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Is there a way to measure string tension that the average person can do?

Discussion in 'Strings [BG]' started by shoulderpet, Dec 5, 2017.


  1. shoulderpet

    shoulderpet

    Sep 24, 2015
    Hi
    Was wondering if there is a method of measuring string tension that the average person can do, most string companies are very secretive about string tension etc and would be useful to have this information.
    I read somewhere ages ago that you can snip off 1 inch of the string weigh it and multiply it by 34 (or 30 if short scale) and this will give you the tension of the string but I cant remember where I read this and is likely not accurate
     
  2. HaphAsSard

    HaphAsSard

    Dec 1, 2013
    Italia
    The formula to calculate tension in pounds for a given scale length in inches (L) and pitch frequency in hertz (F) from the weight, again in pounds (well, decimals thereof), of an inch of string ("unit weight", UW) is the following:

    T (Tension) = (UW x (2 x L x F)²) / 386.4

    As for the practicalities of weighing a section of a string to obtain its unit weight:
     
    Last edited: Dec 5, 2017
    Klonk likes this.
  3. GHS is one of the few companies that actually publish tension numbers.

    CLICK HERE to download the GHS Tension Guide, courtesy of @Jon Moody.

    Refer to page 2 of this document for info on how to calculate tension.
     
  4. shoulderpet

    shoulderpet

    Sep 24, 2015
    Thanks, so all i need to calculate tension is a set of scales and a calculator?
     
  5. Gravedigger Dav

    Gravedigger Dav SUSPENDED Supporting Member

    Mar 13, 2014
    Fort Worth, Texas
    I assume the calculation is for standard tuning. I think down tuning would change (lower) the tension.
     
  6. Klonk

    Klonk

    Apr 28, 2011
    Norway
    Which tuning you choose is already in the model, isn't it? It says frequency..
     
    michael_t and HaphAsSard like this.
  7. The info in the GHS Tension Guide, posted above, would allow you to calculate according to pitch. It can apply to alternate tunings.
     
    Gravedigger Dav likes this.
  8. HaphAsSard

    HaphAsSard

    Dec 1, 2013
    Italia
    The formula in the GHS tension guide is the same I posted above.
    Correct. If you input a different value for 'F' (e.g. 36.708Hz for D1 instead of 41.203Hz for standard E1), you get the corresponding (in our example a lower one) tension result for the given string (whose unit weight is provided by the manufacturer or obtained through...weighing the string) at the new tuning.

    EDIT (sorry, forgot to mention) -
    Id. for different scale lengths: you put in, for ex., 30 instead of 34 as the value in inches for 'L' and Bob's your uncle.
     
    Last edited: Dec 6, 2017
    Klonk and Gravedigger Dav like this.
  9. lz4005

    lz4005

    Oct 22, 2013
    If you wanted to do less math and not destroy the strings in the process you could set up a spring scale rig and just measure it.

    One tuner, a couple of bolts to stand in for the nut and bridge saddle and something like this that measures in the 20 to 60lbs range on the ball end and you'll be able to measure the pull directly.

    AC137478l.
     
    michael_t likes this.
  10. shoulderpet

    shoulderpet

    Sep 24, 2015
    Another consideration has just occurred to me, do you need to weight the strings in their full uncut weight or can you find the tension by weighing the strings in their cut state ? (most people myself included will cut off the excess with wire cutters)
     
  11. Jon Moody

    Jon Moody Commercial User

    Sep 9, 2007
    Kalamazoo, MI
    Manager of Digital Brand Development and Product Development at GHS Strings
    The excess that you usually cut off is what goes around the tuning post, which is not a factor in string tension. You need the full diameter of the string.
     
  12. shoulderpet

    shoulderpet

    Sep 24, 2015
    Ok so when weighing do you need to take the excess into consideration? i would have thought you would need to only weigh the portion of the string that makes up the scale length (so not the excess) of course i may and probably am wrong in my assumption
     
  13. Jon Moody

    Jon Moody Commercial User

    Sep 9, 2007
    Kalamazoo, MI
    Manager of Digital Brand Development and Product Development at GHS Strings
    That's exactly correct. Only the "full diameter" of the string, between the nut and the bridge saddle is what is used.
     
  14. shoulderpet

    shoulderpet

    Sep 24, 2015
    Ok thanks, now i can see why people refer to tension charts rather than butchering there existing strings
     
    Nev375 likes this.
  15. Certainly the internet has an on-line calculator for that somewhere?
     
  16. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    You’re going to need a pretty sensitive scale.
     
    Honch likes this.
  17. http://www.daddario.com/upload/tension_chart_13934.pdf
     
  18. Honch

    Honch Guest

    Sep 7, 2006
    You can't use a regular spring scale. Both D'addario and GHS lists tension. I think this is a weird and blunt way to measure anything really. People are so often mixing up stiffness with tension and so on. On top of all this I would love to have a 3 digit apparatus that measured in NEWTON which is considerably more to the bone.

    However, there's one tension from behind the bridge towards the ball end, depending on angle, and the real PRESSURE downwards exists on the bridge saddle where the string presses force downwards at the saddle. It's under or "IN" the saddle I would love to "weigh" or "measure" things. Same thing at the nut. Would get different readings depending on the angle from the nut towards the tuning peg. There too I would love to have individual micro-scales (!?) under the nut, to keep track of how much down pressure there is. It's very elusive and shady to measure tension any way on bass guitar strings. If it was possible to get a spring scale with small clips on IN TO THE MIDDLE OF THE BALL END HOLE of a string, that would cause - too - excess mass and add weight to the total mass of the strings measured. It would be hard to calibrate. I don't know if there is some "tare" on such spring scales. But how that should be carried out while strung on any bass beats me. The tension given by companies are at best a theoretical estimate stemming form physical calculations. I would love to have at least 2-3 decimals to the tension measurement of any bass guitar string, or regular guitar string. It's too delicate. Because it's the same tension added with the notion "the rope around a corner".

    main-qimg-3eeb6e110ab3eb4089eb618b31ee598d-c.

    and that capstan load too, which is at the bridge saddle. No matter that you have a rolling saddle bridge, but some actually do.

    Capstan_force_diagram_4.

    I e the "hold force" relation to "load force" when a string passes a cylinder or in bass case a saddle at the bridge, or at the nut. So measuring general tension on strings is a very blunt tool to me.
     
  19. lz4005

    lz4005

    Oct 22, 2013
    Very interesting.

    So, go with me here. If we had a test bed instrument, let's say very similar to a P bass, but with an extra 18" between the nut and tuning peg. Enough room for a spring scale. And we make the break angle over the nut as minimal as possible. Less than you would ever have on a functional instrument, just enough to get a good reading on it being in tune. How inaccurate would it be, in theory?
     
  20. Honch

    Honch Guest

    Sep 7, 2006
    You could do it slightly better on a headless Steinberger headless bass or similar. With double ball end strings. I am not saying the theory that GHS or D'addario lists with tension is utterly wrong, just a little too blunt. But how could you prove them? Or disprove them? Stringing it up, tuning it and go "hey, its nothing near 8 lbs!!! I want my money back. There are several points along the strings length that "stops" you from measuring tension correctly.


    It's here the culprit lies. As well as back at the bridge, but it's enough with that one end has no or as little break angle as possible. The thing is these charts of tension is correct between two points of the string, and if you only had two stop or break points along the string it would be better off. It comes closer on a headless instrument with double ball end strings, but people forgets that between the nut and tuning peg, or behind the bridge and ball end there's also a "scale", even if it's one inch, and totally unusable for musical purposes, but make no mistake that it induces a lot of tension and stress on the string, in total.

    So I wonder how a spring scale should be used, on a regular bass, even a Steinberger headless one, if you should prove or disprove the manufacturers listing of tension. For example it is my opinion that bridge saddles for the low B-string on a bass shouldn't be just wider to accomodate for huge string gauge, but larger still in dimension that a larger portion of the string behind the witness point resides on the "capstan" (see above) before it goes off in the air again. You need longer part of the string to get properly damped. I would love to see this up at the nut too. You don't do anything to tension on this only to take the load off at a too narrow point on the string. The string gets damped more properly if it resides on more mass at the end. Of course you can buck this with greater angle, but the metal fatigue sets in sooner.
     

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