Re: [Harp-L] Reed Material from Micro-Mark

["Vern Smith" <jevern@xxxxxxx>]

Most reeds are cut from stock about .012" thick.  This will 
be the thickness of the square bases and the slugs at the 
tip of the low pitched reeds.  You can buy shim stock from 
McMaster Carr if you wish to make reeds.

Unfortunately, reeds are not the same thickness from root to 
tip.  They have a non-linear taper called a thickness 
profile.  I doubt that you can make satisfactory reeds from 
.006" or .008" flat stock.  The low-pitched reeds can be 
.010" thick near the root.  The high-pitched reeds can be 
.002" thick near the tip.  None of them is the same 
thickness from root to tip.

To make satisfactory reeds, you must:

1. Know what the profile should be.  You can get an idea by 
using a micrometer  at several places along the length of a 
commercial reed. I made a little fixture that uses a dial 
indicator feeling the reed on a little track on which it can 
slide.

2. Cut the profile into the stock.  This is much more 
difficult and usually requires a special machine.

3. Understand that the design of a reed involves more than 
pitch,  You can make a reed of the correct pitch whose 
stiffness is too little or too great making it unresponsive 
to normal blowing/drawing pressure.  It can be the correct 
pitch and stiffness but have too much stress at one place,

The pitch of a reed is very sensitive to changes of 
thickness near the root where most of the bending tends to 
occur.  You can verify this by removing a tiny bit of 
material in this area and observing the amount the pitch 
decreases.  Using stock that is a couple of mils too thick 
or thin can really start you out in "left field." 
design-wise.

One purpose of the taper is to spread the stress more evenly 
along the length of the reed.  A flat reed will have a huge 
amount of stress near the rivet and fail there quickly. 
Most reed designs make the root a bit thicker/stronger to 
reduce the stress there.

Making reeds is an interesting challenge, there is much more 
to it than cutting a piece flat stock to the outline of a 
reed and installing it in your harp.

Good luck. Let us know how you fare.

Vern








----- Original Message ----- 
From: "Harvey Berman" <cscharp@xxxxxxxxxxxxx>
To: <harp-l@xxxxxxxxxx>
Sent: Tuesday, June 23, 2009 12:20 PM
Subject: [Harp-L] Reed Material from Micro-Mark


Micro-Mark lists .006" sheets of Phosphor Bronze, which 
comes in a pack of 3 5X7 sheets. The price is $11.55. With 
the exception of the weight and the pad, this is pretty 
close to what most reeds should be, so I ordered a pack to 
experiment with. When the pack came, it was actually .008", 
which is too thick.

I talked to Mico Mark, and they called the manufacturer, who 
told them that the .006" is not going to be available, so 
they shipped them .008 So, if anyone is considering ordering 
this product, Part number 83100, be advised that it is 
really .008".

I decided to cut out a reed, and I started sanding the 
thickness, and blowing the reed. When I got to almost .006, 
I got a pretty good sounding reed. It took a long time with 
my sanding wand, but it worked, and left me with a pad that 
is .008".

If anyone can recommend a quick method of cutting .008" 
Phosphor Bronze, and also for taking off .002" in thickness, 
without a huge investment in metalworking tools, I would 
appreciate it.

Harvey Berman
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