Re: [Harp-L] Lowering the reed pad and reed aerodynamics

[Winslow Yerxa <winslowyerxa@xxxxxxxxx>]

Lowering the reedpad itself by lowering the corresponding part of the reedplate surface has been tried by a few people, notably Jerry Murad, who described it to me circa 1996.

The potential benefit is to be able to place the entire length of the reed, especially the root (where the vibrating length of the reed joins the reedpad) as close as possible to the surface of the reedplate (and thereby the slot. Pressing the root of the reed down with a fingernail or a tool still does not eliminate that tiny downward curvature from the root off the reed (which always seems to be significantly higher than the ssurface of the reedplate) to wherever your thumbnaail cam press it.

The potential problem that this can introduce is to place any portion of the vibrating length of the reed below the surface of the slot.

So removal of metal from the reedplate in the palce where the reedpad is seated would have to be done precisely enough to lower the reedpad just enough but not too much, while creating a surface that will not put the width of the reed out of parallel with the surface of the reedplate or prevent the reedpad from making full contact with the surface of the reedplate. That's a job beyond my stone-tools approach, but a good machinist or savvy user of computer-coltrolled milling equipment could probably manage it after making some very fine measurements.

Winslow

Winslow Yerxa

Author, Harmonica For Dummies ISBN 978-0-470-33729-5

--- On Sat, 1/3/09, Robert Coble <robertpcoble@xxxxxxxxxxx> wrote:
From: Robert Coble <robertpcoble@xxxxxxxxxxx>
Subject: [Harp-L] Lowering the reed pad and reed aerodynamics
To: "Harp-L" <harp-l@xxxxxxxxxx>
Date: Saturday, January 3, 2009, 7:11 AM

Rick Epping gave some absolutely wonderful information aboutembossing and
chamfering reeds.One of his techniques is to lower the reed into/toward the slot
atthe reed pad/heel, using a fingernail to press down on the reed.Could a
similar effect be achieved by removing a square from the reedplate (where the
reed is attached)? This would seem to eliminatethe need to press the reed down
(bending it slightly) and it wouldleave no angle at the edge of the reedplate.
Would this increasereed longevity and response sufficiently to make it worth the
work?(I do realize that this is NOT something that would be done at the
factory.)A second question: Rick gave a very thorough description of
theimprovement in aerodynamics by chamfering the reed. Has anyone(specifically
an engineer trained in aerodynamics as well as mechanics)done a study of the
optimal aerodynamic shape of a reed to facilitatereed activation and
oscillation? If so, have the results of that study been made public?I realize
that there are tradeoffs involved (some of which are the costsassociated with
creating a nonlinear surface shape in a productionenvironment). I'm just
curious...Thanks!Crazy Bob  
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