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PostPosted: Thu Jan 03, 2019 4:32 am 
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Location: Malua Bay, on the NSW Nature Coast
I had a visit from a mate from Canberra today to see what more we could do with his Grinter flute. I'd fixed it up for him a few months back, but neither of us were at all happy with the tuning. If you tuned it for A=440, notes below A are dramatically flat (like around -50 cents). That takes a lot of work to overcome - it's like having a gear change in the middle of the register. The performance was weak too, especially on the low notes. We did find that setting the stopper out quite a bit further than normal helped, but it was a patch, not a solution.

Our purpose today was to knock up a shorter RH section to see if we could solve the very flat lower notes issue. And we did achieve that, and then settled down to some serious flute comparing. Tuning was dramatically better, but performance was still substandard. Jesse, listening to both of us playing one of mine and the Grinter observed that it was like the notes of the Grinter were "stuck inside", and "not getting out". We both agreed. They were veiled and weak, and the low D burbly. As a player, it sounded thin and dull to me. We went back to the original RH section. No better performance and worse tuning. I'm confident we've fixed any leakage issues, so it's not that.

It was late in the day that I noticed something I hadn't noticed before, and it surprised me. The LH section seemed unusually long. And that's what I'm hoping another Grinter owner can help me with.

When I measured from tip-to-toe of the LH section, I got 217.5mm, or 8 & 9/16". Can any other Grinter owners please check the length of their LH section and see if they get anything like that? I've checked all the likely originals I have here, and couldn't find any flutes that have a length like that, even quite early flutes like the Nicholson's and Potters (around 207mm). The longest I could find was a T. Lindsay's Improved at 215mm, and next a Geo Rudall made by Wallis at 211mm. And that's going back a long time! I'm wondering if we are dealing with an aberration.


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PostPosted: Thu Jan 03, 2019 7:22 am 
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Interesting. I have a Wilkes "Rudall model" here, and the left hand joint measurement from tenon tip to tenon tip is 211 mm. Notes below and above A=440 are in tune with the embouchure hole in line with the left and right hand tone holes.

Also, a R&R 5035, and the left hand joint measurement from tenon tip to tenon tip is 208 mm.
Notes below and above A=440 are in tune with the embouchure hole in line with the left and right hand tone holes.

Prehaps the Grinter you have is an early model. What year was it made? Maybe the long left hand joint is meant to compensate another part of the flute? Prehaps it's simply a mistake?


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PostPosted: Thu Jan 03, 2019 9:33 am 
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Interesting situation Terry, let me add to your consternation a bit:

I have 2 Grinter flutes, one keyed, one Keyless. I currently lack long calipers but I quickly eyeballed the lengths of both LH sections using a machinists rule. The keyed LH section appears to measure at 217-18, like the one you have, but the Keyless LH measured about 10mm shorter......

I don’t have the time, or even inclination, at the moment to measure all sections of both flutes to see what else might be different, perhaps at a later time I might though.

Regardless, both flutes play well and sound excellent, so that would seem to rule out LH section length as the problem.

Question, is the flute still in the hands of the original owner? If not, is LH section stamped with Grinter’s mark? Wondering, of course, if the section in question could be a replacement from another maker, Or possibly even a LH section from a “long” Grinter swapped mistakenly onto “short” Grinter?

The stuffy sound problem sounds like bore shrinkage to me: We’d often get old VH recorders back to the shop for servicing and find that some sounded just as you described. Initially I thought “wow, they’ve really improved VH recorders since that one was made, but then the head of the shop would go dig out the original reamers, hand ream them back to spec and BAM!!! Honking good tone and volume instantly back. One can only imagine how the original R&R’s, Prattens, etc sounded before years of bore
shrinkage, they must have been mighty indeed!

Back to Grinter, sadly I never made a set of bore measuring gauges, so I can’t send you any comparative measurements in an effort to test my theory.

Regarding section lengths, I did read somewhere that he made a change to the length of at least one section at some point, maybe around....15 or so years ago? I seem to recall the stated reason being that many people were having to play with the tuning slide extended unusually far. I’m not sure if that really makes any sense, but that’s my recollection of what I read at the time. I’m usually pretty good at remembering these sorts of things, but as I’ve gotten older I’m starting to think my memory is becoming less reliable, and this could certainly be one of those cases in point. At any rate, the examples I own certainly prove at least 2 different LH section lengths exist.

Ok, I gotta run, work to do, bills to pay, blah, blah, blah. Will be interesting to see what you end up making of all of this, Terry.


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PostPosted: Thu Jan 03, 2019 1:30 pm 
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Location: Hood River, Oregon, USA
I have a keyless Grinter flute here (key of D) which plays in excellent tune and sounds great. Its left hand section measures 217 mm.
The head, from the center of the embouchure to the bottom of the barrel, with slide closed, measures 160 mm. The RH section measures
134 mm, and the foot 148 mm. Note, however, that none of these measurements are acoustically significant because they include lengths
of tenons and sockets that overlap. They might help you figure out it you have parts from different flutes though. All of the parts (head,
barrel, LH, RH, and foot) are stamped with his makers mark.

It sounds to me like you still have a leak somewhere. If it is a keyed flute, I'd take an extra close look at how the pads are sealing, especially
the G# key, Bb and C key. I would also look at the spring strength. Its easy to pass the suck test and still have a leak which occurs when
positive pressure inside the flute lifts a key pad slightly when the key spring is a little weak. Given that the notes above A (inclusive) are
good, the G# key seems like a culprit, but other keys higher up may be the source.

Aside from that Maybe a socket leak that only comes in when the socket is splayed when the flute is together, or a tuning slide leak, or a
head liner leak, or a cork leak, or a fine crack somewhere in the body (probably LH section).?


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PostPosted: Thu Jan 03, 2019 5:09 pm 
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Location: Malua Bay, on the NSW Nature Coast
Paddler, that sounds like the same beast within a mm or two on each part. Thanks. Thanks also others.

Here's the intonation with all its original pieces, with stopper set at 19mm:

Image

As you can see, there's a dramatic "gear change" between G and A. And note the very high B4.

Now, when you report "plays in excellent tune", are you "playing it hard", actively forcing the tuning of the lower section up to pitch? If you approached it as "playing it in order to determine its natural tuning", would you get anything like what we found above?

I will check it again for leakages next time he's down this way, but I don't think that's likely. I did it up for him only a few months ago, and that meant going over everything thoroughly. I've just pulled out the notes I took when doing that. Among other things I'd noted:
- tested for leakage [that means under pressure with the Magnehelic Flute Leakage Detector]
- c key slow to close, Eb hardened and a bit leaky
- cleaned up slots and shaft of c-key
- replace Eb pad
- replace stopper, set
- play, check leakage. OK.
- check tuning. Odd!

I also checked that the pads were sealing this time, but didn't do a full leakage test.

The very long scale of the flute does explain the tuning we found. I make the scale length (c#-D#) 257.5mm. That about what you get?

Whoops, silly me, you have a keyless, so no D#. Loren, your keyed Grinter c#-D# length?


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PostPosted: Thu Jan 03, 2019 8:00 pm 
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Location: Hood River, Oregon, USA
I get much better tuning than that on mine without trying to play it in tune. Its tuning is very tight, on
par with that of my Olwell, and better than any of the flutes in my collection (antique or otherwise).

I have the stopper set around 21-22 mm from the center of the embouchure on mine. Setting it
further out than 19 mm should help to bring down some of those second register notes, get
the octaves closer together, and beef up the bottom end tone, but that doesn't explain the whole
pattern you have.

What ambient temperature were these tuning measurements taken at? Just curious about the slide
extension. It looks like it might be better in tune with itself with the slide extended more. That would
flatten everything, of course, but if there is a loss of pressure somewhere, finding and fixing that could
bring the lower notes up again.

At 70 degrees F I have about 10 mm of slide extension open to play at A=440 hz. In case it helps, the
C# to E (mine is keyless, so has no Eb/D#) distance is 202 mm, which is the same as my Olwell Pratten,
but longer than several other flutes I have here. To derive tuning from scale length you really need bore
profile too.

Have you tried playing this flute with one of your own heads (with tuning slide set so that you have
the same head length)? By swapping out heads you could start to narrow down the source of the problem
by a process of elimination.

Perhaps something your friend could do remotely is to take off the keys, plug the keyed holes with tac,
and see if that changes the way the flute plays. When I'm restoring antiques that is the first playable stage
they reach, and often they play great. Then keys are added and they play poorly until I've tracked down
all the leaks ... which can often take ages! If there is a significant improvement, then put them back one
at a time, testing again each time, to find the culprit.


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PostPosted: Thu Jan 03, 2019 10:43 pm 
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Terry McGee wrote:

- tested for leakage [that means under pressure with the Magnehelic Flute Leakage Detector]

Whazzat? Is this documented somewhere on your site? And if not, what is it?

As a recent convert to keyed Irish (or is it now simple system?) flutes, I'm never sure if the key cups are perfectly sealed under blowing pressure.


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PostPosted: Fri Jan 04, 2019 3:16 am 
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Probably not documented on my site except in a form I converted to be able to do other things. Mine didn't look quite like this but I think it's the same device internally:

Image

Essentially, it gently pressurises the inside of the flute via a flexible tube connected to that outlet at bottom left and controlled by the knob at bottom right. Before plugging it into the flute, you adjust the needle valve just above the pressure knob for a flow of 0.8 SCFH (Super Cubic Feet per Hour). When you plug it into the flute (with all the holes blocked up), the big Magnahelic dial indicates the airflow passing through the leaks. If it registers less than 2 for the entire flute, it's good. Obviously one aims for much less than 2.

Often, when I get a flute that really needs attention, they register 8. Like open air!

It's so sensitive, that when I hold a keyless flute with my fingers over the holes, I get a reading around 2. If I wet my fingers, it drops to zero. The gauge is measuring leakage through my fingerprint whorls.

Because it works on mild pressure, rather than vacuum like the suck test, it will unseat any poorly sprung keys.

That one can be seen at

https://musicmedic.com/musicmedic-com-leak-tester-full-size-machine.html

I wouldn't call it an essential tool, but it's lovely to have it!


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PostPosted: Fri Jan 04, 2019 9:02 am 
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Thanks Terry, that's a cool device! And of course I want one now, except at that price it's obviously intended for a serious woodwind repair or maker shop. I'll have to make do with taping down individual suspect key cups to see if there's a leak when blowing the flute.


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PostPosted: Fri Jan 04, 2019 9:06 pm 
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I had a d whistle from Michael that played horribly flat when I got it. When I enquired, it came to light that he'd recently changed designs, and the head was from the earlier and the body from the later, or vice-versa. So there would be precedent for pieces to get mixed up.

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PostPosted: Fri Jan 04, 2019 9:32 pm 
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chas wrote:
I had a d whistle from Michael that played horribly flat when I got it. When I enquired, it came to light that he'd recently changed designs, and the head was from the earlier and the body from the later, or vice-versa. So there would be precedent for pieces to get mixed up.


Yup, exactly why I brought up the possibility in my previous post: There was absolutely a precedent, for flutes as well as whistle’s.


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