Hip to be Square

Discussion in 'Manufacturing and Construction Techniques' started by pete, Oct 4, 2010.

  1. pete

    pete Brassica Oleracea Staff Member Administrator

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    First, your obligatory 1980's remix link: http://www.youtube.com/watch?v=LB5YkmjalDg

    Anyhow, I was thinking the other day that I hadn't seen instruments made with square tone holes. I wondered why, as one would assume that toneholes could be made to a more accurate specification -- at least from a math standpoint: no need to worry about how exact your measurement of 22/7 is.

    Well, I do like pi. And pie. Apple or cherry, please.

    I Googled, and I see that square tone holes have been done before ... on flutes. Check out http://artsspectrum.blogspot.com/2009/08/flutes-with-square-holes.html (and see http://www.lopatinflutes.com for more and larger pics).

    Now, I know a couple of y'all have dabbled in instrument design. What do you think? It seems that this is proof-of-concept that, at the very least, a flute doesn't have to have round tone holes. Hey, according to this, there was proof-of-concept for flutes, oboes and clarinets way back in 1888.

    I bet it would look great on a sax. If it works ....

    BTB, I have seen square keywork before, particularly on low recorders and other 18th century and earlier woodwinds and double-reeds. I can understand why modern keywork generally isn't square: you're saving appx. 22% of metal area using a circle, rather than a square. i.e. "It costs more."
     
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  2. Steve

    Steve Clarinet CE/Moderator Staff Member CE/Moderator

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    (parody posting)
    The biggest issue one has is in the way of sound waves

    We all know round holes create a nice flowing Sine wave.

    Now square holes create a Square wave.

    Square waves have issues in that they don't fit into round ear tubes ....
    and thus cause headaches
    so square tone holes have never caught on ......

    ..... just joking guys ......
     
  3. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

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    Square tone holes don't really make any sense acoustically--what Lopatin says is acoustic technobabble. In addition, square holes are structurally weaker, and edges always create turbulence problems. Simple is best. Normal round tone holes...
     
  4. jbtsax

    jbtsax Distinguished Member Distinguished Member

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    I find especially interesting his observation that the straight edge of the square tonehole more accurately represents the straight edge of the end of the flute. The other idea I like is that the square tonehole allows for a larger volume to vent the note.

    One cannot argue with the inventor's credentials as a professional performer on the flute, nor fault the recorded examples of him playing the instrument. When one looks at the prices of his hand made instruments, it is understandable why the square tone hole flute is not more widely accepted.

    Whether the concept has acoustic validity or not, I say the "proof is in the pudding".
     
  5. DavidW

    DavidW

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    I figured it was due to lack of availability of square drill bits :D
     
  6. SOTSDO

    SOTSDO Old King Log Staff Member CE/Moderator

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    Well, there are ways to "drill" a square hole. But they are cumbersome at best, and would require great adjustment to function with standard musical instrument manufacturing.

    First, let's put aside the combination drill/square chisel bit tools that are available. While they would work in soft wood (like a door frame), getting a clean cut on a hard wood (such as those used in instrument manufacture) would be next to impossible.

    The way to get a square hole is to drill a pilot hole, and then use a series of increasing sized broaches to slowly but surely "ram" the hole into the wood. This is done in metal machining all of the time, and similar techniques would work with hard woods. (Instrument manufacture is more like metal working than it is like standard woodworking.)

    Broaches are used with specialized machinery that regulates both the depth of the stroke and the return of the tool without dragging on the machined surface. To cut a square tonehole, the pilot hole would be followed by bits that would first open a rectangular hole, and only then finish the remainder of the "square" shape.

    If anyone wants to know about other, obscure metalworking techniques (like broaches and bulldozers and full revolution power presses), feel free to ask...
     
  7. jbtsax

    jbtsax Distinguished Member Distinguished Member

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    Most flutes nowadays have "extruded" or "drawn" tone holes in which a circular plug is pulled up through the wall under great pressure using some type of jig. The edges of the tonehole are then cut and (supposedly) leveled. My sense of mechanics fails me on this next question. Would it be possible to extrude a square tonehole using a similar technique????
     
  8. SOTSDO

    SOTSDO Old King Log Staff Member CE/Moderator

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    You would be able to draw a square through a tube, but like drawing a circular object through a tube, the height of the "cube" that would result from this would still be uneven, with the edges "down" on the tube being lower than the portions "up" on the tube.
     
  9. pete

    pete Brassica Oleracea Staff Member Administrator

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    In the case of the flutes I mention, above, the tone holes look obviously soldered, so I'd assume that the tonehole "chimney" is made completely separately.

    In any event, they look rather interesting. Anyone here actually try one?
     

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