[Harp-L] RE: Reed Measurements (Request For Information)

[Robert Coble <robertpcoble@xxxxxxxxxxx>]

Thank you, Rick, for the additional information and the reference document.
I'm intrigued by the idea of rolling out a reed vice punching it out. It seems
like it might produce a superior reed. Even if I had seen this old document,
I would not have known that "tombac" was the material used for chromatic reeds!

I've made up a diagram of the various reed dimensions (based on Seydel Blues Sessions).
I'm pretty sure that the side tolerance of the reed tongue (+/- 0.0125mm; 0.0005in) will
be the tricky part. Everything else about a reed seems to not be as critical for tolerance.

I haven't gotten together yet with my machinist friend to start working on a punch-and-die.
He's had some family crises to deal with, so it may take a while to get going with the design.

Regards,
Crazy Bob


Date: Mon, 23 May 2011 10:13:39 +0100
Subject: Re: Reed Measurements (Request For Information)
From: rickepping@xxxxxxxxx
To: robertpcoble@xxxxxxxxxxx
CC: harp-l@xxxxxxxxxx

Sorry, I don't have any more information on the process used to roll wire into reeds.  Many of the 19th Century harps' reeds had narrower rivet pads than do modern harps, and I don't know that it makes any significant difference to the harp's performance, so the diameter of wire you use would be determined more by the properties of the material, and the material will have to be something chosen from all the available, off-the-shelf metals you can find, be they sheet for punching or wire for rolling.  You should look more to the desired final thickness of the reed blank you roll, as the more you reduce the wire's thickness by rolling, the harder the material will become. 


Just for interest, an 1885 book I have by Ernest Spon entitled, Workshop Receipts contains recipes for various brass and other alloys.  The 1883 edition appears to be much the same and is available here as a pdf download:

http://www.wkfinetools.com/mLibrary/Spon/1883-WorkshopReceipts/1883-WorkshopReceipts.asp

The brass alloys are on page 10 of the book (page 14 of the pdf).  Page 11 has two recipes for tombac, an old name Hohner used for its chromatic reeds.
Best regards,Rick