowchucker222 (Jun 17, 2013)

Soft most of the time, I'm shooting 35-49# most of time


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## j.conner (Nov 12, 2009)

Medium spring for me (Beiter plunger) although I have noted a preference for soft springs on the AAE plungers. I shoot 40#-45#.


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## JustSomeDude (Jan 27, 2013)

What plunger? Or is that what you see in general? I am a 'stickbow' shooter and JUST got my first target setup for Barebow. It came with an AEE Lok plunger but I couldn't get it to tune 38#-44#. The spring was very light but I had nothing to compare to. I ordered a couple of heavy and extra heavy tapered and all is well now. Though I am running it cranked out pretty far.



chrstphr said:


> for the most part, i have found that
> 
> small diameter arrows
> 
> ...


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## chrstphr (Nov 23, 2005)

JustSomeDude said:


> What plunger? Or is that what you see in general? I am a 'stickbow' shooter and JUST got my first target setup for Barebow. It came with an AEE Lok plunger but I couldn't get it to tune 38#-44#. The spring was very light but I had nothing to compare to. I ordered a couple of heavy and extra heavy tapered and all is well now. Though I am running it cranked out pretty far.


Beiter, AAE etc. 

any plunger that comes with different strength springs.

Chris


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## JustSomeDude (Jan 27, 2013)

Thanks. I'm getting a new Master Lok today so I'll have something else to compare to.


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## Neo888 (Feb 4, 2009)

What advantage could it mean with 24# otf to use the lightest spring in a Beiter plunger instead medium one, assuming strength adjusted the same, approx 300 gram? With the medium spring it is pretty much turned out position, well out of medium setting.



chrstphr said:


> for the most part, i have found that
> 
> small diameter arrows
> 
> ...


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## rat4go (Apr 14, 2011)

Interesting to follow this as its been something I've wondered more out of curiosity than anything as its probably the only area I have managed to subdue the engineer in me and just find/ shoot what seems to work.

Keep in mind that the force that it takes to start to move the plunger can probably be achieved with any of the springs, albeit with different preload. Assuming a soft spring with much preload can match a stiff spring with minimal preload, the area where the spring matters is AFTER the plunger starts to move. Preload for our plungers is effectively the number of turns on the plunger after the tip has enough spring force on it to seat it without rattling. Ignoring centershot, adjusting your plunger only adjusts preload.

The physics.....

In general terms, spring stiffness is expressed in force per distance compressed. Newton/mm or similar. 

Example with made up numbers.. If you preload a 10 newton/mm (soft) spring by 3mm (say 3 turns past seated) , it takes 30n to get it to move. A 15 newton/mm (medium) spring preloaded to 2mm (2 turns) takes the same 30 N to compress it more and a 20 Newton/mm (stiff) spring preloaded 1.5mm (1.5 turns) takes the same 30N to get it to move. 

Technically, assuming the same "force for initial movement" setting, the spring stiffness really impacts how much distance the plunger compresses after it starts to move for a specific bow/arrow/set up.

The suggestions for using draw weight to do initial spring selection sorta makes sense to me as higher # probably creates increased force on the plunger and a stiffer spring won't let the plunger compress as much as a soft one and I think we want the plunger to compress some, but too much is bad.

Much theory....I only wish I knee how to apply the above physics to get more arrows in the gold.


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## chrstphr (Nov 23, 2005)

Neo888 said:


> What advantage could it mean with 24# otf to use the lightest spring in a Beiter plunger instead medium one, assuming strength adjusted the same, approx 300 gram? With the medium spring it is pretty much turned out position, well out of medium setting.



I put it to you this way..

Why have different springs at all? Why doesnt Beiter just give a medium spring and be done with it. Surely you can use the medium spring let out to achieve 300 grams. Surely you can turn it all the way up for a very stiiff plunger.


The answer is better adjustability and reaction for the force put into the plunger. I prefer a plunger spring compression that is in the middle of the range than at its extremes. The spring will react better and more consistent with the force applied to it.
YMMV.


Chris


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## Neo888 (Feb 4, 2009)

It sounds logical about more consistency at middle setting, never thought about it until now. Definitely I will give a try, even if I will never realize the benefit at my level of shooting, at the end if I believe it helps, it will


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## zal (May 1, 2007)

When I've tried internationally competitive archers' plungers, they have varied from rock hard to completely, utterly unmovable ones. When I've tried beginners, intermediates and hobbyists plungers, they have been from very weak to somewhere where I would start at. Poundage is a variable, but it doesn't explain all of it.

You don't "need" the plunger to get a good tune, it is just a tool which allows bad shots to be not quite so bad. If you shoot plenty of bad shots, you might have some use for it, if you don't, those archers tend to remove all variables that can go wrong in a competition.

Also, you need to know how to tune the bow properly. Plunger tuning only comes after you can get a good bareshaft tune up to 70m and you are ready to start microtuning.


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## Cephas (Sep 7, 2010)

It may be helpful to have a look at this resource from Beiter. It shows the range in Newtons of pressure in relation to the preset tension for the three springs available with its plunger. The graphic is at the bottom of the document.

http://www.wernerbeiter.com/en/information-downloads/datasheets/Plunger_GB.pdf


Soft spring takes you from about 1N to 6N
Medium spring from 3N to 9N
And Hard from 5.5ish N to about 14ish N


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## Cephas (Sep 7, 2010)

There is overlap in the Beiter. We've always found an acceptable setting then chosen the spring that can get us that setting with the greatest range to fine tune.


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## chrstphr (Nov 23, 2005)

zal said:


> When I've tried internationally competitive archers' plungers, they have varied from rock hard to completely, utterly unmovable ones. When I've tried beginners, intermediates and hobbyists plungers, they have been from very weak to somewhere where I would start at. Poundage is a variable, but it doesn't explain all of it.


I have also found this to be true. I think the better you get at your release, the stiffer you can have the plunger and get a better tune. 




Cephas said:


> There is overlap in the Beiter. We've always found an acceptable setting then chosen the spring that can get us that setting with the greatest range to fine tune.


agree...

Chris


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