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Using string for the movement of stops, keys, couplers etc.

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  • Using string for the movement of stops, keys, couplers etc.

    Hello all,

    I am quite new to the organ world and am wanting to dabble in building one myself, a small piece with only 3 or so stops (and ranks). I was thinking of perhaps making one rank from wood (perhaps a stopped diapason?) from wood and the others from paper using the method detailed by mark wicks here, as i am relatively inexperienced in woodworking in general, while still having done some work at school. However, I also had the idea of using string or strong cord for the purpose of carrying the movement from the keys and stop knobs etc to the wind chest and stop boards. This seemed to me to be a simple way of avoiding the fiddly work of making all of the mechanisms to do this out of beams, rollers and wire etc, instead being able to run a length of cord from the key to the wind chest through a series of pulleys and tie it at each end.

    Is there a specific reason that this is not already done? It seems quite likely that it was not done when building say a large church organ because the cord would be liable to stretch or be eaten at by mice and rats, thereby meaning that the organ would have to be serviced much more often than practical. None of these reasons really apply to me, however, as I am not looking for my organ to last for hundreds of years, and now with stronger nylon threads and suchlike, as well as me being available to maintain it almost constantly, I do not see any particular reason which would not let me use this as my mechanism for stop action etc.

    Please correct me if i have made any glaring errors, and if you have any suggestions or feedback on any of the rest of the organ detailed in the above link, please feel free to reply with that as well. I am thinking of following the design for wind-chest and the rest of the organ quite closely from that link and only changing the mechanisms to cord-based.



  • #2
    String will not provide necessary feedback to the performer that their actions have been received by the chest pallets unless some kind of dual string mechanism that could transmit forces two ways could be devised. Sounds unnecessarily complex to me.


    • #3
      A little bit of stretch over a relatively long distance will quickly overcome the travel of the keys. You'll need some kind of complicated tensioner for each cord.

      Imagine trying to fish a new cord in when one breaks.


      • #4
        Changes in direction require pulleys, pulleys will require using tensioners. Tensioners will add weight. Mice will nibble small and large instruments alike.


        • #5
          It has been done, actually. I know of one builder (now deceased) who built a few small mechanical-action organs that used nylon string to pull the pallets open. The runs have to be relatively short. String (as others have pointed out) does stretch, and pulleys are necessary to convey the key motion to the pallets. the pallet springs will provide sufficient force to keep the string (relatively) tensioned, but with no mechanical advantage (if the key moves 6 mm, the pallet will also move 6 mm (until the string stretches), so pallet sizing becomes critical, particularly in the bass registers.

          Rick in VA


          • #6
            String does stretch, but there are non-stretch alternatives. I ring bells, and the bells that I ring on just got new ropes a few weeks back. The top ends of the back four bell ropes, all for bells weighing in at over a metric ton, are made of Ultra-High-Molecular-Weight Polyethylene (brand name Dyneema), which is a zero stretch (well over seventy feet of rope mind you), and stronger per weight than steel. I'm not sure if you would be able to acquire it in the diameters required to make an organ action, but it would be worth investigating.


            • #7
              They use dyneema (and some other high-strength) strings for stunt kites. It is very stiff and strong. It can be a little finicky to tie because it is slippery. Often, the string is threaded through a nylon sleeve to make it easier to tie (and to keep the knots from sliding or coming undone).
              Home: Yamaha P22 and a modified Allen ADC-4500 ... for now.
              Church: Allen MDS-5
              Files: Allen Tone Card (TC) Database, TC Info, TC Converter, Chorus/Mixture TC Generator, ADC TC Soundfont, and MOS TC Soundfont


              • #8
                Dyneema ... dunno ... sounds expensive. Can't tie knots in it? Requires nylon sleeving? Thin gauge aluminum rod has been around forever. Easy to work with ... string I actually get. But if it can't be string, for all the reasons mentioned. Then I can't see that going to some high tech textile is an alternative. If it ain't broke ...


                • #9
                  15 bucks on Amazon seems pretty reasonable to me. Why fix it if it ain't broke? Because maybe there's a better, cheaper solution, and that's how innovation works..


                  • #10


                    • #11
                      My home organ uses very fine steel cable between the keys and the pallets. This is very fine stranded flexible cable covered with thin plastic as used in model airplanes. It is about 0.8mm overall diameter. Look for "control line model airplanes".

                      The keys are about 500-600mm long and pivot at the far end. The pallets sit straight above the keys and the cable runs straight between them. No need to tension anything, no stretch. With an organ that small you don't need very wide channels so you can keep them narrow enough so you won't need rollers.

                      It is even used in large organs. The organ in the cathedral in Brussels uses "wire" between the main part and the 2 separate pedal towers.