String wire gauges in Japanese pianos

[Keith Jones]

Thanks for this info. I've been told that one shouldn't replace wire on 
German pianos with American wire. (I mean replacing single broken strings, 
not complete re-stringing.) What do others think? Do we need to carry 
around two complete sets of wire sizes?

Keith Jones

At 05:00 AM 6/12/2003 -0700, you wrote:
>Robin,
>
>Any metric wired piano will have slightly different sized wire than an 
>American gauge wired piano.  There are some sizes which match very 
>closely, and others which do not.  Here is a comparison table:
>
>_____________________________________
>           American Wire            Metric  wire
>Gage         .001"     mm           .001"   mm
>
>    12   .029"  .737mm   .0285"  .725mm
>  12.5   .030"  .762     .0295   .750
>    13   .031"  .787     .0305   .775
>  13.5   .032"  .813     .0315   .800
>    14   .033"  .838     .0325   .825
>  14.5   .034"  .864     .0335   .850
>    15   .035"  .889     .0344   .875
>  15.5   .036"  .914     .0354   .900
>    16   .037"  .940     .0364   .925
>  16.5   .038"  .965     .0374   .950
>    17   .039"  .991     .0384   .975
>  17.5   .040"  1.016    .0394  1.000
>    18   .041"  1.041    .0404  1.025
>  18.5   .042"  1.063    .0413  1.050
>    19   .043"  1.092    .0423  1.075
>  19.5   .044"  1.118    .0433  1.100
>    20   .045"  1.143    .0443  1.125
>  20.5   .046"           .0453  1.150
>    21   .047"  1.194    .0463  1.175
>  21.5   .048"           .0472  1.200
>    22   .049" 1.245     .0482  1.225
>    23   .050" 1.295     .0512  1.300
>  23.5                           .0531  1.350
>    24   .053" 1.346     .0551  1.400
>  24.5                                   .0571  1.450
>    25   .055" 1.397     .0591  1.500
>    26                                   .0630  1.600
>
>As you can see, metric wire sizes step in .025mm increments while English 
>sizes step in .001" increments.  This causes the metric wires to be 
>slightly different, and usually smaller, than English sizes.  Once you 
>reach #16 they are very close to the same, then at #23 the metric wire 
>becomes larger than the English size.  This is the reason for being 
>careful what you replace the wire with.  Measuring the wire is good advice.
>
>Most Roslau wire sold in the US has been re-packaged to match the closest 
>English size.  If you buy it in Germany it will be the metric sizes as 
>listed above.  Same with Suzuki wire from Japan.
>
>Don't worry about wire sizes leading to string breakage - this is not the 
>case.  If you go smaller, the string tension for a given pitch goes down 
>proportionally along with the string strength.  This means that the 
>percentage of tensile strength will be almost exactly the same on a given 
>note if you replace the wire with a size larger or smaller than was 
>intended.  You can screw up the tuning and tone pretty well, but the 
>string will not be any more or less likely to break if the wire is wrong.
>
>There have been lots of threads on string breakage here, so you can check 
>the archives.  The bottom line is almost always heavy use combined with 
>worn hammers. Replace all the affected wire, shape the hammers and keep 
>them shaped, and the string breakage will be reduced to a minimum.
>
>Don Mannino RPT
>Kawai America