Pressure buttons - how do they really work?

4d4m

Member
Just musing on the above. I'm struggling to understand why a spring loaded plunger helps. I can definitely see the value of being able to finely adjust the centre shot for different spines and diameters of shaft, so the arrow comes out of the bow in as near a straight alignment with the string and riser as possible. BUT, why have a sprung plunger, why not a solid button? What is the purpose of allowing the arrow to press the button in during the power stroke?

It would seem to me to facilitate more variation not less. If it is intended to "soak up" some of the variation of the archer's release, like a car suspension, why is it not damped? The arrow will push in the plunger and then the plunger will spring back, pushing the arrow out. Won't the "bounce" make the arrow move out more than it would against a solid rest or button?

Post is motivated out of curiosity, nothing more. I was "that kid" who always wanted to know why and how things actually worked. :)
 


LionOfNarnia

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LUV a good technical discussion, me ;)

Is it even safe to start from the assumption that buttons give better scores?

I'm still trying to get my head around why some pay 70 quid for a spring in a tube. Hope this thread really lights up!
 


4d4m

Member
Is it even safe to start from the assumption that buttons give better scores?

I'm still trying to get my head around why some pay 70 quid for a spring in a tube. Hope this thread really lights up!
I think that's a reasonably safe assumption, given they're so ubiquitous. I've never seen anybody in target shooting a full recurve off a bare shelf, but I've not done many tournaments. I guess there may be one or two but a tiny minority. So they must work. I want to know why.

I can understand the quality angle. Just pushing in the plunger with my thumb on the basic Cartel of SF (can't remember which) supplied with my beginner kit, then doing the same with Shibuya ones, you can feel the latter are so much smoother. That has got to make a (slight) difference in consistency, but the question here is do they need to push in.
 


geoffretired

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I remember James Park's set up process from some years ago used to start with a solid button( replace spring with matchstick).
Then he changes his procedure and started it with a very stiff spring. I think his reasons were that the shaft was less likely to kick away from the button( or bounce off it). The shaft will stay in contact with the sprung button over a longer travel, I suspect, perhaps that's a good think while the shaft is getting such a hard shock at start up.
Compounds use sprung blades; perhaps for similar reasons.
 


malbro

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I'm still trying to get my head around why some pay 70 quid for a spring in a tube. Hope this thread really lights up!
They are probably the same people who would pay over a £1000 for two pieces of bent wood attached by bolts to a third piece of wood with a piece of string attached to them.:D
 


Del the Cat

Well-known member
LUV a good technical discussion, me ;)

Is it even safe to start from the assumption that buttons give better scores?

I'm still trying to get my head around why some pay 70 quid for a spring in a tube. Hope this thread really lights up!
Actually it's not a safe assumption...
A pressure button is just a quick convenient and probably more reproducible way of making the adjustments without resorting to experimentation with layers of leather. That doesn't mean that the leather wouldn't give as good a result.
Del
 


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geoffretired

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Supporter
A pressure button is just a quick convenient and probably more reproducible way of making the adjustments without resorting to experimentation with layers of leather.
Yes, it is a simple way of allowing some adjustment. It can be adjusted back to where it was, too; which is another benefit. The spring loading is easily adjusted, possibly easier than the leather?
 


KidCurry

Active member
... I'm still trying to get my head around why some pay 70 quid for a spring in a tube. Hope this thread really lights up!
For recurve I think you probably can't improve on the Shibuya DX. However, I shoot barebow, I string walk and use a DX. String walking changes the amount the arrow is drawn and effectively the dynamic stiffness of the arrow. The more you string walk the stiffer the arrow and, to keep the same point on gold, you need a slightly softer button. You can relax the spring on a DX, fiddly, but with a Beiter click stop it is easy and precise. I may think about one after Christmas. Besides, shooting barebow, what else is there to spend money on :)
 


Whitehart

Well-known member
IMO The Beiter button is worth every penny, quality of all the materials and a polished plunger tube.
Archery is all about consistency and this is what the Beiter button has in spades - the springs do not change over time and the plunger tips do not wear after a few 1000 arrows. I am a fan of the DX great value, very well made and the lack of easy adjustments that stops archers fiddling when they shoot be working on form. When I switched to the Beiter button arrow flight was like chalk and cheese. Spring tension and centreshot were set the same (some fine adjustment needed for better arrow flight) but clearly the springs and movement are much more consistent from shot to shot as seen on my scoresheet. Been using the Beiter for the last 2 years with the odd bareshaft check here and there I have not had to make any adjustments - with all the other buttons overtime checking arrow flight, retuning and making adjustments has been a must throughout the season as the materials change their properties.
 


Kerf

Supporter
Supporter
Excellent video. Looking at it closely I wonder if the button only starts to move outward again with the flex of the arrow, i.e. the arrow allows the button to move, or whether the button actually exerts a little outward pressure on the arrow thus helping the flex? Either way, it’s a fascinating vid. Thanks for posting.
 


geoffretired

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Yes, great video.
I watched it in small bits and it seems that the bend in the arrow pushes the button inwards. I assume the arrow has enough momentum(?) to overcome the spring's resistance. In the next stage, the arrow is flexing the other way so the shaft is travelling forwards and away from the button, allowing it to spring back out. Would the button put a bit more bend in the shaft? Or would the contact point of the shaft be pushed further left. moving much of the shaft with it?
I guess there will be a little of both.
 


LionOfNarnia

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I've honestly lost track of how many times I've watched that!

First observation is that whatever is happening, it's happening very quickly!

- Many questions, few definitive answers, but a good & encouraging start!

2nd Observation - life would have been made much easier if the 'dials' on the video were a lot clearer!

This vid, by the same dude(s), offers similar hints as to 'what's going on, and when'....


I'll try & put some 'guesstimate' numbers together before Sunday, unless someone else beats me to it ;)
 


LionOfNarnia

Supporter
Supporter
Haha! First numbers are in (Hey there's no sportsball tonight)!

From when the tip of the arrow starts moving to when the plunger starts moving = ~1.47mS

From then until the plunger is fully depressed = ~0.58mS

From then until the plunger is fully extended again = ~0.58 mS

From then until the arrow fully clears the bow = ~ 2.35mS

Total time - roughly 5mS
 


Senlac

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Supporter
”....BUT, why have a sprung plunger, why not a solid button? What is the purpose of allowing the arrow to press the button in during the power stroke?”
The vids show that the button is a shock absorber. I.e. when you release, the string moves laterally off your fingers (inevitably), and at the same time a sudden shove is given to the back end of the arrow. For a millisecond, the front end of the arrow, where 30% of the weight is, doesn’t realise the back end has started moving and then it takes a little time to get moving (it has inertia). So the arrow bends laterally, and So the front kicks inwards towards the riser. The purpose of the button is to manage this shock inward kick optimally and consistently. That means plungers that are low-friction, and springs that are consistent and close to linear in resistance-compression. The Beiter ones come with graphs shoing spring resistance vs. compression, i.e. they’re calibrated springs. So not cheap.
 


chuffalump

Member
For a start, the spring plunger gives less disturbance to the arrow. Like Del's leather. The plunger takes some of the bend out of the arrow that would have happened against a rigid surface. So, the arrow doesnt bend as much, doesn't rebound as much. Smoother acceleration, less wiggle in flight.

Secondly, by moving out of the way for part of the power stroke whilst also allowing the tip to move round to centre.... I wonder if you can shoot stiffer arrows than would be required with an equivalent trad bow. Out of my experience zone there.
 


KidCurry

Active member
I shot my Bodnik Slick Stick for a couple of years, just for fun. It was critical on arrow spine for really consistent results. I now shoot recurve barebow and with the button I can use arrows from .610 up to .500 no problem, they all tune well.
 


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