Crank machine vs Electronic, difference in tension?

Discussion in 'Badminton Stringing Techniques & Tools' started by knielsen, Aug 31, 2014.

  1. knielsen

    knielsen Regular Member

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    Hi,

    I just received a new machine, its a Siboasi SS-901, originally for tennis but im using it purely for badminton rackets.

    I got the machine for free, in exchange for stringing some rackets for a shop, so i really cant complain that much about the quality, so lets make that one float (i know its not the best).

    What im wondering is that on my old crank machine, i would string my rackets to around 30 lbs, and the tension would be rally good, nice sound on the strings as well..

    On the new machine, it feels atleast 6-8 lbs lower, its not nearly as tight, not nearly as high pitched even with the same string..

    What i initially thought was that the machine didnt string it at the right tension, so i used my baggage weight which is digital to measure both in KG and LBS, and was more or less accurate, it varied about 1 LBS or 0.5KG, which i believe is within the norm (not entirely sure?)

    So 30 LBS would be 29-31 LBS, roughly..

    I then measured with the same weight, the same way on my old cranck machine, and it showed the same, with a slighty lower variation so its pulling with the same tension..

    I then thought back to when i was using a Yonex ES5 Pro for stringing my rackets, i had the same problem, i had to up the tension with 5-7LBS to get the same feeling in my rackets, which is a problem when im at 30LBS in the first place!

    Also, do i need to wrap the string around the little metal piece in front of the piece where i put the string in?

    765781208_590.JPG

    Im not doing that, from my testing it seems to be a tad more accurate when im doing this, but im not sure it will make any real difference other than slow down my work.

    Can anyone give any hints to this? Is it due to the electronic machines not stretching the strings the same way? When im doing it on the cranck machine i can hear the BG80 stretch and make little screeching noises, this doesnt happen on the electronic machines..

    This is kindda frustrating :D

    Btw, typos are free;)
     
    #1 knielsen, Aug 31, 2014
    Last edited: Aug 31, 2014
  2. craigandy

    craigandy Regular Member

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    First off I suppose you could easily check if the end result is actually the same as when you are using the crank. There is an app called carl tune that measure frequency only but is a good comparison of the end result. Use the same racket and same string but use the two different machines, strum the string at the end and see if it matches. If the end job of the electronic machine is actually lower you could check to make sure there is no string slip from the tension gripper and also the clamp grips.(use marker pen on the string)
     
  3. knielsen

    knielsen Regular Member

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    Hi,

    Thanks for your suggestion, but i dont really need an app to check the tone, it is alot different..

    It is clearly that its not the same tension, which is what makes me wonder why it behaves like this..

    I would expect that it would be the same, if the calibrator shows the same tension, what i noticed this morning when i was packing my gear, was that the newly strung rackets, have the same "ping" as the racket im using right now, which has been used for about 2 weeks, which in the end lowers the tension quite a bit.

    No other ideas as to why the sound/feel is different?
     
  4. R20190

    R20190 Regular Member

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    Yes, best to wind the string around the spindle (or whatever it's called). It will help prevent the string slipping.

    Do you have a digital scale? They are quite cheap now, you should be able to pick one up for around $5-$10. Use it to calibrate the machine and check that it is giving you the tension you had on your crank.

    I suspect that your crank machine may have been out of calibration, perhaps giving higher tensions than you dial. So best to check it properly.

    Clean the jaws of the gripper with something like rubbing alcohol and make sure it is not slipping. Instead of marking the string, I usually just put my finger on the string at the end of the gripper and feel for any movement.
     
  5. craigandy

    craigandy Regular Member

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    I see.
    Well, if the end result is different and both devices are pulling the same tension and not going down in tension before you clamp off and you are using same knots etc, the only thing I can think is the clamps may be slipping, did you test them by marking the string then pulling tension on with string clamped to see if they are slipping? Other than that, I dunno sorry.
     
  6. knielsen

    knielsen Regular Member

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    Im at a loss here as well, it should be the same..

    I will try and fiddle around with it today and see if i can make some adjustments, its a brand new machine so im still getting used to it so things might be different at some points.

    R20190 i do have a digital scale, and it shows that the crank machine hits the right tension, if i set it for 13kg, it will string it 13kg + - 200Grams, the electronic machine is about the same but + - 4-500 grams, i guess that its not too accurate due to the fact that its a lowend machine..

    And honestly, i got it for free, so cant really complain about it, i just need to adjust to using it, if the rackets are consistently about 1KG (2LBS) lower in the end i will just up the tension a bit (and hope the rackets can hold)..
     
  7. craigandy

    craigandy Regular Member

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    I am no expert but think about it this way, its no rocket science. In all stringing machine there is something that pulls the string and something that holds the string, until you pull it again. As long as the racket is bolted in place, if there is an 8lbs difference then one of these things must be the problem.
     
  8. Mark A

    Mark A Regular Member

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    Precision is preferable to accuracy - if your tensions are 2 kg below the target, but within 0.2 kg of each other, that's a lot better than the other way around!

    You either recalibrate it, or just add/subtract the difference.
     
  9. knielsen

    knielsen Regular Member

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    I will do this later, just trying to work out how i can calibrate this machine, no easy way from what i can see..

    I will give it a work later today, and hopefully i can find out why this is happening, or its just me thats messing up, who knows!

    I hate the feeling about doing it wrong, when im consistently doing 20-30 rackets per week, if im doing something wrong then that terrible! :D
     
  10. R20190

    R20190 Regular Member

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    Well said that man!

    With crank machines, some can be very inaccurate in that they don't give you the tension you dial. But providing it is still precise enough and consistent enough, you can compensate for this by dialling a bit more or a bit less to get what you want regardless of what it says on the scale.
     
  11. Mark A

    Mark A Regular Member

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    The Siboasi rotatry pullers have an adjustment hole into which a hex key fits - you pull tension with your scale, then adjust this screw to increase or decrease the displayed tension to match it.

    Don't know if the linear pullers have the same feature.
     
  12. knielsen

    knielsen Regular Member

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    Thanks Mark A!

    I have been giving it a run tonight, and think i might have found the culprit, the tension in KG is way off..

    Set it to 14kg, it will string at about 13kg + - 500Grams..

    Set it to LBS instead, and its much more accurate, 29lbs comes in around 28.6-28.7..

    Also, the conversion is 1LBS = 0.5KG, but not if i choose 14KG, which is what i normally use, that step is actually 3LBS..

    From 30 LBS - 33LBS is displayed as 14KG, 34LBS is then 14.5KG, 35LBS is 15.0KG.

    Im glad i caught that since 30LBS is ~13.5KG, and its off by 0.5KG im actually stringing 1KG lower than i should..

    I will however try and look for the calibration screw, however i have no idea if its a linear puller or rotatry puller :D
     
  13. Mark A

    Mark A Regular Member

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    It's a linear - it goes back and forwards. The rotary ones go round and round.

    http://www.arfaian.com/download/EN_P103.pdf

    This may help - it says there is a calibration screw at the rear of the puller, but again, this is the rotary version.
     
  14. knielsen

    knielsen Regular Member

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    So after a while, i think i might have adjusted to this machine, just bumped up the LBS untill it felt around the same, rackets are holding up fairly well..

    Although, this might be due to the way its pulled, but the tensions drops quite a lot more when strung on this machine, almost like its missing pre-strech or something, can i do anything here?

    Can i do "my own" pre-strech to prevent tension loss that high? At the moment it feels like it drops at least 1-2KG after a week or so..

    Can someone shed some light on this?
     
  15. Mark A

    Mark A Regular Member

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    Loop the string around a door knob and pull it as hard as you can a few times - you will feel the string stretch, and then start to resist. If you do not do this, the string will stretch inside the racket, which is where your tension loss comes from.

    I always do this even when using electronic prestretch.
     
  16. knielsen

    knielsen Regular Member

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    What would happen if i just string it at more LBS? Never had this issue before, in my crank machine the string tension loss was almost zero, and the feeling was very different compared to this electronical machine..

    I have already bumped tension to 32LBS from 30LBS, but its still dull, the cliing sound isnt there at all in the same way :( Also, after a few days, it feels more like a 25-27LBS stringjob, which is just too low for me!

    Would it be possible to just bump the tension to 35-36LBS and hope it would settle in at around 32LBS?
     
  17. craigandy

    craigandy Regular Member

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    Maybe you should check the machine with your digital scale at the higher tensions that you string at. I read last time you tried it at 13kg (28.5lbs). Why don't you see what the scale reads when you set it to 30lbs, 32lbs etc. Did you get round to checking your clamps?
     
  18. knielsen

    knielsen Regular Member

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    I will test it once again today..

    I have looked at the clamps, they do grip the string fine and doesnt allow it to slide, i check this after each string to make sure its not slipping.

    One of them got a little wickle room, so it will move about 1-2mm, it seems that the clamp doesnt fit 100% into the arm (if that makes sense).

    Where can i buy new clamps that might fit this machine?
     
  19. dandipower

    dandipower Regular Member

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    the manual crank machine cant do standardization so each string line has some different tension and different stress too, strings bed principles as same as trampoline if each string tension not homogeneous, impact feeling will be harder, ..........but the electronic constantpul is more precision and able to make each tension similar and its feel softer, just a newbie oppinion (CMIIW)
     
  20. dbswansea

    dbswansea Regular Member

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    My new ECP certainly doesn't feel softer than my crank.
     

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