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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