Testing the String-bed stiffness of badminton racquets.

Discussion in 'Badminton Stringing Techniques & Tools' started by stringtechno, Nov 4, 2013.

  1. yan.v

    yan.v Regular Member

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    I'm my stringer :p

    I usually leave prestretch on for every string, but set it higher for BG65 and VS850. Even BG80 loses tension so by leaving prestretch on (with only 10% prestretch, it doesn't lose all of it's elasticity), it helps minimizing the tension loss while retaining playability.
     
  2. stringtechno

    stringtechno Regular Member

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    Hi guys,

    We would appreciate to get some more info from you about this:

    - Do you think that it makes sense to check the string bed of badminton racquets, or is this less important than in tennis?

    - At what loss of tension does a badminton player want a restring?
    Tennis players 20 % loss of tension does not feel good anymore for most players.

    - Is there any other testing method that is used except listing to the sound of the string bed after hitting it?

    Thanks for supporting our “project”.
     
  3. visor

    visor Regular Member

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  4. heroclass

    heroclass Regular Member

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    I used to leave the string pulling on my drop weight until I finish weaving the next hole(around 10-15 secs or maybe even 20 depending on shared holes), now ive been just pulling and grabbing my clamp i would clamp the string right away(1-3 secs of pulling). I found that my old method made the string bed TOO stiff as when i play i dont "feel" the bird anymore. its just too stiff. The new method i believe is better because I "feel" the bird once again and the playability is much more satisfying. I pull 30/32 lbs. we dont want the strings to lose its elasticity.
     
  5. visor

    visor Regular Member

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    [MENTION=40185]heroclass[/MENTION]
    Just out curiosity, at that tension you're playing plastic or feather?
     
  6. heroclass

    heroclass Regular Member

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    feather shuttles
     
  7. visor

    visor Regular Member

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    ^ I have a feeling that your first method is giving you a more accurate and more stable tension. In other words, with your second method, there's more significant tension loss after stringing thru remaining elongation and you're actually playing with perhaps 28/30 lbs. :)
     
  8. heroclass

    heroclass Regular Member

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    That's what I thought too however I had two arcsaber 10 and each strung differently with same strings with my old method as well as new method. Both resulted in Same tension after playing
     
  9. visor

    visor Regular Member

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    ^ How'd you know same tension? Same stringbed frequency?
     
  10. heroclass

    heroclass Regular Member

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    Yes. I hear the frequency with my ear. Of course that is not the most accurate way in measuring, however the differences is so minimum that not even the human ear cant pick up.
     
  11. visor

    visor Regular Member

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    So probably then your method 1 has over pulled the string beyond its elastic limit. Is the tension retention better on method 1 since there's not much elongation remaining?
     
  12. mater

    mater Regular Member

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    Did he mention if he also pre-stretched before hand?
     
  13. stringtechno

    stringtechno Regular Member

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    Our system measures deflects the stringbed (or racquet with the stiffness test) over a fixed distance and measures the force that is needed for this deflection.


    IMO this is a very good and accurate way of stringing. I think that it is better to lower the tension than switching to method 2.


    If you hit the total elongation occurs in the string, so remaining + elastic. The elastic elongation recovers, part of the remaining does not recover ((depending on the time) so the tension in the string goes down.

    So you never lose you the actual elasticity.


    I certainly agree on that.
     
  14. jerby

    jerby Regular Member

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    I think this is quite an interesting way to look at it. To my knowledge there're several factors that influence the 'feel' of your stringjob:
    1) the racket it is strung in, stiffness of the frame and stringing pattern
    2) stringtension
    3) stringingpattern and stringing practise (type of machine, way it is strung)
    4) type of string (stretchy or stiff, thick of thin)

    Now, for a lot of people it's not practical to go over all these variables to get a racket strung well. So in this sense, introducing a new variable "SBS" that combines all these factors int one simple and understandable number would be quite a good idea. (Much like a Von Mises yield criterion in engineering).
    However, the question to be asked is then: does an indention-test cover all these different factors?

    I usually play with bg80 (0.68mm) or an apacs string of 0.67mm at 31lbs. Now theoretically I could string bg65 or 65titanium (0.70mm) at at tension higher than 31lbs to get the same "SBS". These thicker stretchier string would be just as stiff.
    However, no matter how high I string 65 or 65ti, they still feel different, even if the SBS would be the same (I tried 31-34lbs).
    So how can SBS be used to solve this problem?
     
  15. stringtechno

    stringtechno Regular Member

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    Sense of the project / cooperation

    [TABLE]
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    [TD="colspan: 2"]I would like to divide the answer to your post in 2 parts:

    The use of the SBS test In general:

    For this reason the SBS is widely used in tennis, it makes it easy for players and stringers. The players just ask for a certain sbs and they can check the playability of the stringbed by measuring the sbs test after playing with the string bed.

    The SBS test can offer the following information:
    - A stringer can check the “accuracy” of himself and his machine.
    - To measure the loss of tension after stringing and after playing with different strings.
    - To test the “sweetspot” size of stringjob.
    ( A stringbed is always stiffer at the side were the stringer started with the cross strings)
    - The relation between certain strings and the best stringing tensions. In our tennis-system we never combine stretchy strings with high SBS.
    It is much better to string a stiffer string at lower tension than a stretchy string at high tension.
    The stretchy string will lose a lot of tension during stringing already.

    The sense of measuring stiffness of the shaft and of the stringbed in our badminton project:

    We started our badminton project because some “innovative” badminton stringers in the Netherlands want to understand more about the playability of a badminton racquet.
    The combination of the low stiffness shaft with the sbs that goes up more and more is very interesting to analyse.

    Things that we want to find out are:

    - The relation between playability and sbs.
    - The relation between stringing tension and SBS, so that we can make a Tension Advisor for badminton.
    - The influence on the playability of different combinations of shaft-stiffness and sbs.
    - The sense of these high tensions?
    - A classification of badminton strings.

    It would be our ideal when we can cooperate on these items with some very dedicated stringers / players on this forum.
    [/TD]
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    [TD][/TD]
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  16. stringtechno

    stringtechno Regular Member

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    Hereby a little more information about the cooperation that we seek and the offer that we make.

    There are 3 main objectives in the project:

    1. To create a Tension Advisor for badminton, which translates the stringing stiffness into Stringing result (stringbed stiffness), for different head-sizes, number of strings and types of strings.

    2. To classify badminton strings like we do for tennis, and couple the Tension Advisor to the different classes of strings.

    3. To find the influence of stringed stiffness and stiffness of the shaft on the playability of the racquet. Finding best combinations of shaft stiffness + sbs seems important also.

    If we want to create a good basis for this we need feed back from a number of stringers / players so that we can enter the data that they supply into a data bank.

    We offer the Stringlab 2 test system for a very special price to those who want to participate.

    We already have some known badminton stringers on our list who will be contacted soon.

    Please let me know if you are interested.
     
  17. yan.v

    yan.v Regular Member

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    I think this is an interesting project, so this is definitely something I'm interested in. I was planning to create my own tools to measure things such as tension/stiffness, flexibility, balance point, swing weight, etc. but I'd much rather participate in an existing project than start my own as I'm being flooded with rackets to string at the store..
     
  18. stringtechno

    stringtechno Regular Member

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    If those who are interested in participating can send an email to stringway.fred@gmail.com we will contact them directly about a proposal for the participation.

    Thanks
     
  19. stringtechno

    stringtechno Regular Member

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    For those who are interested to participate in the project.
    The picture shows the test unit for badminton, to measure SBS and shaft stiffness.
    The transparent disc takes care that only the string bed deflects.

    The price for the unit will be lower than the introduction offer on our site. The quantity for those who want to cooperate in the project is limited.

    [​IMG]
     
    #39 stringtechno, Nov 11, 2013
    Last edited: Nov 11, 2013
  20. kakinami

    kakinami Regular Member

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    I never use it unless requested. ES5 Pro Machine
     

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