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Spring-driven constant pull machine

Discussion in 'Badminton Stringing Techniques & Tools' started by stringtechno, Feb 27, 2019.

  1. stringtechno

    stringtechno Regular Member

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    Because the feedback from users has been very positive about our new MS140 and because we can lower the price considerably we decided to make a special MS140 for badminton.

    The MS140 uses the same kind of drive system as our footoperated machine that we make since 1992.

    This video shows how it works and how accurate it is.



    [​IMG]

    [​IMG]
     
  2. kwun

    kwun Administrator

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    how constant is the constant pull?

    @ 4:46 in the video, disenaging the clamps caused a lot of slack in the string, resulting in a lot of travel in the spring. have you tested that it is still maintaining constant tension there?

    your digital scale shows that it engages accurately, that is really nice. however, there is no movement. the key to constant pull is to maintain constant tension even when slack is introduce in the string (due to clamp release or string lengthening.
     
  3. stringtechno

    stringtechno Regular Member

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    The tension over the hole usefull stroke differs from 12.0 to 12,27.

    The overall quality of the Spring machine is that it is reliable, cheap and accurate.

    But as you know the accuracy of stringing does not count in tenth of lbs of the tensioner but in lbs depending on the clamps, the stringer and the type of string.

    I would like to remember you on this test that we once did on our stringing seminar:

    A tournament stringer with a very nice electronic machines strung 5 racquet at the same tensions, This table shows the result in stiffness it varies from 16 to 28 kg/cm (DT value):

    [​IMG]
     
  4. s_mair

    s_mair Regular Member

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    Doesn't really answer kwun's question I'm afraid. And of course you get different resulting stringbed stiffness values if you change the string and the racket (head sizes). If you compare the values with same stringer, same equipment, same racket and string, the values would be very, very consistent - and that's what it's all about. I keep track of all the stringbed ping frequencies and normally, I consistently see a variance of +-5 Hz between several jobs with same racket and strings. If the spring driven tensioning system is able to provide that, it's all good.

    The scene at 4:46 in the video does look a bit strange indeed. The bar drops significantly when the clamp is released and seems to be going "on block" and hence kwun's question regarding the resulting tension after this drop.
     
  5. stringtechno

    stringtechno Regular Member

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    This answer means that the tension in the lower position of the lever is between 12.0 and 12,27.

    As you can see the lever is still far away from the frame and certainly not at the end of its stroke.

    Because the first pull was a double pull there is less tension in the first string towards the throat. The heads drops further to pull it towards the adjusted tension.


    Yes that is very sure but also quite easy.
    The art of stringing is that you can string with different strings in different racquets at the same stiffness .

    The results in the table are created by one stringer with the same machine and the

    His major fault was only that he pulled tension too quickly. Therefore all elongation in the “slow string” was not developed and in the “fast string” it was.

    After he started to pull slower his results were much more consistent.

    The general question is: Do badminton stringers really string "slow strings" slower than "fast" strings?
     
  6. stringtechno

    stringtechno Regular Member

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    Just in case I misunderstood Kwun’s remark hereby some more explanation.

    The major trick in the MS200 (footoperated machine) and the MS140 is that the tension is constant despite the fact that the force of the spring gets lower towards the end of the stroke.

    In words this is easy to explain:

    The torque of the spring on the leverage is constant while the force of the spring varies.

    This is done by tuning the stiffness of the spring and the angle of the leverage.

    To realize this in practice needs quite some testing but once it is ok it is ok “for ever”.
     
  7. Charlie-SWUK

    Charlie-SWUK Regular Member

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    Not to be a nay-sayer, but what's the benefit of this machine against a dropweight? is it at an incredibly competitive price point?
     
  8. s_mair

    s_mair Regular Member

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    Here are the advantages that I've figured out myself:
    It should be a lot lighter due to the missing weight thing. An interesting factor if you go for a portable machine. Also, the position of the lever bar doesn't influence the actual tension that is pulled (same as in other Stringway machines btw).

    But I'm wondering why those points haven't been promoted really yet instead of throwing smoke bombs like "slow" and "fast" strings. Which is nothing that this machine does any better or worse than others.
     
  9. stringtechno

    stringtechno Regular Member

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    We think that this machine has a number of advantages:
    * The price is nice, it is our cheapest machine cheaper than our cheapest drop weight.

    * The weight is 6,5 kg compared to 16 kg for our lightest drop weight which makes it very easy to transport and to store.

    * It is more high tech:

    - It has the build in drive system that we already offer in the MS200 since 1992.

    - The turntable is very stiff, very accurate to adjust with the spindle and despite that much lighter.

    * It has more features than the drop weight like the knot function.

    * The fact that it is lighter does not mean that it is more fragile, all the major parts are the same as of our other machines. (with 10 year guarantee)
     
  10. speCulatius

    speCulatius Regular Member

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    500€ is what they sell it for, so not very competitive.

    I fear after my last discussions with @stringtechno , they don't believe that there's a lot I like about their machines, but I do. Completely inner supports would be great if kept simple and yielding enough space to work with inside the frame, and from what I've seen, they already have the best system (very few machines have inner supports as side supports though). Unfortunately, i have the impression that they're not even trying to improve it further and they seem to fear the comparison to 6 point machines, though there's probably nothing to be afraid of.
    True. Saying their machine is better and then saying the stringer on the other machine made a big mistake is not really good marketing. Also, if the stringer always strings at the same speed, same strings will end up almost the same everytime. Reminds me of my last discussion with him/her/them.

    At those prices, I don't want to be forced to use flying clamps. I need to use them at the moment and for those huge spaces at the bottom and top of Babolat rackets, that's not very comforting.

    An (ironic?) idea for the next test to prove that a machine is worse than another:
    Make the stringer string at -10 degrees (Celsius), then measure the tension and/or stiffnes at 30 degrees. The better machine will be used at the same temperature that's used for the measurements.
     
  11. speCulatius

    speCulatius Regular Member

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    For a constant pull machine, that's impressive!
    Nevertheless, that's fine if it works. It just made me laugh, because I wrote it before I saw the new message.
    Stiffer than others? Isn't there some plastic spacer in between? That's the first thing I noticed in your video and I didn't like the look of it.
    That's nice to have.

    Anyway, without the chance to use fixed clamps, it's not an option for me. Maybe cooperate with @Tennisman and build a mechanic constant pull machine with his new fixed clamps and bases. It can weight three times as much, would be fine. Maybe get some feedback on the gripper as well, looks slightly complicated, but I cannot comment without having tried it. Give one of those machines to @s_mair for testing (one for free for me would be fine, too), and he might buy it.
     
  12. s_mair

    s_mair Regular Member

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    6,5 kg is highly impressive. And regarding the clamps, it all comes down to what you're after. If weight is your priority numero uno, then fixed clamps are that first thing you need to cross off your list (along with an electronic tensioner...). A solid base plate will easily add another 5+ kg to the whole package. Plus the clamp bases.

    So if you're regularly on tour and want to have your stringing machine with you, this one seems to be a serious candidate. And with good flying clamps, you'll still end up with consistent results if you're used to it.

    And for the record, I'll most likely be spending my equipment budget of the next 3 years on that StringMaster, so I feel like I'm out of the test+buy thing for a bit.
     
  13. speCulatius

    speCulatius Regular Member

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    True, but they don't give me an option to put it on the list in the first place.

    Don't. It's heavier than the Superstringer and you're planning to string at tournaments, it doesn't give you a huge improvement and that T20 is your real love (only talking about stringing machines, still don't let your wife read this if you want to get the Stringmaster). I know I should be the one talking you into getting it, but is it really worth it for you or is it just the toy you want to play with yourself, because you know otherwise someone else will play with it? Think about all that effort you've put into making the T20 your machine. It might not be perfect, there might be someone/something better looking somewhere, but you know it's a great machine and you don't want to let it go just for some excitement. You'll never look at the Stringmaster the way you look at the T20.

    That's a bit off topic, but I can manage to get back to this one...

    @stringtechno, also talk to Tennisman about how to promote and sell your products using this forum, he seems to be some kind of genius regarding that. :D
     
  14. stringtechno

    stringtechno Regular Member

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    All contact with the racquet is plastic.

    [​IMG]

    Important is that we have a 5 point Direct support so the clamps at the top are only hold down clamps.

    I do not know about other brand tables but the same stiffness as our heavy duty aluminum table.

    The big advantage is that “normal” tables work on friction between the post and the table while on the LW table all the force works on the screw spindle.


    We launched 60 of these machines for tennis last year and the reason that we launch the badminton machine is because the feed back was very good. We use the string gripper already since 1985.

    All our other machines offer fixed clamps for badminton and tennis so no need to develop anything.
     
  15. stringtechno

    stringtechno Regular Member

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    I certainly owe an explanation about the slow and the fast string remark.

    I have to do a little bit of generalizing:

    Our experience about stringing accuracy with badminton stringers who contact us is not very positive.

    Most of them do not measure their final stringing result with a stiffness tester and many of them think that the accuracy of string job depends mainly on the accuracy of the tension unit.

    With this table I wanted to show that the result depends mainly on the stringer and the string.

    [​IMG]

    And because the major difference between strings is the time that is needed to develop all the elongation I believe that a lot of badminton stringers (who do not measure) THINK that they string accurately while the result is very different.

    To be honest I do not believe that stringers string slow strings slower than fast strings.
    But if I am wrong about this I will be glad to hear so.
     
  16. s_mair

    s_mair Regular Member

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    Currently, I'm still waiting for the badminton specific supports (hooray to German customs!), so there's no real hands on experience yet for the StringMaster. A major downside of it is definitely the boring black color, that's fur sure.
    So let's see what happens.

    Still, it's the first time that I come across the term of slow and fast strings, so maybe you need to do some further explanation on what you mean by that first. What I do know is that the differences between several tennis strings in terms of flexibility are a lot bigger than what I know from badminton.

    But to answer your question regarding different tensioning speeds for different strings - no, I do not change the pull speed setting on my WISE when going from let's say a 0.70 mm BG65 to a 0.65 mm Li-Ning No.1. Also, I keep the same pull-clamp-release rhythm and end up with a total string job time of around 25 minutes, independent from the type of string.
     
  17. speCulatius

    speCulatius Regular Member

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    This is exactly the attitude I was talking about and that I just cannot understand. "We've always done it that way, so there's nothing to improve." In another thread, I came up with several ideas to find out if there is something to be improved. It would probably have shown ways to improve it, too. All of them were rejected for the same reason. "We've always done it that way." That's death to all progress, to all improvement.
    Good to know, my memory was mistaken then. Still, they're not available for this machine. Furthermore, at the price point of your tabletop drop weight machine is comparable to the Stringmaster machines. Actually, yours is more expensive after taxes. You've probably always sold these fixed clamps, so why are they superior to the Stringmaster machine's clamps and bases (just an example of another new machine, feel free to compare it to any other machine)?
    PSX_20190302_150126.jpg
    Looks like all the force is going on plastic. Hard to believe that this is stiffer than other machines. Since it doesn't seem to influence the accuracy, it shouldn't be an issue. I was just surprised.
    I think you are referring to machines with moveable towers and only one kind of them, but I won't go into this. Like you said, there's a lot of factors involved in accuracy and consistency, the stringer being a major one.

    Anyway, I really think you're producing good machines, and I really appreciate that you're not only copying other machines and what's working for them. You act like there's nothing to improve when you do it and while I admire that confidence, I believe that there's always room to improve. Don't change for the sake of changing something, but I truly don't believe that your machines are perfect. I like the idea of having a string powered constant pull machine, no power needed, no no dropweight where the tension depends on the position of the weight (not too bad, but not perfect). I do like the idea of inside supports. Maybe that's why I'm trying to push you to keep improving. ;)
     
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  18. stringtechno

    stringtechno Regular Member

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    @SpeCulatis
    Nothing is perfect and the development of this machine took us 1,5 year, and I can assure you that there is not much to make more perfect. And we changed some details in 2019 compared to 2018.
    So it is really BS that we are not willing to improve.

    We follow all discussions on forums and we communicate with users to improve anything that we can. But we never get any complaints about our tension heads.

    This is delrin which is the best material to use for bearings it is important that bearing material can stand much pressure the stiffness does not play a role because it fits very tight in the steel frame .

    Are you an engineer?
     
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  19. stringtechno

    stringtechno Regular Member

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    @speCulatius
    To be honest it hurts a little when you say that we are not willing to improve. Therefore this pictures which shows the developments that we did in 35 years, excluding the last 2 being the Stringlab in the MS140.

    [​IMG]
     
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  20. stringtechno

    stringtechno Regular Member

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    @speCulatius

    You are quite quiet.

    Do you believe now that we spend a huge amount of time on development and do everything to make our products as perfect as possible?
     

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