Tension loss experiments / 1-piece vs. 2-piece and others

Discussion in 'Badminton Stringing Techniques & Tools' started by s_mair, Jul 12, 2021.

  1. Mark A

    Mark A Regular Member

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    Oh, aye - a very "busy" turntable.

    Kicking myself that I never tried it, to be honest - would have been worth it just for the memes.
     
  2. s_mair

    s_mair Regular Member

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    Part III: Fixed Clamps vs. Flying Clamps

    ....you know the drill by now.

    Experiment setup
    Rackets: 2 x Victor Super Waves 36
    String: Gosen G-Tone 5 (0.65 mm), yellow
    Stringer: myself
    Machine: StringMaster Deluxe with WISE tension head
    Pattern and process details were identical best possible (Haribito 1-Piece, no added tension before tie-off knots, no double pulls).

    Setting
    Both rackets: 12 x 12 kg (26.4 x 26.4 lbs.), no pre-stretch
    Racket #1: Fixed clamps
    Racket #2: Flying clamps (one Yonex, one Hi-Qua clamp)

    Results
    Data for racket +#1 are a carry over from Part II, so it was not a perfectly simultaneous setup this time. So temperatures and humidity levels were different. I have decided to shorten the experiment duration to 2 weeks, since previous results have shown that there are no significant effects to be expected after that. Racket #2 was not played during these 2 weeks.

    Let's look at the graph:
    upload_2021-8-31_10-45-50.png
    Raw data: https://www.dropbox.com/s/z0kfv722n2iowhl/Tension Loss Flying Clamps.xlsx?dl=0

    Main focus immediately jumps on the significantly different starting value.

    The flying clamp job came off the machine ~65 Hz lower than the fixed clamp one which translates to around 2-3 lbs.

    And frankly, this is more than I would have expected before.

    It has to be said that this was my first job using flying clamps only but I am confident not to have messed it up completely.
    To validate the suprisingly huge difference there, @speCulatius (thanks a lot! :)) offered to repeat the same experiment with two of his Adidas P8 and the numbers also showed a difference at around 60 Hz in the starting value.
    With more routine and some process optimisations, I can imagine to improve the starting ping slightly (maybe <10 Hz?), but imo it's impossible to just remotely compensate those ~60 Hz without turning up the set tension.

    Bottom line
    The working principle of flying clamps is causing a clearly measurable tension loss during the string job. I cannot really point my finger on the why and how, but the numbers are very clear on this.

    If your machine has fixed clamps, then use them!
     
    #62 s_mair, Aug 31, 2021
    Last edited: Aug 31, 2021
  3. speCulatius

    speCulatius Regular Member

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    Maybe I should add the details if anybody is interested (you could have done that, Simon):

    Rackets: 2 x Adidas Wucht P8 3U
    String: Gosen G-Tone 5 (0.65 mm), yellow
    Stringer: myself, not Simon
    Machine: SuperStringer T20 Dropweight machine w/ Chudeks aka Simon's old machine
    Even up to the level that I cheated with a fixed clamp when switching to the crosses to avoid a double pull (almost in the center of the head with this pattern) and ensure that the lower tension was directly coming from the flying clamps.

    Tension: 13kp squared

    It should be said that I had issues measuring the ping myself. I tried several apps, but couldn't get any usable reading whatsoever. Recording the pings and having Simon measure them worked just fine though. Thinking about it, that also gives it to the same human factor to make the reading "errors", so that might have been a good idea anyway. I used my regular rackets, so I cannot ensure that they're played evenly, but it was more about the ping right off the machine.

    Flying: 1408 Hz
    Fixed: 1468 Hz

    Difference: 60 Hz

    I did string with flying clamps for the first two years of my stringing "career" and I was still awfully familiar to it. It did feel wrong, though.
     
  4. s_mair

    s_mair Regular Member

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    ...sorry... :(

    Funny enough, it was a lot easier to get usable readings by measuring the recorded pings coming out of the laptop speakers than measuring the actual racket live. Surprises after surprises.
     
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  5. kwun

    kwun Administrator

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    I am not too surprised by 2-3lbs. As mentioned before, each time flying clamp engages, there are 2x string pulling on a single string. there will be massive tension loss there which from previous grommet friction experiment shows it cannot be recovered with the next pull.

    it'd be more interesting to have pre-stretch turned on since that'd in theory recover a little bit of tension. however, it will also help the control racket so the benefit might end up marginal.

    excellent experiment yet again. thanks very much for the effort!!
     
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  6. flyingcords

    flyingcords Regular Member

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    It could be interesting to have your feeling about the two rackets you used for this experiment in play, during a game session. (the hidden question could be : "does a racket stringed with flying clamps feel the same as a racket stringed with fixed clamps at 2 or 3 Lbs less tension ?")
     
    #66 flyingcords, Aug 31, 2021
    Last edited: Aug 31, 2021
  7. speCulatius

    speCulatius Regular Member

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    I played both rackets yesterday and I cannot complain about either one. I cannot really say more, because I recently moved to a very different climate than I'm used to and the hall needs some time to adapt as well (the lighting is terrible) and it was my first time playing here.

    If you're still interested in more details, I'll give my best, but take it with more than just a pinch of salt.
    I started to play with the flying clamp racket and it felt great. Even if it turned out as 12 kp in the end, a freshly strung GT5 at that tension is well in my comfort zone. The reason why I went higher is, that I know that I'm comfortable with GT5 at higher tensions and it lasts quite long while slowly losing tension. Similar to BG80P, in my opinion, just that I like GT5 a lot better. Also, I felt that moving away from the country of too slow shuttles and into warmer climate might ask for it.
    Switching to the fixed clamp racket, it felt just as great, but a bit more punishing on off center hits. The sweet spot was just a bit smaller. Today, I only played with rackets strung with fixed clamps at 13 kp and I really like it. The repulsion is awesome. It's just not for you if you like a "shuttle holding feel", but then the P8 is the wrong racket anyway.
    However, there was nothing I could complain about for the flying clamps job. I was not focusing on reviewing the stringjob, though. Unfortunately, it'll be almost two weeks before I'll get on court again.
     
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  8. s_mair

    s_mair Regular Member

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    I've decided that there will be one last experiment before this thread will be concluded: Constant pull vs. lockout.

    Done with a WISE of course, but should be okay to get a feel for how much a (well calibrated) lockout tensioner (aka crank) is losing compared to a constant pull machine. I will reduce the experiment to 1 week since the previous data has shown that the most movement is happening within the first 5 days after the string job.

    Here's how the reading looks like with the constant pull feature disabled:


    Anyone wants to take a guess regarding the starting value of the lockout job compared to the constant pull one?
     
    #68 s_mair, Sep 10, 2021
    Last edited: Sep 10, 2021
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  9. Antxn

    Antxn Regular Member

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    This will be very interesting and is something i'm looking forward to!

    Sent from my SM-G975F using Tapatalk
     
  10. flyingcords

    flyingcords Regular Member

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    There is still hope that there will be other ones, now that you have initiated this thread (you or someone else could for example add this one : Dropweight VS Wise) ;)
     
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  11. speCulatius

    speCulatius Regular Member

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    Working with a dropweight, I don't think there's a ton of value in that. I know that my dropweight pulls slightly higher than the scale says (almost exactly the correct value when the gripper is horizontal on the racket side, iirc, the further it comes to the dropweight side, the more it gets), but not enough for me to want to change anything. So I can "change" the tension by roughly 1 lbs pulled, depending on where the gripper is... with the position of the sticker varying even slightly between machines, different grippers, different people operating the machines, I think there is too much variation even when fixing some of the variables.
    Where would you expect a difference is coming from, assuming that both machines are calibrated exactly the same?

    However, some tennis stringers did exactly that experiment and there was a YouTube video on it (in German). I don't find it anymore, but the result was a big difference on the first try, the electronic tensioning being lower, probably because the guy talked too much, but then the rackets all came out about the same. It was two different stringers, each on one machine, but they did switch machines to rule out the human variable.
     
  12. flyingcords

    flyingcords Regular Member

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    I completely agree with you. There is probably no interest in this experiment (dropweight VS Wise), the human factor is too important, when using the dropweight. Perhaps the little difference would be the constant pulling of the Wise, probably more efficient than the dropweight.
     
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  13. SnowWhite

    SnowWhite Regular Member

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    That's the advantage of an electronic machine; consistency. No matter how precise a human can work with the dropweight, it will never be as precise as the Wise. Every single string will be perfect. Of course a good stringer will get close enough to perfect on a dropweight.

    But I don't think the constant pull of the Wise will make any difference. By its design, a dropweight machine is a constant pull machine that should pull the exact right tension when horizontal.

    The main advantage of electronical machines is speed.
    The main advantage of dropweight machines is that when the zombie apocalypse comes and you don't have a battery or generator, at least you can still string your racket in time for clubnight.
     
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  14. s_mair

    s_mair Regular Member

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    Part IV: Constant Pull vs. Lockout (aka crank)

    ....this concludes my series of experiments in this the thread for now. :)

    Experiment setup
    Rackets: 2 x Victor Super Waves 36
    String: Gosen G-Tone 5 (0.65 mm), yellow
    Stringer: myself
    Machine: StringMaster Deluxe with WISE tension head
    Pattern and process details were identical best possible (Haribito 1-Piece, no added tension before tie-off knots, no double pulls).

    Setting
    Both rackets: 12 x 12 kg (26.4 x 26.4 lbs.), no pre-stretch
    Racket #1: Constant pull
    Racket #2: Lockout (constant pull function on the WISE was disabled)

    Results
    Racket 1 is the same data which was used in part II and III. Temperature and humidity were pretty stable over the past weeks, so there should be very little effect coming from the storage conditions. Duration was again reduced to 7 days since all previous measurements have shown that the most significant drop happens within the first 5 days after the string job.

    And here's the graph:
    upload_2021-9-16_19-25-50.png
    Raw data: https://www.dropbox.com/s/4bz1evm30k9x9d1/Tension Loss Lockout.xlsx?dl=0

    And again, the only real difference is in the starting value, which is about 25 Hz or ~1 lb. lower on the lockout job.

    If you look at the video above and the tension loss curve, the reason is simple to explain. During the time that is needed to clamp the string, it has lost some of its inital tension due to its elasticity. And since the timing there is crucial for the end result, I also focussed on being as quick as possible with the clamping. So the slower you are at clamping, the lower the effective tension in the end result will turn out.

    Bottom line
    As expected, even with a well calibrated lockout tensioning mechanism (aka crank), there will be some tension loss during the string job compared to a constant pull mechanism like a drop weight or an electronic tensioner. Going by gut feeling and hearsay only, I would have assumed the difference to be bigger to be honest. The effect is smaller than what is lost with using flying clamps, as seen in part III and can easily be compensated if you want to. The loss most likely will even be less if the string is tensioned two or even three times on every pull.

    So imo this is really good news for all the crank machine users out there. Just make sure to have it calibrated properly and be quick with the (fixed!) clamps, and there is very little to be worried about. In an extreme (but not so rare) combination of crank machine plus flying clamps, the result is likely to end up a whooping 3-4 lbs. lower than a constant pull machine with fixed clamps.
     
    #74 s_mair, Sep 16, 2021
    Last edited: Nov 10, 2021
  15. Mark A

    Mark A Regular Member

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    Another suggestion for Simon: hand-prestretch vs no prestretch, constant pull.

    I spent my entire career doing hand prestretch, and I would love to know how much time I pissed away ;)
     
    #75 Mark A, Sep 25, 2021
    Last edited: Sep 30, 2021
  16. s_mair

    s_mair Regular Member

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