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I obtain my overwound bass clavichord strings from Tim Hamilton (in the
Boston area), and he seems knowledgeable about the sizes that will work for
a certain pitch level (i.e., 415 vs. 440).

Dr. Carol lei Breckenridge
Professor Emerita, Central College in Iowa

On Nov 20, 2017 12:35 PM, "Phillip Allen" <[log in to unmask]>
wrote:

> Hi All,
>
> I am “almost” finished buildinng my first clavichord, a Hubert 1784 (serial
> #8604) drawn by Loucks (1974) / revised Loucks (1977 & 1981) that I
> purchased from Friends of St Cecilia’s Hall in Edinburgh. From the
> temperament question I posted last week I have decided to tune it to 440
> equal temperament.
>
> I built a wooden string winding lathe to make the 22 over-wound strings and
> it seems to work quite well. The stringing schedule for these 22 over-wound
> strings is appended below. The 0.016” yellow-brass strings were purchased
> from The Instrument Workshop (http://www.fortepiano.com/) while the copper
> covering (110 Copper wire) from McMaster-Carr (www.mcmaster.com). Since
> there was no 0.015” Cu wire I substituted 0.016” Cu-wire.
>
> The general procedure was:
>
> 1. Hitch-pin loop on each end (main & sacrificial/temporary)
>
> 2. Mark with a sharpie pen area over tangent & bridge
>
> 3. Tension wire on Lathe, using PitchLab ~45hz F#1,
>
> 4. Loop Cu-wire through main hitch-pin loop, tag-end wind along helix for
> 1cm to anchor it.
>
> 5. Start the over-wound spiral using a piece of leather to hold the
> tension. In the middle the tension normally deflects the yellow-brass core
> wire 2-3cm from its center line. I hope that makes sense since I have no
> idea of lbs/kg of force that I am putting on the Cu-wire.
>
> 6. Cu-wire is wound as an open spiral over the entire length but wound
> closed over were the tangents and bridge are marked out with a sharpie pen.
>
> 7. Lathe tension was removed and the sacrificial/temporary loop cut off.
>
> The over-wound strings look real good just like pictures on the internet of
> store-bought strings! They even sound very nice.
>
> Of the 22 made I have broke more than 12 of them trying to tune them! They
> keep breaking right at the tuning peg. Typically they are breaking two full
> notes below (need F# and break when they get to E or F). So far I have
> managed to splice a piece of 0.018” yellow-brass to the broken end for two
> strings and get them tuned up. No such splicing luck for the others.
>
> I have just made another wire and tightly/close wound the Cu-wire all the
> way from the bridge past the tuning pin thinking the Cu was weakening the
> yellow-brass as it rests on the tuning peg. It also broke like the others.
>
> So what am I doing wrong?
>
> Should I switch to some sort of iron wire core?
>
> Is the Cu-wire the problem?
>
> Is the wire-core or over-wound tension while winding wrong?
>
> Thanks for any suggestions to resolve this problem. The winding lathe is
> hand-crank operated and my girlfriend is getting tired of turning this
> stupid crank!
>
> Phil
>
> String # Note #1 Speaking Length_1 Yellow_Brass_Core Cu_Wrap
> 1 C 1097 0.016 0.016
> 2 C 1097 0.016 0.016
> 3 C# 1082 0.016 0.016
> 4 C# 1082 0.016 0.016
> 5 D 1069 0.016 0.012
> 6 D 1069 0.016 0.012
> 7 Eb 1054 0.016 0.012
> 8 Eb 1054 0.016 0.012
> 9 E 1038 0.016 0.012
> 10 E 1038 0.016 0.012
> 11 F 1022 0.016 0.012
> 12 F 1022 0.016 0.012
> 13 F# 1007 0.016 0.012
> 14 F# 1007 0.016 0.012
> 15 G 986 0.016 0.012
> 16 G 986 0.016 0.012
> 17 G# 968 0.016 0.010
> 18 G# 968 0.016 0.010
> 19 A 948 0.016 0.010
> 20 A 948 0.016 0.010
> 21 Bb 923 0.016 0.010
> 22 Bb 923 0.016 0.010
>
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>

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Note:  opinions  expressed on HPSCHD-L are those of the  individual con-
tributors and not necessarily  those of the list owners  nor of the Uni-
versity of Iowa.  For a brief  summary of list  commands, send mail to
[log in to unmask]  saying  HELP .
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::