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I often get my fifth hole off center when I want it centered. If it is slight I can adjust it but if more than a couple of millimeters it will not be resolved.
I am interested in other flute makers experiences, techniques or tricks in getting hole 5 centered, particularly with flutes short enough that holes 1-4 are also centered and may be used by left or right handed players.
FYI...I am blind and make my flutes by feel with the use of a talking tape measure, so "eyeing it up" is not an option. When checking the position of my drill-press, I check with both left and right hands alternatively as they both give me a different impression of 'centre', so I compromise between them, plus the plane of the blow edge.
Kel.
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Seems to me that using the plane of the blow edge would be key here. I'd consider creating a small fixture that would either lay on your drill press table (or fit in your table vise, whichever) which would register the flute using the plane of the blow edge. The part that fits against the blow edge could have an adjustable angle to fit any small variances among flutes.
If the plane of the blow edge is held perpendicular to (or parallel to, depending on how you visualize this) the drill press table, the 5 hole will always be drilled in the center of the shaft.
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edosan wrote:
Seems to me that using the plane of the blow edge would be key here.
Hi Kel,
I know you're a ceramicist. What about rolling up a 'bb' sized 2-3mm diameter piece of clay, press it on the 5 hole spot, then bring the flute to your chin to blow and study how that feels in relation to the thumb and the utaguchi. Repeat, if necessary and then you'll have a little mark of clay. -kerry
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OK, here's what I am currently doing, first I calculate and measure the hole distance from the blow edge having the culm front side down in a cradle. I feel the blow edge plane, that is the bevel/wedge plane from side to side to determine that it is facing down. With the tape against the culm I estimate the centre and mark it with an awl, leaving a 1mm hole.
I then place the culm in a smaller 100mm cradle, bring the awl hole up to the drill point, then pull the press down to the table. The drill is turned off at this time and I am holding pressure on the press handle. With the culm now being held down I again check with both hands alternatively that the culm is facing down as accurately as I can, I will also feel under the culm to the upper holes 1-4, again with both hands alternatively, to relate them to the downward facing plane of the blow edge. Now I should be able to presume the front face is pointing down and therefore the rear is pointing up. I have the length marked I just need it to centre from left to right of a culm that is usually neither perfectly straight nor round.
Again using both left and right hands I feel to estimate the drill position that it is equal distance from both sides of the culm. I am using an 11.5mm drill bit. When I think I have it right I switch on the drill and cut the hole.
So Kerry, I am in a sense doing what you suggest by marking with the awl, this is not always my final position, once on the press I may well withdraw the drill bit and move it sideways if I am not happy with how it feels in that original hole.
And Ed, if I am seeing your idea, what you are suggesting is a tool to assist having the front face accurately pointing down. This is a good idea, the design of this tool has to be very simple. But I can't see how it yet will give me that centre point that the drill tip has to enter.
Maybe I am missing something ?
Kel.
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The bamboo circumference is often uneven and there may even be a slight curve/bend between the utaguchi and the fifth hole. When I have picked the position of the hole and drilled in the same session, I have sometimes been unhappy with the result. I test by feel mostly and place a small round sticker on the spot. I then return several times to check before drilling.
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Karmajampa wrote:
And Ed, if I am seeing your idea, what you are suggesting is a tool to assist having the front face accurately pointing down. This is a good idea, the design of this tool has to be very simple. But I can't see how it yet will give me that centre point that the drill tip has to enter.
Maybe I am missing something ?
I see your point: it's still possible, even though the front 'face' of the culm is accurately DOWN and perpendicular to the drilling axis, you could still drill the hole off-center into the shaft. Seems to me that if, after using the suggested simple jig, you could ascertain the highest point (tangent) of the shaft, and place the drill point there, no?
I also like Kerry's idea of placing the point by what feels right, rather than geometrically, either by using a bit of clay or a sticky circle, as it's the right 'feel' that will matter anyway in playability.
eB
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That 'top point' you refer to Ed could be 2-3mm wide which will be noticed if offset, by the thumb.
'Feel' is good, and the more flutes I make the better they come out. Any tool I use has to be non-visual, even that piece of sticky paper is a visual guide.
Even using Kerry's spot of clay still does not give me the exact centre for my drill point.
It may surprise some how much difference 1mm offset feels.
Fun huh !
Kel.
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Karmajampa wrote:
It may surprise some how much difference 1mm offset feels.
Fun huh !
Have you actually experimented by moving the center around by 1mm on a given flute, or are you referring to how much difference a 1mm offset feels across several flutes, each likely having a variety of different 'feel' characteristics?
Just wonderin'....
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Ed, as an example , my Monty 1.8 has all five hole centred, so can be played by a right hander or a left hander with no feeling of hole five being offset, this is my standard for the feel. I have just made a 2.4 for a right hander. I intended hole five to be centered, or if anything biased to the left. It ended with a very slight bias to the right. With index finger on hole four using either hand I can feel the bias. Because it is so slight I can adjust this feel by shaping the hole.
I am now working on a 1.8 an will try drilling hole five with an 8.5mm bit instead of the larger 10.5 or 11.5 then do any correction with files. I expect the note to be flat but this may be a practical way for me to asure hole five is eventually centered to feel.
Still curious how flutemakers approach this issue.
Kel.
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Gotcha.
Here's a thought, but it probably only makes sense for a sighted person (if that...):
Assuming you're happy with the centeredness of the front holes, a strip of paper may be wrapped around the shaft at hole four, thereby ascertaining the circumference of the flute at that point by marking the paper where it overlaps. The circumference on the paper is then divided into two, and that resulting dimension, when placed on the centerline on the front and wrapped around the shaft to the back, will locate the center of the flute on the five hole side.
Perhaps you can somehow adapt this notion for your own purposes.
eB
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Good thinking, fiddly, and I think it would require sight, I have previously considered a string line from the centre of each end, still fiddly.
Just did the 1.8 using the smaller 8.5 bit. Yes the pitch was flat, the hole biased to the right, which seems to be my pattern, and I take this into account also. But not too much shaping to bring it back to center, and correct pitch, so I may try this again. If I could see what I am doing I would like to try burning each hole.
Pitch is not so much of a problem, I am working on tone balance these days.
Kel.
Last edited by Karmajampa (2008-08-31 02:32:47)
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